WO2020225780A1 - An electrical stimulation device with synchronized pulsed energy transfer - Google Patents

An electrical stimulation device with synchronized pulsed energy transfer Download PDF

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Publication number
WO2020225780A1
WO2020225780A1 PCT/IB2020/054362 IB2020054362W WO2020225780A1 WO 2020225780 A1 WO2020225780 A1 WO 2020225780A1 IB 2020054362 W IB2020054362 W IB 2020054362W WO 2020225780 A1 WO2020225780 A1 WO 2020225780A1
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WO
WIPO (PCT)
Prior art keywords
energy
stimulation
pulse
mode
data
Prior art date
Application number
PCT/IB2020/054362
Other languages
French (fr)
Inventor
Hubert Martens
Stephen Mark Gee
Original Assignee
Salvia Bioelectronics B.V.
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Application filed by Salvia Bioelectronics B.V. filed Critical Salvia Bioelectronics B.V.
Publication of WO2020225780A1 publication Critical patent/WO2020225780A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0526—Head electrodes
    • A61N1/0529—Electrodes for brain stimulation
    • A61N1/0531—Brain cortex electrodes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0526—Head electrodes
    • A61N1/0529—Electrodes for brain stimulation
    • A61N1/0534—Electrodes for deep brain stimulation
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/02—Details
    • A61N1/04—Electrodes
    • A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0551—Spinal or peripheral nerve electrodes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36007—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation of urogenital or gastrointestinal organs, e.g. for incontinence control
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/3605—Implantable neurostimulators for stimulating central or peripheral nerve system
    • A61N1/3606—Implantable neurostimulators for stimulating central or peripheral nerve system adapted for a particular treatment
    • A61N1/36071—Pain
    • A61N1/36075—Headache or migraine
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372—Arrangements in connection with the implantation of stimulators
    • A61N1/378—Electrical supply
    • A61N1/3787—Electrical supply from an external energy source

Definitions

  • the present disclosure relates to a method of controlling pulse energy of a device for providing electrical tissue stimulation. It also relates to such a stimulation device.
  • Electrical stimulation systems may be used to deliver electrical stimulation therapy to patients to treat a variety of symptoms or conditions such as headaches, lower back pain and incontinence.
  • the system may comprise one or more devices, and be at least partially implantable.
  • a stimulation device typically comprising a therapeutic lead (a lead comprises stimulating electrodes and interconnections), to provide electrical stimulation as effectively as possible.
  • US application US2015/297900 describes a device for providing an implantable lead with wireless energy, the device including; one or more non-inductive antennas substantially enclosed within the housing and configured to receive
  • connection pads are configured to couple with one or more electrodes in the implantable lead and form an electric connection over which the connection pads provide the extracted excitation waveforms from the electronic circuit to the electrodes in the implantable lead, the implantable lead being separate from the device.
  • US application US2009/105782 describes methods and implantable apparatus that do not require an onboard, implanted power supply. Power may be supplied from outside of the body by near-field inductive coupling with an external power supply provided in a support article (e.g., garment) worn by the patient. Power may also be supplied by providing an antenna for harvesting ambient RF energy and converting it into DC power. In addition, remote wireless programming of the parameters that specify the nature of current pulses provided is provided.
  • US application US2006/074450 describes implantable stimulation systems comprises two functional modules: i) a programmable pulse generator module, and ii) a stimulus-receiver module. The stimulus-receiver module is designed to provide stimulation/blocking pulses with an external stimulator. An external device acts as a programmer and as an external stimulator. The system uses implantable power source until stable external power is available. A power select circuitry switches between implanted power source and external power source, when its available.
  • US application US2015/099959 describes an electrode array (10) configured for implantation into a subject.
  • the electrode array (10) includes an organic substrate material (12) configured to be implanted into an in vivo environment and to optionally dissolve after implantation into the in vivo environment and be absorbed by the in vivo environment, and an electrode (14) mounted to the organic substrate material (12) and configured to acquire signals generated by the in vivo environment.
  • a conductive trace (16) is formed between the electrode (14) and the connection pad (2) which includes a conductive ink that is MRI-compatible.
  • a method of controlling pulse energy of a tissue stimulation device comprising: one or more energy receivers, configured and arranged to wirelessly receive a pulse train of energy from an associated stimulation energy transmitter when the associated stimulation energy transmitter is proximate; and one or more stimulation electrodes; a pulse energy controller, configured and arranged to receive electrical energy from the one or more energy receivers and to transfer electrical energy as one or more electrical stimulation pulses to the one or more stimulation electrodes; the method comprising: configuring and arranging the pulse energy controller to operate in a high- energy mode, wherein electrical energy is transferable; and in a lower-energy mode, wherein the transfer of electrical energy to one or more stimulation electrodes is restricted; configuring and arranging the stimulation device to detect when first predetermined conditions have been detected whereby the pulse energy controller is switched from the lower-energy mode to the high-energy mode substantially
  • the pulse energy controller is switched from the high-energy mode to the lower-energy mode between individual pulses of the pulse train of energy received.
  • the stimulation device can accurately determine when it should switch itself to the high- energy mode, allowing it to be ready for operation as quickly as possible.
  • the amount of wasted transmitted energy may be reduced - energy may be wasted if the electrical energy is being transmitted and the stimulation device is not ready.
  • the time that the stimulation device is in lower-energy mode may be longer - for example, the electrical interconnections and the stimulation electrodes are only connected when they are needed for actual stimulation, further reducing the risk of timing mismatches and/or unwanted energy storage.
  • Lower-energy mode consumes substantially less energy than the corresponding high-energy mode - so the controller may conserve energy, and only become active when needed.
  • the controllers may be configured and arranged to detect predetermined conditions that should be satisfied to switch between the high-energy mode and the lower- energy mode. These predetermined conditions may be pre-programmed (in other words, not transmitted immediately before use using a data receiver). Additionally or
  • one or more parameters may be (re)programmable after receiving one or more instructions.
  • the tissue stimulation device is configured and arranged to monitor electrical energy received from the associated stimulation energy transmitter; and to derive the first and/or second
  • predetermined conditions from the monitored electrical energy. This is an example of providing the moments in time to switch between modes as appropriate conditions, and configuring the pulse energy controller to evaluate these conditions.
  • the tissue stimulation device is configured and arranged to monitor electrical energy received at the one or more energy receivers.
  • a stimulation device which further comprises a data receiver, configured and arranged to wirelessly receive, from the one or more energy receivers, stimulation data, the method further comprising: configuring the tissue stimulation device to derive the first and/or second predetermined conditions from an instruction comprised in the stimulation data; and/or configuring the tissue stimulation device to predetermine one or more corresponding characteristics of one or more subsequent electrical stimulation pulses from the stimulation data.
  • a highly configurable device By allowing the device to receive one or more instructions (pre)determining the condition under which the energy mode of the pulse energy controller is switchable and/or one or more characteristics of the energy pulses, a highly configurable device is provided.
  • the pulse energy controller is configured and arranged to provide two or more electrical stimulation pulses after switching from the lower-energy mode to the high energy mode, and before any subsequent receipt of stimulation data.
  • the pulse energy controller By configuring the pulse energy controller to provide two or more electrical stimulation pulses as instructed, the data-rate may be kept even lower - repetition of pulses is relatively straightforward to implement in the logic control. In addition, there is still a high degree of customization possible as important parameters determining characteristics of the pulse may still be modified between pulse sequences.
  • the pulse energy controller may also operate more independently - this is particularly useful if data communication is interrupted, or even lost due to interference.
  • the pulse energy controller further comprises one or more electrode switches, configured and arranged to restrict the transfer of electrical energy to one or more stimulation electrodes when the pulse energy controller is operating in the lower-energy mode.
  • the stimulation data may comprise an instruction to connect and/or disconnect one or more stimulation electrodes, and the pulse energy controller is configured and arranged to connect and/or disconnect the energy pulse controller through one or more electrical connections to one or more stimulation electrodes as instructed.
  • connection By allowing selection (connection) of one or more electrodes, an even further degree of customization is provided as electrical stimulation may be provided to tissue proximate one or more selected stimulation electrodes.
  • the pulse generator By configuring and arranging the pulse generator to provide disconnection, unwanted energy storage in leads may also be reduced or even eliminated. The selection may be determined by the pulse energy controller. Additionally or alternatively, the stimulation data may comprise one or more instruction about the one or more electrodes to be selected.
  • the pulse energy controller further comprises a pulse timing clock, configured and arranged to influence a temporal characteristic of the one or more electrical stimulation pulses provided by the pulse energy controller.
  • a temporal characteristic may be a stimulation pulse start time, a pulse width and/or a stimulation pulse end time.
  • the clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced.
  • the pulse energy controller further comprises a mode timing clock, configured and arranged to switch from the high-energy mode to the lower-energy mode and/or from the lower-energy mode to the high-energy mode.
  • the mode clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced, and the length of time spent in lower-energy mode may be increased.
  • the energy transmitter further comprises an energy timing clock, configured and arranged to influence a temporal characteristic of the stimulation energy, the stimulation data comprising an instruction to synchronize one or more timing clocks, and configuring and arranging the pulse energy controller to synchronize the energy timing clock to the pulse timing clock and/or mode timing clock.
  • a temporal characteristic may be an energy start time, an energy pulse width and/or an energy end time.
  • the energy clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced.
  • a stimulation system comprising: a tissue stimulation device, and a stimulation energy transmitter, configured and arranged according to any of the embodiments described.
  • a high degree of interoperability and reliability is provided with a matched set of an energy transmitter and a tissue stimulation device.
  • FIG. 1A, IB & 1C depict an example of an implantable distal end of a stimulation device
  • FIG. 2A, 2B & 2C depict an example of a proximal end of a stimulation device
  • FIG. 3 schematically depicts a detailed example of a pulse energy controller
  • FIG. 4A, 4B and 4C depict three different data communication and energy transmission signal operating configurations;
  • FIG. 5 and FIG. 6 depict examples of nerves that may be stimulated to treat headaches;
  • FIG. 7 depicts examples of nerves that may be stimulated for other treatments.
  • FIG. 8 depicts examples of data communication and energy transmission signals in an operating configuration.
  • stimulation devices described herein may comprise a stimulation energy source and an implantable end - the implantable end comprises one or more stimulation electrodes.“Implantable end” means that at least this section of the stimulation system is configured and arranged to be implanted. Optionally, one or more of the remaining sections of the stimulation systems may also be configured and arranged to be implanted.
  • FIG. 1A, IB & 1C depict longitudinal cross-sections through a first embodiment 100 of an implantable distal end of a stimulation device comprising:
  • the substrate 300 disposed along a longitudinal axis 700, the substrate having a first 310 and second 320 surface disposed along substantially parallel transverse planes 700, 720.
  • the first surface 310 lies in a plane comprising the longitudinal axis 700 and a first transverse axis 720 - the first transverse axis 720 is substantially perpendicular to the longitudinal axis 700.
  • the plane of the first surface 310 is substantially perpendicular to the plane of the cross-section drawing (substantially perpendicular to the surface of the paper).
  • the substrate 300 has a thickness or extent along a second transverse axis 750 - this second transverse axis 750 is substantially perpendicular to both the longitudinal axis 700 and the first transverse axis 720 - it lies in the plane of the drawing (along the surface of the paper) as depicted.
  • the first surface 310 is depicted as an upper surface and the second surface 320 is depicted as a lower surface.
  • the axes are given nominal directions:
  • the longitudinal axis 700 extends from the proximal end (not depicted) on the left, to the distal end, depicted on the right of the page;
  • the second transverse axis 750 extends from bottom to top as depicted.
  • the elongated substrate 300 may comprise an elastomeric distal end composed of silicone rubber, or another biocompatible, durable polymer such as siloxane polymers, polydimethylsiloxanes, polyurethane, polyether urethane, polyetherurethane urea, polyesterurethane, polyamide, polycarbonate, polyester, polypropylene,
  • silicone rubber or another biocompatible, durable polymer such as siloxane polymers, polydimethylsiloxanes, polyurethane, polyether urethane, polyetherurethane urea, polyesterurethane, polyamide, polycarbonate, polyester, polypropylene,
  • polyethylene polystyrene, polyvinyl chloride, polytetrafluoroethylene, polysulfone, cellulose acetate, polymethylmethacrylate, polyethylene, and polyvinylacetate.
  • Suitable examples of polymers, including LCP Liquid Crystal Polymer), are described in “Polymers for Neural Implants”, Hassler, Boretius, Stieglitz, Journal of Polymer Science: Part B Polymer Physics, 2011, 49, 18-33 (DOI 10.1002/polb.22169), In particular, Table 1 is included here as reference, depicting the properties of Polyimide (UBE U-Vamish-S), Parylene C (PCS Parylene C), PDMS (NuSil MED- 1000), SU-8 (MicroChem SU-8 2000 & 3000 Series), and LCP (Vectra MT1300).
  • Flexible substrates 300 are also preferred as they follow the contours of the underlying anatomical features very closely. Very thin substrates 300 have the additional advantage that they have increased flexibility.
  • the flexible substrate 300 comprises an LCP, Parylene and/or a Polyimide.
  • LCP are chemically and biologically stable thermoplastic polymers which allow for hermetic sensor modules having a small size and low moisture penetration.
  • an LCP may be thermoformed allowing complex shapes to be provided. Very thin and very flat sections of an LCP may be provided. For fine tuning of shapes, a suitable laser may also be used for cutting.
  • LCP substrates 300 with thicknesses (extent along the second transverse axis 750) in the range 50 microns (um) to 720 microns (um) may be used, preferably 100 microns (um) to 300 microns (um). For example, values of 150 um (micron), lOOum, 50um, or 25um may be provided.
  • substrate widths (extent along the first transverse axis 720) of 2mm to 20 mm may be provided using LCP, for example.
  • implantable substrates 300 must be strong enough to be implanted, strong enough to be removed (explanted) and strong enough to follow any movement of the anatomical feature and/or structure against which it is implanted.
  • LCP belongs to the polymer materials with the lowest permeability for gases and water. LCP’s can be bonded to themselves, allowing multilayer constructions with a homogenous structure.
  • polyimides are thermoset polymers, which require adhesives for the construction of multilayer substrates.
  • Polyimides are thermoset polymer material with high temperature and flexural endurance.
  • An LCP may be used, for example, to provide a substrate having multilayers (not depicted) - in other words, several layers of 25 um (micron) thickness.
  • Electrical interconnect layers may also be provided by metallization using techniques from the PCB (Printed Circuit Board) industry, such as metallization with a bio-compatible metal such as gold, silver or platinum. Electro-plating may be used. These electrical interconnect layers may be used to provide electrical energy to any electrodes.
  • a low aspect ratio is used for the elongated substrate to reduce the chance of implantation problems - for example a ratio of height (thickness or extent along the second transverse axis 750) to width (extent along the first transverse axis 720) of less than 10, such as 0.3mm high and 10mm wide.
  • substrates (and leads) having other cross-sections such as square, trapezoidal may be used.
  • the cross-section shape and/or dimensions may also vary along the longitudinal axis 700.
  • a substrate may be used with a substantially circular (which includes a circle, a flattened circle, a stadium, an oval and an ellipse) transverse cross-section - this may also be described as tubular or cylindrical.
  • the distal end 100 of the device depicted in FIG. 1 further comprises:
  • the stimulation electrode 200 has a longitudinal extent along the longitudinal axis 700 and a transverse extent along a first transverse axis 720, the transverse axis 720 being substantially perpendicular to the longitudinal axis 700 and substantially parallel to the second surface 320.
  • “Comprised in the second surface” means that stimulation electrode 200 is relatively thin, and attached to the second surface 320.
  • the electrode 200 may also be embedded in the second surface 320.
  • one or more stimulation electrodes 200 may be provided.
  • the number, dimensions and/or spacings of the stimulating electrodes 200 provided in the distal end 100 may be selected and optimized depending on the treatment - for example, if more than one electrode 200 is provided, each electrode 200 may provide a separate stimulation effect, a similar stimulation effect or a selection may be made of one or two electrodes 200 proximate the tissues where the effect is to be created.
  • the electrodes 200 may comprise a conductive material such as gold, silver, platinum, iridium, and/or
  • FIG. IB depicts a stimulation electrode 200, elongated along the longitudinal axis 200.
  • a stimulation electrode 200 elongated along the longitudinal axis 200.
  • an oval cross-section is suggested in FIG. 1 A and IB, any shape may be used, such a square, rectangular, triangular, polygonal, circular, elliptical, oval, and round.
  • An elongated electrode (or strip electrode) may also be used.
  • the distal end 100 of the device of FIG 1 further comprises:
  • one or more return (or ground) electrode 400 configured to provide, in use, a corresponding electrical return for one or more stimulation electrodes 200.
  • the electrical return 400 closes the electrical circuit.
  • one or more return (ground) electrodes may be provided:
  • the return electrode may be referred to as an anode.
  • anode the return electrode may be referred to as an anode.
  • IPG International Pulse Generator
  • Stimulation electrodes may similarly be referred to as cathodes.
  • the one or more return electrodes 400 may comprise a conductive material such as gold, silver, platinum, iridium, and/or platinum/iridium alloys and/or oxides.
  • a distal end (or lead) 100 suitable for implant may comprise, for example, 12 stimulation electrodes over a length of 15cm.
  • a stimulation electrode may have dimensions in the order of 6 to 8 mm along the longitudinal axis 700 and 3 to 5 mm along the first transverse axis 720, so approximately 18 to 40 square mm (mm 2 ). If a strip of 4 mm wide (extent along the first transverse axis 720) is provided as a return electrode, then a length (extent along the longitudinal axis 700) 4.5 to 10 mm also provides a tissue contact-area of 18 to 40 square mm (mm 2 ).
  • the distal end 100 of the device of FIG 1 further comprises:
  • one or more electrical interconnections 250 may also be provided configured to provide the electrode 200 with electrical energy. They may be comprised in the first surface 310, the second surface 320, in the substrate between the surfaces 310, 320, and any combination thereof.
  • the substrate 300 may be a multilayer, comprising one or more electrical interconnection layers to provide the electrode 200 with electrical energy.
  • the electrical interconnections are connected to a source of electrical power (not depicted).
  • the thickness extent of the substrate 300 along the second transverse axis 750 or the perpendicular distance between the first surface 310 and the second surface 320
  • the thickness may be typically approximately 150 um (micron) in the sections with no electrodes 200 or interconnections, 250 um in the sections with an electrode 200, and 180 um in the sections with an electrical interconnection 250.
  • electrical interconnection layers of 25 um (micron) may be used, for example.
  • FIG. IB depicts a view of the second surface 320 of the implantable distal end 100 of the device depicted in FIG. 1 A.
  • the second surface 320 is depicted in the plane of the paper, lying along the longitudinal axis 700 (depicted from bottom to top) and in the first transverse axis 720 (depicted from left to right).
  • the second transverse axis 750 extends into the page. This is the view facing the animal or human tissue which is stimulated (in use).
  • the first surface 310 is not depicted in FIG. IB, but lies at a higher position along the second transverse axis 750 (into the page), and is also substantially parallel to the plane of the drawing.
  • the substrate 300 extends along the first transverse axis 720 (considered the width of the distal end 100 of the stimulation device) between two extents.
  • the distal end 100 of the device may be implanted by first creating a tunnel and/or using an implantation tool.
  • the one or more return electrode 400 is depicted in FIG. 1 A and 1C, but not in FIG IB.
  • a source of energy may be configured and arranged to provide, in use, electrical energy to the stimulation electrode 200 with respect to the electrical return applied to the one or more return electrode 400.
  • This source of electrical energy may be, for example, disposed at a proximal end of the stimulation device:
  • an energy source such as a pulse generator (not depicted, see below), directly connected to the one or more interconnections 250;
  • one or more energy receivers such as one or more conductors, directly connected to the one or more interconnections 250.
  • the one or more conductors such as coils with one or more windings, being configured to wirelessly receive energy from an energy source, such as a wireless pulse generator (not depicted, see below).
  • a coil with one or more windings may also be described as an inductive antenna.
  • FIG. 2A, 2B & 2C depict longitudinal cross-sections through a first embodiment 150 of a proximal end of a stimulation device 100, 150.
  • the proximal end 150 comprises the same features as depicted in FIG. 1: - the elongated substrate 300, disposed along the longitudinal axis 700, with the first 310 and second 320 surfaces;
  • the first transverse axis 720 extends into the page as depicted, and the second transverse axis 750 extends from bottom to top as depicted;
  • the longitudinal axis 700 extends from the proximal end 150 on the left, to the distal end 100, towards the right of the page.
  • the dimensions of the substrate 300 (extent along the first transverse axis 720 or width, extent along the second transverse axis 750 or thickness) at the distal 100 and proximal end 150 are depicted as approximately the same. This is convenient if the device 100, 150 comprises the same substrate 300, allowing it to be made from a single piece of material - this is advantageous if the distal end 100 of the device is substantially completely implanted as this may reduce the risk of fluid ingress into the device.
  • the proximal end 150 of the device further comprises:
  • the one or more energy receivers 500 are comprised in the first surface 310.
  • the one or more energy receiver 500 may be comprised in the second surface 320 and/or between the first 310 and second surface 320. It may be advantageous to embed the one or more energy receivers 500 into the substrate 300 to resist the ingress of fluids and/or a coating may be applied on top of the one or more energy receivers 500.
  • a pulse energy controller 550 configured and arranged to receive electrical energy from the one or more energy receivers 500. It is further configured and arranged to provide stimulation energy through the one or more electrodes 200 as one or more electrical pulses. This changes the electrical potential and/or current applied to the one or more electrodes 200.
  • the pulse energy controller 550 may be connected to the one or more electrodes 200 through one or more interconnections 250. It may be further connected the one or more energy receivers 500 through one or more further
  • the pulse energy controller 550 is comprised between the first 310 and second surface 320. It may be advantageous to embed the pulse energy controller 550 into the substrate 300 to resist the ingress of fluids and/or a coating may be applied on top of one or more components of the pulse energy controller 550. This may also provide an additional protection layer for tissue from any electrical potentials present in the pulse energy controller 550. Alternatively, the pulse energy controller 550 may be comprised in the second surface 320 or the first surface 310.
  • one or more return (or ground) electrode 450 configured and arranged to provide, in use, a corresponding electrical return for one or more stimulation electrodes 200 which receive stimulation energy from the pulse energy controller 550.
  • the electrical return 450 closes the electrical circuit.
  • Any suitable configuration and arrangement may be provided - for example, as depicted, comprised in the second surface 320, proximate the pulse energy controller 550.
  • one or more return (ground) electrodes 450 may be comprised in the first surface 310.
  • a combination of one or more return electrodes 450 proximate the pulse energy controller 550 and one or more return electrodes 400 proximate the stimulation electrodes 200 may also be provided.
  • one or more stimulation electrodes 200 may be configured to be selectable by connecting or disconnecting the electrode 200 and/or a suitable interconnection 250.
  • one or more return electrodes 400, 450 may similarly be configured to be selectable by connecting or disconnecting the return electrode 400, 450 and/or a suitable interconnection 250.
  • an electrode 200, 400, 450 may be configurable (selectable) as a stimulation or return electrode - electrically, there is no substantial difference between a stimulation electrode 200 and a return electrode 400, 450.
  • a blocking capacitor in an electrical connection to a return electrode 400, 450 - this may also be configured to be selectable.
  • An associated stimulation energy transmitter 620 is configured and arranged to wirelessly transmit stimulation energy. Any suitable energy transmitter may be used, such as:
  • one or more lasers, LED’s or laser diodes configured and arranged to convert the energy pulses to light pulses for transmission;
  • electromagnetic transducers configured and arranged to convert the energy pulses to electromagnetic radiation pulses for transmission, such as RF (radio-frequency) or microwaves;
  • acoustic transducers configured and arranged to convert the energy pulses to acoustic pulses for transmission, such as ultrasound;
  • one or more electrical capacitive conductors configured and arranged to convert the energy pulses to electrical field pulses for transmission.
  • the transmitter components may be miniaturized using modem manufacturing technology. These technologies comprise at least one conductor.
  • an associated stimulation data transmitter 630 may also be provided, configured and arranged to instruct the tissue stimulation device 100, 150 how, where and when it should stimulate tissue by transmitting (providing) one or more parameters and/or one or more instructions as stimulation data 630.
  • Any suitable energy transmitter types (as indicated above for the stimulation energy transmitter 620 may be used. When used for data, security and safety issues may limit the choice, or require additional measures.
  • electromagnetic signals such as RF (radio -frequency) or
  • microwaves there are also no major bandwidth and/or data rate issues.
  • the available frequency bands e.g. the ISM bands
  • - acoustic and capacitive types may be limited in some configurations due to technical difficulties in achieving a relatively bandwidth and/or data rate.
  • the transmitters 620, 630 may be combined in the same device, sharing one or more components. Energy and data may be transmitted via the same channel, or separate channels may be provided. If using the same channel, the data may be transmitted substantially simultaneously as any energy, or substantially not
  • the stimulation transmitters 620, 630 may also comprise one or more components providing some degree of logic control and/or processing such that the tissue stimulation device 100, 150, and in particular the pulse energy controller 550, may be instructed in a more extensive way.
  • Any suitable energy receiver 500 may be used, including the types indicated as examples of energy transmitters 620.
  • the same or a similar type is used to provide a high degree of efficiency in the transmission of the stimulation energy 620.
  • photo-diodes may be used to convert incoming photons to electrical energy
  • coils may be used to convert magnetic energy to electrical energy
  • piezo-sensitive element may be used to convert acoustic energy to electrical energy.
  • These technologies comprise one or more conductors.
  • the pulse energy controller 550 receives at least a portion of wirelessly -transmitted stimulation energy 620.
  • the pulse energy controller 550 then transfers at least a portion of the received electrical energy to one or more stimulation electrodes 200 as one or more electrical stimulation pulses.
  • the pulse energy controller 550 is further configured and arranged to operate in:
  • the stimulation device 100, 150 is configured and arranged to switch the pulse energy controller 550 under predetermined conditions from the lower-energy mode 550 to the high-energy mode 550 and/or to switch from the high-energy mode 550 to the lower- energy mode 550.
  • the pulse energy controller 550 is further configured and arranged:
  • the pulse energy controller may conserve energy and only become active when needed.
  • the need for data transfer during operation is reduced, allowing a lower data rate to be utilized. This may reduce the complexity of the pulse energy controller.
  • the device 100, 150 may be configured and arranged before use to determine the conditions (predetermined conditions) under which the pulse energy controller 550 switches from the lower-energy mode 550 to the high-energy mode 550. This may be, for example, a certain period of time after energy signals with particular characteristics were detected. For example, detecting a level of energy within a particular time.
  • the data receiver 553 may be further configured and arranged to wirelessly receive, from the one or more energy receivers 500, stimulation data 630 comprising an instruction predetermining conditions for the pulse energy controller 550 to switch from the lower-energy mode 550 to the high-energy mode 550 and/or to switch from the high-energy mode 550 to the lower-energy mode 550.
  • the pulse energy controller 550 may, for example, comprise a suitably configured and programmed processor, controlling one or more parameters of the stimulation energy pulses, such as an intensity, a duration, a waveform shape, a frequency, and a repetition rate using one or more software or firmware methods. Additionally or alternatively, a hardware-based solution may be used, such as a state-machine implemented in an ASIC (Application-Specific Integrated Circuit).
  • ASIC Application-Specific Integrated Circuit
  • It may operate in a stand-alone mode, or it may be in regular communication with an external controller, or some combination thereof.
  • FIG. 3 schematically depicts a detailed example of a suitable pulse energy controller 550. It comprises the following non-limiting examples of four main functional units
  • the one or more energy receivers 500 may disposed at a convenient position to receive electrical energy from the stimulation energy transmitter 620.
  • One or more electrical interconnections 250 may be provided between the one or more energy receivers 500 and the interface.
  • One or more tuning components 500a such as inductors and/or capacitors, may be provided to increase the efficiency of the stimulation energy transfer between the one or more energy transmitters 620 and the one or more energy receivers 500 and/or to increase the efficiency of stimulation energy transfer between the one or more energy receivers 500 and the
  • one or more energy receivers 500 may be comprised within the pulse energy controller 550.
  • a power supply 551 configured and arranged to provide voltages and/or currents to power electronic and electrical components comprised in one or more of the functional units of the pulse energy controller 550. It is further configured and arranged to provide stimulation energy, suitable for tissue stimulation, to the one or more electrodes 200
  • the circuit may comprise a rectifier 551a to receive electrical energy from the one or more energy receivers 500 and to provide high voltage to a high voltage output 552.
  • one or more high voltage buffers 551b may also be connected to this high voltage.
  • a high voltage monitor 551c may be connected to the high voltage.
  • High voltage means a voltage range typically used for stimulation voltages. In the context of this disclosure, it is high compared to the voltage used for logic circuits.
  • a low voltage regulator 55 Id such as a Low-Dropout Regulator (LDO), may be used to provide a regulated low voltage to the Logic Control 553.
  • one or more low voltage buffers 55 le may also be connected to this low voltage.
  • a high voltage output 552 configured and arranged to transfer stimulation energy from the power supply 551 to the one or more electrodes 200, preferably as pulses. This may also be described as generating one or more stimulation pulses.
  • it may comprise a current source 552a, connected to the high voltage.
  • a current monitor 552b may be connected to measure the output of the current source 552a and/or one or more current monitors 552b may be connected to measure the current to one or more electrodes 200.
  • One or more electrode switches 552c having a connect and/or disconnect function, may be provided to allow the one or more electrodes 200 to receive energy individually or in combination with one or more of the other electrodes 200, 400, 450.
  • the one or more electrode switches 552c may be used to disconnect one or more electrodes 200 and/or one or more interconnections 250 to the electrodes 200 when the pulse energy controller 550 is switched to lower-energy mode 550.
  • the energy may be provided to pairs of electrodes 200 as differential potentials and/or currents. Additionally or alternatively, one or more of the electrodes 200 may be configured as a return (or ground) electrode. Additionally or alternatively, one or more return electrodes 400, 450 may be used as described above. Optionally, one or more capacitors 400b may be used to block any degree of unwanted DC component in the return connections. Optionally, one or more interconnections 250 may be provided between the high voltage output 552 and the one or more electrodes 200 and/or the one or more return electrodes 400, 450.
  • a logic control 553, configured and arranged to control the transfer of the stimulation energy from the one or more energy receivers 500 to the one or more electrodes 200, 400, 450.
  • it may comprise one or more controllers 553d, connected to the one or more electrode switches 552c, one or more clock generators 553c, a modulator 553a and a demodulator 553b.
  • the one or more controllers 553d are configured and arranged to provide one or more of the following functions:
  • the one or more clock generators 553c are configured and arrange to receive one or more parameters and/or instructions from the stimulation data 630.
  • they may be in direct or indirect connection with the interface and/or with the
  • predetermined conditions that should be satisfied to switch between the high-energy mode 550 and the lower-energy mode 550.
  • These conditions may be pre programmed (in other words, not transmitted immediately before use using a data receiver).
  • one or more parameters may be (re)programmable after receiving one or more instructions;
  • the stimulation data 630 may be in direct or indirect connection with the interface and/or with the demodulator 553b.
  • These parameters and/or instructions may be predefined.
  • one or more parameters and/or instructions may be (re)programmable after receiving one or more parameters and/or instructions;
  • one or more electrode 200 is electrically connected to the pulse energy controller 550.
  • they may be in direct or indirect connection with the one or more electrode switches 552c;
  • Electrodes 200, 400, 450 to control whether one or more electrode 200, 400, 450 are operated as a stimulation electrode 200 and/or a return electrode 400, 450;
  • pulse energy controller 550 to monitor one or more parameters relating to the operation of the pulse energy controller 550, such as one or more currents, voltages, energies, powers;
  • - to transmit data such as monitored data.
  • data such as monitored data.
  • they may be in direct or indirect connection with the interface and/or the modulator 553a;
  • data such as monitored data.
  • they may be in direct or indirect connection with a digital memory storage.
  • the pulse energy controller 550 may further comprise one or more measurement components, such as the high voltage monitor 551c and the stimulation current monitor 552b. These are configured and arranged to detect and/or monitor one or more parameters relating to the operation of the pulse energy controller 550. These may be provided to the controller 553d and/or modulator 553a so that the data may be stored and/or transmitted.
  • one or more measurement components such as the high voltage monitor 551c and the stimulation current monitor 552b. These are configured and arranged to detect and/or monitor one or more parameters relating to the operation of the pulse energy controller 550. These may be provided to the controller 553d and/or modulator 553a so that the data may be stored and/or transmitted.
  • the one or more parameters being monitored may provide an indication of the stimulation energy received in the pulse energy controller 550, either at a particular moment and/or over a period of time.
  • the data from such monitoring may be stored in suitable memory comprised in the pulse energy controller 550, and/or transmitted to an external storage.
  • the data transmitter 630 may optionally also be configured as a receiver for such monitoring data and the receiver 500 may also be configured as a transmitter for this monitoring data. Additionally or alternatively, the pule energy controller 550 may comprise a separate monitoring transmitter.
  • the pulse energy controller 550 is configured and arranged to provide the required stimulation energy pulses at the electrodes 200, 400, 450 in co-operation with the stimulation energy transmitter 620.
  • a dedicated kit may be provided of a cooperating stimulation energy transmitter 620 and a pulse energy controller 550.
  • a cooperating stimulation energy transmitter 620 may be also configured and arranged to provide instructions to a tissue stimulation device 100, 150 as stimulation data 630.
  • a cooperating stimulation energy transmitter 620 may comprise a cooperating stimulation data transmitter 630.
  • a dedicated kit may be provided of a cooperating stimulation transmitter 620, a cooperating stimulation data transmitter 630 and a pulse energy controller 550.
  • a pulse energy controller 550 may be configured to co-operate with a plurality of different stimulation energy transmitters 620. Additionally or alternatively, a stimulation energy transmitter 620 may be configured to co-operate with a plurality of different pulse energy controllers 550. Co-operation may be arranged by standardization and/or customization of one or more components.
  • the pulse energy controller 550 may be further configured and arranged to receive parameters and/or instructions from a user interface.
  • a pulse energy controller 550 may be configured to co-operate with a plurality of different stimulation data transmitters 630. Additionally or alternatively, a stimulation data transmitter 630 may be configured to co-operate with a plurality of different pulse energy controllers 550. Co-operation may be arranged by standardization and/or customization of one or more components. Allowing more than one co-operating stimulation transmitter 620, 630 may allow a healthcare professional to operate a pulse energy controller 550 in extensive, therapeutic and/or experimental ways, and the human or animal may have their own stimulation transmitter 620, 630 with more limited (everyday) functions.
  • a stimulation data transmitter 620 may be comprised in a mobile device, such as a mobile telephone. Additionally or alternatively, a monitoring data receiver may be comprised in sch a mobile device.
  • the pulse energy controller 550 is configured and arranged to receive stimulation data 630 comprising one or more parameters which predetermine one or more
  • a serial number of a transmitter may be provided - although the logic may be configured and arranged to only accept instructions from certain serial numbers (whitelist), in other configurations the serial number may be stored in an operation log; and
  • - a direct instruction, relating to a characteristic of the operation of the pulse energy controller 550 and/or the one or more stimulation pulses.
  • Such parameters and/or instructions which may be received in the stimulation data 630 may include:
  • a switch from higher-energy mode 550 to low-energy mode 550 a switch from low energy mode 550 to higher-energy mode 550: for example, the conditions to be met for a switch, a time indication of when a switch is to take please, a period of time that the pulse energy controller 550 is to be kept in that mode 550;
  • the parameters may represent absolute values, such as pulses of 200 millisecond, or relative (delta) values, for example +50%, +100 millisecond etc.
  • therapy (treatment) pulses for stimulation provided to the electrodes 200 may be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz.
  • suitable pulse parameters may be: 0 - 10 Volt, in particular 0.5 - 4.0 Volt, amplitude, 0 - 10 mA, 90 - 200 microseconds pulse width and 50 - 400 Hz repetition rate.
  • pulses received at the one or more energy receivers 500 may also be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz.
  • pulses transmitted by the stimulation energy transmitter 620 may also be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz
  • FIG. 8 depicts examples of data communication and energy transmission signals. These are provided as non-limiting examples to illustrate the operation of the stimulation device 100, 150 in a first configuration - configuration 1).
  • a series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation data 630, stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to the second electrode 200 # 2, and data (feedback) 570 transmitted using, for example, a modulator 553a. Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right. During a particular period of time, the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2. This is indicated as pulse [b].
  • the logic control listens for stimulation data 630 being transmitted.
  • the first pulse to occur is a pulse [a] of transmitted stimulation data 630 comprising one or more parameters and/or instructions.
  • a pulse [a] of transmitted stimulation data 630 comprising one or more parameters and/or instructions.
  • the timing of the electrical energy pulses received at the one or more receivers 500 determines to a substantially high degree the timing of the stimulation pulses provided to the selected electrode number 200 #2
  • the pulse energy controller 550 comprises a timer or clock, such as a clock generator 553c configured to act as mode timing clock.
  • the instruction may indicate, for example, absolute times to switch mode (tl and t2), and/or relative times (for example from the transmission of the data 630).
  • the pulse energy controller 550 After receiving the instructions and/or parameters 630, the pulse energy controller 550 configures itself appropriately:
  • One or more of these configurations may be performed immediately. Alternatively or additionally, one or more of these configurations may be scheduled to be performed immediately upon the switching of the mode 550 to high-power mode 550.
  • the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [b], and waits for the electrical energy to arrive.
  • Each pulse at the one or more receivers 500 comprises at least a portion of the electrical energy transmitted 620.
  • each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500.
  • the monitored data is transmitted 570 as pulse [1]
  • the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [b].
  • the pulse energy controller 550 is configured and arranged to switch from the lower-energy mode 550 to the high-energy mode 550 immediately before the receipt of electrical energy at the one or more energy receivers 500.
  • the stimulation device 100, 150 in general, and the pulse energy controller 550 in particular may accurately determine when it should switch itself to the high-energy mode 550, allowing it to be ready for operation as quickly as possible. This is possible because of the high degree of independent control.
  • the pulse energy controller 550 may even switch from the lower-energy mode 550 to the high-energy mode 550 substantially simultaneously with the receipt of electrical energy at the one or more energy receivers 500.
  • the amount of wasted transmitted energy may be reduced - energy may be wasted, for example, if the electrical energy is being transmitted 620 and the stimulation device 100, 150 is not ready. Also the time that the stimulation device 100, 150 is in lower-energy mode 550 may be longer - for example, the electrical interconnections 250 and the stimulation electrodes 200 are only connected when they are needed for actual stimulation, further reducing the risk of timing mismatches and/or unwanted energy storage.
  • the operation and signals depicted in FIG. 8 may be modified, depending on the configuration of the pulse energy controller 550. For example, if a lower degree of customization is required (standard operating configurations), the pulse energy controller 550 may be configured to operate in substantially the same way for an extended period of time.
  • modifying of one or more characteristics of the stimulation pulses provided to the one or more electrodes 200 may only be required once per hour or a few times per day, allowing the configuration to remain the same for a relatively large number of pulses.
  • the only instruction and/or parameter required in the stimulation data 630 is the time to switch to high-energy mode tl . Either the time tl is required, or conditions that the pulse energy controller 550 may evaluate to determine tl (the switch to high-energy mode 550) are required.
  • the data rate and communication overhead are relatively low, and the power efficiency is relatively high.
  • the accurate timing of the high-energy mode 550 means that the length of time in the lower-energy mode 550 may be optimized.
  • the pulse energy controller can be switched into high-energy mode 550 at an exact time, reducing the risk that the one or more stimulation pulses 620 is wholly or partially missed.
  • feedback data 570 may be sent at a convenient point during the operation
  • high-energy mode 550 is an operating mode 550 in which at least a portion of the electrical energy is transferrable from the one or more energy receivers 500 to one or more stimulation electrodes 200 as one or more electrical stimulation pulses. This may be considered to be the normal operating mode 550.
  • lower-energy mode 550 is a hibernating mode 550 when compared to the normal operating mode 550, wherein the transfer of electrical energy to one or more stimulation electrodes 200 is restricted.
  • high-energy mode 550 the transfer of electrical energy to these one or more electrodes 200 is not restricted, or at least substantially less restricted.
  • Lower-energy mode 550 consumes substantially less energy than the corresponding high-energy mode 550 - so the controller 550 may conserve energy, and only become active when needed.
  • one or more of the following measures may be taken to reduce energy consumption:
  • the one or more electrodes 200 and interconnections 250 which are scheduled to be connected in high-energy mode 550 may be disconnected using the corresponding electrode switch 552c;
  • - logic may be switched to a low energy mode 550, such as a lower low voltage and/or lower operating clock frequency;
  • the skilled person will also realize that a plurality of high-energy modes and/or a plurality of lower-energy modes may be predetermined and made selectable using appropriate instructions.
  • the stimulation device 100, 150 may be further configured to similarly switch between a high-energy and lower-energy modes substantially
  • the moments in time to switch between modes may be provided as appropriate conditions that the pulse energy controller 550 is configured to evaluate.
  • tl may be determined as the moment in time that a stimulation energy pulse 620 is detected that is longer than a predetermined time, such as 500 milliseconds. Additionally or alternatively, tl may be determined as the moment in time that the pulse received at the one or more receivers 500 exceeds a threshold voltage, such as 12 volts.
  • t2 may be determined as the moment in time that no stimulation energy pulse 620 has been detected for a predetermined time, such as 2 seconds. Additionally or alternatively, t2 may be determined as the moment in time that the pulse received at the one or more receivers 500 drops below a threshold voltage, such as 2 volts. Additionally or alternatively, t2 may be determined as immediately after detection of three subsequent pulses at the one or more receivers 500. Additionally or alternatively, t2 may be determined as a fixed time after tl, such as 5 seconds.
  • the pulse energy controller 550 may be configured to switch between the high-energy and lower energy modes directly using instructions and/or parameters transmitted with the stimulation data 630, and/or using instructions and/or parameters derived from (indirectly and/or using them to define conditions) instructions and/or parameters transmitted with the stimulation data 630. All these cases are considered to be included when the pulse energy controller 550 switches between modes “as instructed”.
  • stimulation energy transmitter 620 By suitable configuration of the stimulation energy transmitter 620, stimulation data transmitter and/or pulse energy controller 550, many more modes of operation may be provided.
  • the configuration depicted in FIG. 8 is referred to here as configuration 1) to allow easier comparison.
  • Three further non-limiting operating configurations are described below:
  • the power supply 551 comprises a power source, such as a storage capacitor.
  • the capacitor is sufficient to store charge for the entire stimulation period. The lower the stimulation frequency, the larger the size of the capacitor. The data communication and energy transmission signals are depicted
  • FIG. 4 A A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
  • pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2. This is indicated as pulse [e].
  • the logic control listens for stimulation data 630 being transmitted.
  • stimulation energy 620 is transmitted continuously over the whole time period depicted to charge the storage capacitor and to keep it charged.
  • the pulse [a] is the first pulse to occur, and it starts on the left-hand side.
  • the amplitude [a] of the stimulation energy may be substantially lower compared to a pulsed situation.
  • Stimulation energy is received continuously at the one or more receivers 500 over the same time period as for the stimulation energy 620.
  • the pulse [b] starts on the left- hand side at the same moment. At least a portion of the electrical energy received is used to charge the storage capacitor comprised in the power supply 551.
  • the next pulse to occur is a pulse [c] of transmitted stimulation data 630 comprising one or more parameters and/or instructions.
  • a pulse [c] of transmitted stimulation data 630 comprising one or more parameters and/or instructions.
  • the energy pulse controller 550 may calculate the moment in time t2;
  • one or more parameters indicating an amplitude, a pulse width, an interval (or duty cycle) and a number of stimulation pulses to be provided In this example, three equal pulses are to be provided to the electrode 200 #2.
  • the pulse energy controller 550 After receiving the instructions and/or parameters 630, the pulse energy controller 550 configures itself appropriately:
  • One or more of these configurations may be performed immediately. Alternatively or additionally, one or more of these configurations may be scheduled to be performed immediately upon the switching of the mode 550 to high-power mode 550.
  • the next pulse depicted [d] is a transmittal on the stimulation data 630 channel indicating that stimulation should start (start signal [d]).
  • the start signal [d] may be, for example, a pulse sent through the stimulation data 630 channel with a particular duration and/or amplitude. Or the next pulse sent through the stimulation data 630 channel within a particular time period.
  • the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [e].
  • the logic control 553 controls the high voltage output 552 to generate three energy pulses with the predetermined amplitude, pulse width, and interval, and to transfer them as three stimulation pulses [f], [g], [h] to the electrode 200 #2.
  • the monitored data is transmitted 570 as pulse [i], providing feedback data on the number of stimulation pulses provided to the electrode 200#2.
  • This data 570 [i] may be received by the stimulation energy transmitter 620, and used to modify or maintain one or more of the transmitter parameters during the reconfiguration.
  • the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [e].
  • the data rate and communication overhead are relatively low, and the power efficiency is relatively high.
  • the accurate timing of the high-energy mode 550 means that the length of time in the lower-energy mode 550 may be optimized.
  • feedback data 570 may be sent at a convenient point during the operation
  • the data-rate may be kept relatively low without requiring a highly complex pulse energy controller - repetition of pulses (generating two or more pulses after switching from the lower-energy mode 550 to the high energy mode 550, and before any subsequent receipt of stimulation data (630)) is relatively straightforward to implement in the logic control 531.
  • Complex means anything found in a device which affects factors such as cost, lifetime, reliability and/or size - for example, the type and number of electrical components and integrated circuits, the type and number of antennas, the amount of programmable logic, the amount of memory storage, the presence of high-power components, etc.
  • the level of complexity is affected, in general, by the functionality which is designed into the device - for example, the type and variation in the waveforms of the stimulation pulses to be provided, the degree of customization available, the number of different types of data/energy transmitters supported, etc.
  • the pulse energy controller 550 may operate more independently. This is particularly useful if data communication is interrupted, or even lost due to interference.
  • disadvantages of configuration 2) include the pulse energy controller 550 requiring a relatively high degree of energy storage. For example, a buffer capacitor of up to 2 microFarad (uF) may be required. This increases the complexity and cost of the energy controller. In addition, large capacitors may not be possible in IC package sizes, increasing the volume of the pulse energy controller 550.
  • the logic control 553 needs to be moderately complex to respond to different control parameters. It may also reduce the reliability and operating lifetime, and may provide a risk to the patient.
  • the energy pulse generator 550 may, for example, comprise one or more electrode switches, comprised in the high voltage unit 552 under control of the logic control 553.
  • Configuration 3 Pulsed energy transfer: similar to configuration 2), except that for this configuration, either no power source, or a greatly reduced power source, is required within the power supply 551.
  • FIG. 4B A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
  • feedback transmitted using, for example, a modulator 553a.
  • Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right.
  • the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2, and repeated twice. This is indicated as three pulses [c].
  • the logic control listens for stimulation data 630 being transmitted.
  • the first pulse to occur is pulse [a], starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions for the subsequent pulse.
  • pulse [a] starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions for the subsequent pulse.
  • stimulation data 630 comprising one or more parameters and/or instructions for the subsequent pulse.
  • the pulse energy controller 550 may calculate the moment in time t2 for the next pulse;
  • the interval between the pulses is to be determined by the appropriate start signal, pulse [a] on the stimulation data channel 630 and by the timing of the electrical energy received at the one or more receivers 500.
  • the stimulation pulse is only provided to the electrode 200 #2 if the pulse energy controller 550 is in high-energy mode 550 (triggered by the start pulse [a]) when the energy pulse is received 500.
  • the pulse energy controller 550 After receiving the instructions and/or parameters 630, the pulse energy controller 550 switches the mode 550 to high-power and substantially simultaneously configures itself appropriately:
  • the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [b]
  • a pulse [c] of stimulation energy 620 is transmitted.
  • a corresponding pulse [d] is received at the one or more receivers 500. It comprises at least a portion of the electrical energy transmitted 620.
  • each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500
  • the monitored data on the pulse width of that pulse 200 #2 is transmitted 570 as pulse [f
  • the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [b].
  • the pulse energy controller 550 After detection of a second stimulation data transmission 630, interpreted as start signal [a], the pulse energy controller 550 switches from lower-energy mode 550 to high- energy mode 550, as indicated by the second transition from 0 to 1 of waveform [b], the pulse energy controller configures itself according to the instructions and/or parameters in the second stimulation data 630 transmission, and the cycle of pulses [c], [d], [e], [f] is repeated.
  • the instructions and/or parameters may be changed per pulse, allowing a very high degree of customization.
  • the pulse energy controller 550 again switches from high- energy mode 550 to lower-energy mode 550, as indicated by the second transition from 1 to 0 of waveform [b].
  • the pulse energy controller 550 switches from lower-energy mode 550 to high- energy mode 550, as indicated by the third transition from 0 to 1 of waveform [b]
  • the pulse energy controller configures itself according to the instructions and/or parameters in the third stimulation data 630 transmission, and the cycle of pulses [c], [d], [e], [f] is repeated.
  • the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the third transition from 1 to 0 of waveform [b].
  • the instructions and/or parameters comprised in the stimulation data 630 may be further reduced, allowing a relatively simple logic control 553.
  • Configuration 3) may also be modified such that the amplitude and pulse width of the stimulation pulses provided to the electrode 200 #2 are determined by the energy received, and the pulse duration, at the one or more receivers 500 and the pulse.
  • simplification of the energy controller 550 may increase the reliability and operating lifetime.
  • disadvantages may include a relatively low power efficiency and relatively high data rates and communication overheads.
  • Additional problems may occur due to timing mismatches with configuration 3) - for example, if the stimulation energy 620 [d] is transmitted too early (before the pulse energy controller 550 has switched to high-energy mode 550 [c] and prepared itself to generate and provide the stimulation pulse [f ), then excess energy may need to be dissipated within the pulse energy controller 550.
  • any charge being retained to power the logic in the lower-energy mode 550 may become exhausted prematurely due to the additional load.
  • Configuration 4 Synchronized pulsed energy transfer: similar to configuration 3), except that for this configuration, parameters about the stimulation pattern are provided first, and not with each pulse. As with configuration 3), less charge needs to be stored between providing the stimulation pulses to the electrodes 200.
  • FIG. 4C A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
  • feedback transmitted using, for example, a modulator 553a.
  • Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right.
  • the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2, and repeated twice. This is indicated as three pulses [c].
  • the logic control listens for stimulation data 630 being transmitted.
  • the first pulse to occur is pulse [a], starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions.
  • pulse [a] starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions.
  • stimulation data 630 comprising one or more parameters and/or instructions.
  • the pulse energy controller 550 may calculate the moment in time t2, and this is repeated for each pulse;
  • the interval between the pulses is to be determined by the appropriate start signal, pulse [b] on the stimulation data channel 630 and by the timing of the electrical energy received at the one or more receivers 500.
  • the stimulation pulse is only provided to the electrode 200 #2 if the pulse energy controller 550 is in high-energy mode 550 (triggered by the start pulse [b]) when the energy pulse is received 500.
  • the pulse energy controller 550 After receiving the instructions and/or parameters 630, and/or upon switching the mode 550 to high-power, the pulse energy controller 550 configures itself appropriately:
  • the next pulse depicted is a transmittal on the stimulation data 630 channel indicating that stimulation should start (start signal [b]).
  • start signal [b] the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [c]. - substantially simultaneously with the switch to high-energy mode 550, a pulse [d] of stimulation energy 620 is transmitted.
  • a corresponding pulse [e] is received at the one or more receivers 500. It comprises at least a portion of the electrical energy transmitted 620.
  • each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500
  • the monitored data on the pulse width of that pulse 200 #2 is transmitted 570 as pulse [g]
  • the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [c].
  • pulse [b] After detection of a second start signal, pulse [b], the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the second transition from 0 to 1 of waveform [c], and the cycle of pulses [d], [e], [f], [g] is repeated.
  • the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the second transition from 1 to 0 of waveform [c].
  • pulse [b] After detection of a third start signal, pulse [b], the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the third transition from 0 to 1 of waveform [c], and the cycle of pulses [d], [e], [f], [g] is repeated.
  • the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the third transition from 1 to 0 of waveform [c].
  • the device may operate with relatively low data rates and low communication overheads because there is only a need for a start signal [b] for the transmission/pass-through synchronization.
  • the power efficiency may be higher than configuration 3) as the lower-energy mode 550 is used between pulses, and smaller wake- up times maximizes the time spent in the lower-energy mode 550 over an extended period of operation.
  • the pulse energy controller 550 may be configured and arranged to switch to high-energy mode 550 substantially simultaneously, or immediately before, the receipt of stimulation energy 620 used to generate an electrical stimulation pulse. As no additional instructions and/or parameters 630 need to be read, no additional time must be reserved for interpreting the data and reconfiguring the pulse energy controller 550 before a pulse may be generated.
  • the need for data transfer during operation is reduced, allowing a lower data rate to be utilized. This may reduce the complexity of such a pulse energy controller 550.
  • One of the insights upon which the invention is based is that a more efficient operation is possible if the need for an internal power source is greatly reduced, and the operation of the pulse energy controller 550 is synchronized to a high degree with the transfer of stimulation energy 620 (or the transfer of stimulation energy 620 is synchronized to a high degree with the operation of the pulse energy controller 550). This allows the data rate to be kept within practical levels.
  • an estimation for as suitable data-packet size for configuration 4) may be:
  • the restrictions on pulse duration may mean that it is not possible to communicate a stop instruction before the desired end of a stimulation pulse.
  • the logic control 553 may be advantageously further configured to control pulse duration of the stimulation pulses.
  • a permitted operating frequency such as an ISM band
  • ISM band is used (in-band communication).
  • the ISM radio bands are reserved internationally for industrial, scientific and medical (ISM) purposes other than telecommunications.
  • ISM frequencies include center frequencies 6.78 MHz, 13.56 MHz, 27.12 MHz, and 40.68 MHz providing bandwidths of 30 kHz, 14 kHz, 326 kHz, and 40 kHz, respectively.
  • ISO/IEC 14443 is an international standard that defines proximity (contactless) cards (types A & B) used for identification, and the transmission protocols for
  • the current version (14443-1 :2018, 14443-2:2016; 14443- 3:2018, 14443-4:2018) is available at www.iso.org.
  • the nominal frequency is 13.56 MHz.
  • ISO/IEC 15693 is an international standard for vicinity cards (cards which can be read from a greater distance than proximity cards).
  • the current version (15693-1 :2018, 15693-2:2019; 15693-3:2019) is available at www.iso.org.
  • the nominal frequency is
  • ISO/IEC 18000 is an international standard describing different RFID
  • Zigbee is a communication protocol based on IEEE 802.15.4.
  • the current version (802.15.4-2015) is available at standards.ieee.org.
  • the data rate may also be reduced - this is particularly advantageous when communicating at lower frequencies. For example, frequencies of 100 MHz or less. For example:
  • the required data rate is very low - instructions and/or parameters are transmitted 630 when the stimulation energy 620 is not being transmitted, and the pulse energy controller 550 is not providing stimulation pulses.
  • one data transmission 630 per ten seconds may be sufficient, resulting in a data rate of only a few bits per second.
  • pulse energy controller 550 is highly configurable. For example:
  • a lower level of energy may be transmitted to sustain enough charge in the logic to operate reliably in the lower energy mode 550. This may also improve the responsiveness when the pulse energy controller 550 is switched to high-energy mode 550;
  • - feedback may be provided as transmitted pulses 570 relating to any aspect of the operation. They may be transmitted at particular times of the day. They may provide feedback about each stimulation pulse and/o feedback about a plurality of previous pulses;
  • a pulse energy controller 550 comprises one or more clock generators 553c, configurable as a stimulation pulse timing clock, configured and arranged to influence a temporal characteristic of the one or more electrical stimulation pulses provided to the one or more electrodes 200.
  • the pulse timing clock may be used to further improve the synchronization.
  • the stimulation data 630 may comprise an instruction to set, reset, and/or synchronize one or more clock generators 553c;
  • the energy transmitter 620 and/or data transmitter 630 may be further configured to allow these one or more clock generators to be synchronized with the pulse energy controller 550 - for example, when a first pulse of stimulation data 630 is transmitted or when a first pulse of stimulation energy 630 is transmitted.
  • the stimulation data 630 may comprise an instruction to synchronize a controller 550 clock generator to the data transmitter 630 and/or energy transmitter 620 clock generators;
  • stimulation pulses are only provided to the one or more electrode 200 if the pulse energy controller is in high-energy mode 550 when a stimulation energy pulse is received 500. This may also be advantageous if the pulse energy controller 550 is subjected to other external energy pulses, such as from
  • the pulse energy controller 550 may be switched to high- energy mode 550 in many different ways.
  • a switch to a lower-energy mode 550 may also be initiated under particular conditions and/or if electrical energy with undesired characteristics is detected.
  • the device 100, 150 may be considered to have three main design restrictions:
  • the distal end 100 may be substantially configured and arranged to be implanted proximate the tissue to be stimulated;
  • the proximal end 150 may be substantially configured and arranged to receive 500 electrical energy
  • the device 100, 150 may be optimized to comply with one of the design restrictions, or comprises may be made based on two or more design restrictions.
  • a longer substrate 300 longer lead
  • the proximal end 150 and the receiver 500 of electrical energy may be disposed close to an ear or at the back of the head.
  • the one or more stimulation electrodes 200 may be provided proximate the pulse energy controller 550.
  • FIG. 5 and FIG. 6 depict examples of nerves that may be stimulated using a suitably configured devices 100, 150 with an implantable distal end 100. It may provide neurostimulation to treat, for example, headaches or primary headaches.
  • FIG. 5 depicts the left supraorbital nerve 910 and right supraorbital nerve 920 which may be electrically stimulated using a suitably configured device.
  • Figure 6 depicts the left greater occipital nerve 930 and right greater occipital nerve 940 which may also be electrically stimulated using a suitably configured device.
  • a suitable location is determined to provide the electrical stimulation required for the treatment.
  • Approximate implant locations for the distal part of the stimulation device comprising stimulation devices 100, 150 are depicted as regions:
  • location 810 for left supraorbital stimulation and location 820 for right supraorbital stimulation for treating chronic headache such as migraine and cluster.
  • location 830 for left occipital stimulation and location 840 for right occipital stimulation for treating chronic headache such as migraine, cluster, and occipital neuralgia.
  • these will be the approximate locations 810, 820, 830, 840 for the implantable part of the device 100, 150.
  • a separate stimulation system may be used for each implant location. Where implant locations 810, 820, 830, 840 are close together, or even overlapping, a single stimulation system may be configured to stimulate at more than one implant location 810, 820, 830, 840.
  • a plurality of stimulation devices 100, 150 may be operated separately, simultaneously, sequentially or any combination thereof to provide the required treatment.
  • FIG 7 depict further examples of nerves that may be stimulated using a suitably configured improved stimulation device 100, 150 to provide neurostimulation to treat other conditions.
  • the ability to increase the stimulation current density in transverse directions 720 improves the stimulation along a longitudinal axis of the nerve or nerve branches.
  • the locations depicted in FIG. 5 and FIG. 6 (810, 820, 830, 840) are also depicted in FIG. 7.
  • a suitable location is determined to provide the electrical stimulation required for the treatment.
  • Approximate implant locations for the part of the stimulation device comprising stimulation electrodes are depicted as regions:
  • Parkinson’s disease patients treating dystonia, obesity, essential tremor, depression, epilepsy, obsessive compulsive disorder, Alzheimer’s, anxiety, bulimia, tinnitus, traumatic brain injury, Tourette’s, sleep disorders, autism, bipolar; and stroke recovery
  • vagus nerve stimulation for treating epilepsy, depression, anxiety, bulimia, obesity, tinnitus, obsessive compulsive disorder and heart failure;
  • Other condition that may be treated include gastro-esophageal reflux disease and inflammatory diseases.
  • any electrode 200, 400, 450 may be connected as either a stimulating 200 or return electrode 400, 450. This may be advantageous if it is uncertain whether the implantable distal end is above or below the targeted tissue - for example, above or below a nerve. This may be advantageous if it is uncertain whether the implantable distal end is above or below the targeted tissue - for example, above or below a nerve.
  • controller data transmitter controller data
  • stimulation energy transmitter 620 stimulation energy transmitter, stimulation energy
  • stimulation data transmitter stimulation data
  • location for deep brain stimulation 860 location for vagus nerve, carotid artery, carotid sinus, phrenic nerve or hypoglossal stimulation

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Abstract

In many applications, it is desirable for a stimulation device, typically comprising a therapeutic lead (a lead comprises stimulating electrodes and interconnections), to provide electrical stimulation as effectively as possible. A method of controlling pulse energy of a tissue stimulation device 100, 150 is provided comprising one or more energy receivers 500; a pulse energy controller 550; the device being configured and arranged to switch the pulse energy controller 550 from the lower-energy mode 550 to the high-energy mode 550 when pulse energy is received and to switch from the high-energy mode 550 to the lower-energy mode 550 between individual pulses of the pulse train of energy received. By predetermining the start of the transmission of electrical energy, the stimulation device can accurately determine when it should switch itself to the high-energy mode, allowing it to be ready for operation as quickly as possible. By synchronizing the start of operation, the amount of wasted transmitted energy may be reduced.

Description

AN ELECTRICAL STIMULATION DEVICE WITH SYNCHRONIZED PULSED ENERGY TRANSFER
FIELD
The present disclosure relates to a method of controlling pulse energy of a device for providing electrical tissue stimulation. It also relates to such a stimulation device.
BACKGROUND
Electrical stimulation systems may be used to deliver electrical stimulation therapy to patients to treat a variety of symptoms or conditions such as headaches, lower back pain and incontinence. The system may comprise one or more devices, and be at least partially implantable.
In many electrical stimulation applications, it is desirable for a stimulation device, typically comprising a therapeutic lead (a lead comprises stimulating electrodes and interconnections), to provide electrical stimulation as effectively as possible.
US application US2015/297900 describes a device for providing an implantable lead with wireless energy, the device including; one or more non-inductive antennas substantially enclosed within the housing and configured to receive
electromagnetic energy radiated from a source located outside of the patient's body; and one or more connection pads substantially enclosed within the housing, wherein the connection pads are configured to couple with one or more electrodes in the implantable lead and form an electric connection over which the connection pads provide the extracted excitation waveforms from the electronic circuit to the electrodes in the implantable lead, the implantable lead being separate from the device.
US application US2009/105782 describes methods and implantable apparatus that do not require an onboard, implanted power supply. Power may be supplied from outside of the body by near-field inductive coupling with an external power supply provided in a support article (e.g., garment) worn by the patient. Power may also be supplied by providing an antenna for harvesting ambient RF energy and converting it into DC power. In addition, remote wireless programming of the parameters that specify the nature of current pulses provided is provided. US application US2006/074450 describes implantable stimulation systems comprises two functional modules: i) a programmable pulse generator module, and ii) a stimulus-receiver module. The stimulus-receiver module is designed to provide stimulation/blocking pulses with an external stimulator. An external device acts as a programmer and as an external stimulator. The system uses implantable power source until stable external power is available. A power select circuitry switches between implanted power source and external power source, when its available.
US application US2015/099959 describes an electrode array (10) configured for implantation into a subject. The electrode array (10) includes an organic substrate material (12) configured to be implanted into an in vivo environment and to optionally dissolve after implantation into the in vivo environment and be absorbed by the in vivo environment, and an electrode (14) mounted to the organic substrate material (12) and configured to acquire signals generated by the in vivo environment. A conductive trace (16) is formed between the electrode (14) and the connection pad (2) which includes a conductive ink that is MRI-compatible.
It is an object of the invention to provide a high degree of efficiency in the transmission of the stimulated energy without greatly increasing the complexity of the device.
GENERAL STATEMENTS
According to a first aspect of the present disclosure, there is provided a method of controlling pulse energy of a tissue stimulation device, the tissue stimulation device comprising: one or more energy receivers, configured and arranged to wirelessly receive a pulse train of energy from an associated stimulation energy transmitter when the associated stimulation energy transmitter is proximate; and one or more stimulation electrodes; a pulse energy controller, configured and arranged to receive electrical energy from the one or more energy receivers and to transfer electrical energy as one or more electrical stimulation pulses to the one or more stimulation electrodes; the method comprising: configuring and arranging the pulse energy controller to operate in a high- energy mode, wherein electrical energy is transferable; and in a lower-energy mode, wherein the transfer of electrical energy to one or more stimulation electrodes is restricted; configuring and arranging the stimulation device to detect when first predetermined conditions have been detected whereby the pulse energy controller is switched from the lower-energy mode to the high-energy mode substantially
simultaneously, or immediately before, the receipt of electrical energy, suitable for providing an electrical stimulation pulse, from the one or more energy receivers;
configuring and arranging the stimulation device to detect when second predetermined conditions have been detected whereby the pulse energy controller is switched from the high-energy mode to the lower-energy mode between individual pulses of the pulse train of energy received.
By predetermining the start of the transmission of electrical energy, the stimulation device can accurately determine when it should switch itself to the high- energy mode, allowing it to be ready for operation as quickly as possible. By
synchronizing the start of operation, the amount of wasted transmitted energy may be reduced - energy may be wasted if the electrical energy is being transmitted and the stimulation device is not ready. By switching to the lower-energy mode between individual pulses of the pulse train, the time that the stimulation device is in lower-energy mode may be longer - for example, the electrical interconnections and the stimulation electrodes are only connected when they are needed for actual stimulation, further reducing the risk of timing mismatches and/or unwanted energy storage.
Lower-energy mode consumes substantially less energy than the corresponding high-energy mode - so the controller may conserve energy, and only become active when needed.
The controllers may be configured and arranged to detect predetermined conditions that should be satisfied to switch between the high-energy mode and the lower- energy mode. These predetermined conditions may be pre-programmed (in other words, not transmitted immediately before use using a data receiver). Additionally or
alternatively, one or more parameters may be (re)programmable after receiving one or more instructions.
According to another aspect of the current disclosure, the tissue stimulation device is configured and arranged to monitor electrical energy received from the associated stimulation energy transmitter; and to derive the first and/or second
predetermined conditions from the monitored electrical energy. This is an example of providing the moments in time to switch between modes as appropriate conditions, and configuring the pulse energy controller to evaluate these conditions.
Optionally, the tissue stimulation device is configured and arranged to monitor electrical energy received at the one or more energy receivers.
According to a further aspect of the current disclosure, a stimulation device is provided which further comprises a data receiver, configured and arranged to wirelessly receive, from the one or more energy receivers, stimulation data, the method further comprising: configuring the tissue stimulation device to derive the first and/or second predetermined conditions from an instruction comprised in the stimulation data; and/or configuring the tissue stimulation device to predetermine one or more corresponding characteristics of one or more subsequent electrical stimulation pulses from the stimulation data.
By allowing the device to receive one or more instructions (pre)determining the condition under which the energy mode of the pulse energy controller is switchable and/or one or more characteristics of the energy pulses, a highly configurable device is provided.
According to a yet further aspect of the current disclosure, the pulse energy controller is configured and arranged to provide two or more electrical stimulation pulses after switching from the lower-energy mode to the high energy mode, and before any subsequent receipt of stimulation data.
By configuring the pulse energy controller to provide two or more electrical stimulation pulses as instructed, the data-rate may be kept even lower - repetition of pulses is relatively straightforward to implement in the logic control. In addition, there is still a high degree of customization possible as important parameters determining characteristics of the pulse may still be modified between pulse sequences. The pulse energy controller may also operate more independently - this is particularly useful if data communication is interrupted, or even lost due to interference.
According to a further aspect of the present disclosure, the pulse energy controller further comprises one or more electrode switches, configured and arranged to restrict the transfer of electrical energy to one or more stimulation electrodes when the pulse energy controller is operating in the lower-energy mode. Additionally or alternatively, the stimulation data may comprise an instruction to connect and/or disconnect one or more stimulation electrodes, and the pulse energy controller is configured and arranged to connect and/or disconnect the energy pulse controller through one or more electrical connections to one or more stimulation electrodes as instructed.
By allowing selection (connection) of one or more electrodes, an even further degree of customization is provided as electrical stimulation may be provided to tissue proximate one or more selected stimulation electrodes. In addition, by configuring and arranging the pulse generator to provide disconnection, unwanted energy storage in leads may also be reduced or even eliminated. The selection may be determined by the pulse energy controller. Additionally or alternatively, the stimulation data may comprise one or more instruction about the one or more electrodes to be selected.
According to a still further aspect of the present disclosure, the pulse energy controller further comprises a pulse timing clock, configured and arranged to influence a temporal characteristic of the one or more electrical stimulation pulses provided by the pulse energy controller.
For example, a temporal characteristic may be a stimulation pulse start time, a pulse width and/or a stimulation pulse end time. In other words, the clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced.
According to another aspect of the present disclosure, the pulse energy controller further comprises a mode timing clock, configured and arranged to switch from the high-energy mode to the lower-energy mode and/or from the lower-energy mode to the high-energy mode.
The mode clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced, and the length of time spent in lower-energy mode may be increased.
According to a still further aspect of the present disclosure, the energy transmitter further comprises an energy timing clock, configured and arranged to influence a temporal characteristic of the stimulation energy, the stimulation data comprising an instruction to synchronize one or more timing clocks, and configuring and arranging the pulse energy controller to synchronize the energy timing clock to the pulse timing clock and/or mode timing clock.
For example, a temporal characteristic may be an energy start time, an energy pulse width and/or an energy end time. In other words, the energy clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches may be reduced.
According to another aspect of the present disclosure, a stimulation system is provided comprising: a tissue stimulation device, and a stimulation energy transmitter, configured and arranged according to any of the embodiments described.
A high degree of interoperability and reliability is provided with a matched set of an energy transmitter and a tissue stimulation device.
BRIEF DESCRIPTION OF THE DRAWINGS
Features and advantages of some embodiments of the present invention, and the manner in which the same are accomplished, will become more readily apparent upon consideration of the following detailed description of the invention taken in conjunction with the accompanying drawings, which illustrate preferred and exemplary embodiments, and which are not necessarily drawn to scale, wherein:
FIG. 1A, IB & 1C depict an example of an implantable distal end of a stimulation device;
FIG. 2A, 2B & 2C depict an example of a proximal end of a stimulation device;
FIG. 3 schematically depicts a detailed example of a pulse energy controller;
FIG. 4A, 4B and 4C depict three different data communication and energy transmission signal operating configurations; FIG. 5 and FIG. 6 depict examples of nerves that may be stimulated to treat headaches;
FIG. 7 depicts examples of nerves that may be stimulated for other treatments; and
FIG. 8 depicts examples of data communication and energy transmission signals in an operating configuration.
DETAILED DESCRIPTION
In the following detailed description, numerous non-limiting specific details are given to assist in understanding this disclosure.
In general, stimulation devices described herein may comprise a stimulation energy source and an implantable end - the implantable end comprises one or more stimulation electrodes.“Implantable end” means that at least this section of the stimulation system is configured and arranged to be implanted. Optionally, one or more of the remaining sections of the stimulation systems may also be configured and arranged to be implanted.
FIG. 1A, IB & 1C depict longitudinal cross-sections through a first embodiment 100 of an implantable distal end of a stimulation device comprising:
- an elongated substrate 300, disposed along a longitudinal axis 700, the substrate having a first 310 and second 320 surface disposed along substantially parallel transverse planes 700, 720. As depicted, the first surface 310 lies in a plane comprising the longitudinal axis 700 and a first transverse axis 720 - the first transverse axis 720 is substantially perpendicular to the longitudinal axis 700. As depicted, the plane of the first surface 310 is substantially perpendicular to the plane of the cross-section drawing (substantially perpendicular to the surface of the paper). The substrate 300 has a thickness or extent along a second transverse axis 750 - this second transverse axis 750 is substantially perpendicular to both the longitudinal axis 700 and the first transverse axis 720 - it lies in the plane of the drawing (along the surface of the paper) as depicted. The first surface 310 is depicted as an upper surface and the second surface 320 is depicted as a lower surface. To clarify the different views, the axes are given nominal directions:
- the longitudinal axis 700 extends from the proximal end (not depicted) on the left, to the distal end, depicted on the right of the page;
- the first transverse axis 720 extends into the page as depicted; and
- the second transverse axis 750 extends from bottom to top as depicted.
For example, the elongated substrate 300 may comprise an elastomeric distal end composed of silicone rubber, or another biocompatible, durable polymer such as siloxane polymers, polydimethylsiloxanes, polyurethane, polyether urethane, polyetherurethane urea, polyesterurethane, polyamide, polycarbonate, polyester, polypropylene,
polyethylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene, polysulfone, cellulose acetate, polymethylmethacrylate, polyethylene, and polyvinylacetate. Suitable examples of polymers, including LCP Liquid Crystal Polymer), are described in “Polymers for Neural Implants”, Hassler, Boretius, Stieglitz, Journal of Polymer Science: Part B Polymer Physics, 2011, 49, 18-33 (DOI 10.1002/polb.22169), In particular, Table 1 is included here as reference, depicting the properties of Polyimide (UBE U-Vamish-S), Parylene C (PCS Parylene C), PDMS (NuSil MED- 1000), SU-8 (MicroChem SU-8 2000 & 3000 Series), and LCP (Vectra MT1300).
Flexible substrates 300 are also preferred as they follow the contours of the underlying anatomical features very closely. Very thin substrates 300 have the additional advantage that they have increased flexibility.
Preferably, the flexible substrate 300 comprises an LCP, Parylene and/or a Polyimide. LCP’s are chemically and biologically stable thermoplastic polymers which allow for hermetic sensor modules having a small size and low moisture penetration.
Advantageously, an LCP may be thermoformed allowing complex shapes to be provided. Very thin and very flat sections of an LCP may be provided. For fine tuning of shapes, a suitable laser may also be used for cutting. For example, LCP substrates 300 with thicknesses (extent along the second transverse axis 750) in the range 50 microns (um) to 720 microns (um) may be used, preferably 100 microns (um) to 300 microns (um). For example, values of 150 um (micron), lOOum, 50um, or 25um may be provided. Similarly, substrate widths (extent along the first transverse axis 720) of 2mm to 20 mm may be provided using LCP, for example. At room temperature, thin LCP films have mechanical properties similar to steel. This is important as implantable substrates 300 must be strong enough to be implanted, strong enough to be removed (explanted) and strong enough to follow any movement of the anatomical feature and/or structure against which it is implanted.
LCP belongs to the polymer materials with the lowest permeability for gases and water. LCP’s can be bonded to themselves, allowing multilayer constructions with a homogenous structure.
In contrast to LCP’s, polyimides are thermoset polymers, which require adhesives for the construction of multilayer substrates. Polyimides are thermoset polymer material with high temperature and flexural endurance.
An LCP may be used, for example, to provide a substrate having multilayers (not depicted) - in other words, several layers of 25 um (micron) thickness. Electrical interconnect layers may also be provided by metallization using techniques from the PCB (Printed Circuit Board) industry, such as metallization with a bio-compatible metal such as gold, silver or platinum. Electro-plating may be used. These electrical interconnect layers may be used to provide electrical energy to any electrodes.
Preferably, a low aspect ratio is used for the elongated substrate to reduce the chance of implantation problems - for example a ratio of height (thickness or extent along the second transverse axis 750) to width (extent along the first transverse axis 720) of less than 10, such as 0.3mm high and 10mm wide.
Although depicted as a substrate 300 with a substantially rectangular cross- section, substrates (and leads) having other cross-sections, such as square, trapezoidal may be used. The cross-section shape and/or dimensions may also vary along the longitudinal axis 700. Alternatively a substrate may be used with a substantially circular (which includes a circle, a flattened circle, a stadium, an oval and an ellipse) transverse cross-section - this may also be described as tubular or cylindrical.
The distal end 100 of the device depicted in FIG. 1 further comprises:
- a stimulation electrode 200, comprised in the second surface 320 and configured to transmit energy, in use, to human or animal tissue (after implantation). In this example, it is electrical energy. The stimulation electrode 200 has a longitudinal extent along the longitudinal axis 700 and a transverse extent along a first transverse axis 720, the transverse axis 720 being substantially perpendicular to the longitudinal axis 700 and substantially parallel to the second surface 320.
“Comprised in the second surface” means that stimulation electrode 200 is relatively thin, and attached to the second surface 320. The electrode 200 may also be embedded in the second surface 320.
In general, one or more stimulation electrodes 200 may be provided. The number, dimensions and/or spacings of the stimulating electrodes 200 provided in the distal end 100 may be selected and optimized depending on the treatment - for example, if more than one electrode 200 is provided, each electrode 200 may provide a separate stimulation effect, a similar stimulation effect or a selection may be made of one or two electrodes 200 proximate the tissues where the effect is to be created. The electrodes 200 may comprise a conductive material such as gold, silver, platinum, iridium, and/or
platinum/iridium alloys and/or oxides.
FIG. IB depicts a stimulation electrode 200, elongated along the longitudinal axis 200. Although an oval cross-section is suggested in FIG. 1 A and IB, any shape may be used, such a square, rectangular, triangular, polygonal, circular, elliptical, oval, and round. An elongated electrode (or strip electrode) may also be used.
The distal end 100 of the device of FIG 1 further comprises:
- optionally, one or more return (or ground) electrode 400, configured to provide, in use, a corresponding electrical return for one or more stimulation electrodes 200. In other words, the electrical return 400 closes the electrical circuit. Any suitable
configuration and arrangement may be provided. Additionally or alternatively, one or more return (ground) electrodes may be provided:
- proximate the one or more electrodes 200, at a distal end 100 of the device;
- proximate a source of electrical energy (not depicted, see below), at a proximal end of the device;
- comprised in the first surface 310;
- comprised in the second surface 320;
and any combination thereof.
In some descriptions of conventional stimulation devices, the return electrode may be referred to as an anode. Traditionally, this has been provided via the housing of an IPG (Implantable Pulse Generator). Stimulation electrodes may similarly be referred to as cathodes.
The one or more return electrodes 400 may comprise a conductive material such as gold, silver, platinum, iridium, and/or platinum/iridium alloys and/or oxides.
A distal end (or lead) 100 suitable for implant may comprise, for example, 12 stimulation electrodes over a length of 15cm. A stimulation electrode may have dimensions in the order of 6 to 8 mm along the longitudinal axis 700 and 3 to 5 mm along the first transverse axis 720, so approximately 18 to 40 square mm (mm2). If a strip of 4 mm wide (extent along the first transverse axis 720) is provided as a return electrode, then a length (extent along the longitudinal axis 700) 4.5 to 10 mm also provides a tissue contact-area of 18 to 40 square mm (mm2).
The distal end 100 of the device of FIG 1 further comprises:
- one or more electrical interconnections 250 may also be provided configured to provide the electrode 200 with electrical energy. They may be comprised in the first surface 310, the second surface 320, in the substrate between the surfaces 310, 320, and any combination thereof.
Additionally or alternatively, the substrate 300 may be a multilayer, comprising one or more electrical interconnection layers to provide the electrode 200 with electrical energy. In use, the electrical interconnections are connected to a source of electrical power (not depicted). If an LCP multilayer is used, the thickness (extent of the substrate 300 along the second transverse axis 750 or the perpendicular distance between the first surface 310 and the second surface 320) may be typically approximately 150 um (micron) in the sections with no electrodes 200 or interconnections, 250 um in the sections with an electrode 200, and 180 um in the sections with an electrical interconnection 250. If multilayers are used, electrical interconnection layers of 25 um (micron) may be used, for example.
FIG. IB depicts a view of the second surface 320 of the implantable distal end 100 of the device depicted in FIG. 1 A. In other words, the second surface 320 is depicted in the plane of the paper, lying along the longitudinal axis 700 (depicted from bottom to top) and in the first transverse axis 720 (depicted from left to right). The second transverse axis 750 extends into the page. This is the view facing the animal or human tissue which is stimulated (in use). The first surface 310 is not depicted in FIG. IB, but lies at a higher position along the second transverse axis 750 (into the page), and is also substantially parallel to the plane of the drawing.
The substrate 300 extends along the first transverse axis 720 (considered the width of the distal end 100 of the stimulation device) between two extents.
The distal end 100 of the device may be implanted by first creating a tunnel and/or using an implantation tool.
The one or more return electrode 400 is depicted in FIG. 1 A and 1C, but not in FIG IB.
After implantation of the distal end 100 of the device, a source of energy may be configured and arranged to provide, in use, electrical energy to the stimulation electrode 200 with respect to the electrical return applied to the one or more return electrode 400.
This source of electrical energy may be, for example, disposed at a proximal end of the stimulation device:
- an energy source, such as a pulse generator (not depicted, see below), directly connected to the one or more interconnections 250;
- one or more energy receivers (not depicted, see below), such as one or more conductors, directly connected to the one or more interconnections 250. The one or more conductors, such as coils with one or more windings, being configured to wirelessly receive energy from an energy source, such as a wireless pulse generator (not depicted, see below). A coil with one or more windings may also be described as an inductive antenna.
FIG. 2A, 2B & 2C depict longitudinal cross-sections through a first embodiment 150 of a proximal end of a stimulation device 100, 150. In this example, the proximal end 150 comprises the same features as depicted in FIG. 1: - the elongated substrate 300, disposed along the longitudinal axis 700, with the first 310 and second 320 surfaces;
- the first transverse axis 720 extends into the page as depicted, and the second transverse axis 750 extends from bottom to top as depicted;
- the longitudinal axis 700 extends from the proximal end 150 on the left, to the distal end 100, towards the right of the page.
The dimensions of the substrate 300 (extent along the first transverse axis 720 or width, extent along the second transverse axis 750 or thickness) at the distal 100 and proximal end 150 are depicted as approximately the same. This is convenient if the device 100, 150 comprises the same substrate 300, allowing it to be made from a single piece of material - this is advantageous if the distal end 100 of the device is substantially completely implanted as this may reduce the risk of fluid ingress into the device.
The proximal end 150 of the device further comprises:
- one or more energy receivers 500, configured and arranged to wirelessly receive energy from an associated stimulation energy transmitter 620 when the associated stimulation energy transmitter 620 is proximate. As depicted, the one or more energy receivers 500 are comprised in the first surface 310. Alternatively or additionally, the one or more energy receiver 500 may be comprised in the second surface 320 and/or between the first 310 and second surface 320. It may be advantageous to embed the one or more energy receivers 500 into the substrate 300 to resist the ingress of fluids and/or a coating may be applied on top of the one or more energy receivers 500.
- a pulse energy controller 550, configured and arranged to receive electrical energy from the one or more energy receivers 500. It is further configured and arranged to provide stimulation energy through the one or more electrodes 200 as one or more electrical pulses. This changes the electrical potential and/or current applied to the one or more electrodes 200. The pulse energy controller 550 may be connected to the one or more electrodes 200 through one or more interconnections 250. It may be further connected the one or more energy receivers 500 through one or more further
interconnections 250.
As depicted, the pulse energy controller 550 is comprised between the first 310 and second surface 320. It may be advantageous to embed the pulse energy controller 550 into the substrate 300 to resist the ingress of fluids and/or a coating may be applied on top of one or more components of the pulse energy controller 550. This may also provide an additional protection layer for tissue from any electrical potentials present in the pulse energy controller 550. Alternatively, the pulse energy controller 550 may be comprised in the second surface 320 or the first surface 310.
- optionally, one or more return (or ground) electrode 450, configured and arranged to provide, in use, a corresponding electrical return for one or more stimulation electrodes 200 which receive stimulation energy from the pulse energy controller 550. In other words, the electrical return 450 closes the electrical circuit. Any suitable configuration and arrangement may be provided - for example, as depicted, comprised in the second surface 320, proximate the pulse energy controller 550. Additionally or alternatively, one or more return (ground) electrodes 450 may be comprised in the first surface 310. As explained above, a combination of one or more return electrodes 450 proximate the pulse energy controller 550 and one or more return electrodes 400 proximate the stimulation electrodes 200 may also be provided.
As will be described below, one or more stimulation electrodes 200 may be configured to be selectable by connecting or disconnecting the electrode 200 and/or a suitable interconnection 250. Additionally or alternatively, one or more return electrodes 400, 450 may similarly be configured to be selectable by connecting or disconnecting the return electrode 400, 450 and/or a suitable interconnection 250.
Additionally or alternatively, an electrode 200, 400, 450 may be configurable (selectable) as a stimulation or return electrode - electrically, there is no substantial difference between a stimulation electrode 200 and a return electrode 400, 450. In practice, it may be advantageous to include a blocking capacitor in an electrical connection to a return electrode 400, 450 - this may also be configured to be selectable. An associated stimulation energy transmitter 620 is configured and arranged to wirelessly transmit stimulation energy. Any suitable energy transmitter may be used, such as:
- one or more coils, configured and arranged to convert the energy pulses to electromagnetic pulses for transmission;
- one or more lasers, LED’s or laser diodes, configured and arranged to convert the energy pulses to light pulses for transmission;
- one or more electromagnetic transducers, configured and arranged to convert the energy pulses to electromagnetic radiation pulses for transmission, such as RF (radio-frequency) or microwaves;
- one or more acoustic transducers, configured and arranged to convert the energy pulses to acoustic pulses for transmission, such as ultrasound;
- one or more electrical capacitive conductors, configured and arranged to convert the energy pulses to electrical field pulses for transmission.
Combinations of these transmitter types may also be used. The transmitter components may be miniaturized using modem manufacturing technology. These technologies comprise at least one conductor.
As depicted, an associated stimulation data transmitter 630 may also be provided, configured and arranged to instruct the tissue stimulation device 100, 150 how, where and when it should stimulate tissue by transmitting (providing) one or more parameters and/or one or more instructions as stimulation data 630. Any suitable energy transmitter types (as indicated above for the stimulation energy transmitter 620 may be used. When used for data, security and safety issues may limit the choice, or require additional measures.
- with light, there are no major bandwidth and/or data rate issues;
- with electromagnetic signals, such as RF (radio -frequency) or
microwaves, there are also no major bandwidth and/or data rate issues. However, there may be some legal restrictions, such as the available frequency bands (e.g. the ISM bands);
- acoustic and capacitive types may be limited in some configurations due to technical difficulties in achieving a relatively bandwidth and/or data rate.
It may be advantageous to use a separate stimulation data transmitter 620 and stimulation energy transmitter 630, as that allows each one to be optimized separately. Alternatively, the transmitters 620, 630 may be combined in the same device, sharing one or more components. Energy and data may be transmitted via the same channel, or separate channels may be provided. If using the same channel, the data may be transmitted substantially simultaneously as any energy, or substantially not
simultaneously. The stimulation transmitters 620, 630 may also comprise one or more components providing some degree of logic control and/or processing such that the tissue stimulation device 100, 150, and in particular the pulse energy controller 550, may be instructed in a more extensive way. Any suitable energy receiver 500 may be used, including the types indicated as examples of energy transmitters 620. Preferably, the same or a similar type is used to provide a high degree of efficiency in the transmission of the stimulation energy 620. For example, photo-diodes may be used to convert incoming photons to electrical energy, coils may be used to convert magnetic energy to electrical energy, piezo-sensitive element may be used to convert acoustic energy to electrical energy. These technologies comprise one or more conductors.
The functions comprised in the pulse energy controller 550, the separation into functional units, and the components used in each functional unit may be any suitable mix to perform the required functions. In terms of the invention, during stimulation operation, the pulse energy controller 550 receives at least a portion of wirelessly -transmitted stimulation energy 620. The pulse energy controller 550 then transfers at least a portion of the received electrical energy to one or more stimulation electrodes 200 as one or more electrical stimulation pulses.
The pulse energy controller 550 is further configured and arranged to operate in:
- a high-energy mode 550, wherein electrical energy is transferrable; and
- a lower-energy mode 550, wherein the transfer of electrical energy to one or more stimulation electrodes 200 is restricted.
The stimulation device 100, 150 is configured and arranged to switch the pulse energy controller 550 under predetermined conditions from the lower-energy mode 550 to the high-energy mode 550 and/or to switch from the high-energy mode 550 to the lower- energy mode 550.
The pulse energy controller 550 is further configured and arranged:
- to detect when the predetermined conditions have been detected;
- to switch from the lower-energy mode 550 to the high-energy mode 550 and/or to switch from the high-energy mode 550 to the lower-energy mode 550; and
- to subsequently provide one or more electrical stimulation pulses to one or more stimulation electrodes 200 in the high-energy mode 550. By providing a pulse energy controller with a high-energy and lower-energy modes, and configuring it to switch to the high-energy mode under predetermined conditions, the pulse energy controller may conserve energy and only become active when needed. By providing a degree of independent control to the pulse energy controller, the need for data transfer during operation is reduced, allowing a lower data rate to be utilized. This may reduce the complexity of the pulse energy controller.
However, the possibility to provide a high degree of customization is maintained due to the ability to read transmitted data.
The device 100, 150 may be configured and arranged before use to determine the conditions (predetermined conditions) under which the pulse energy controller 550 switches from the lower-energy mode 550 to the high-energy mode 550. This may be, for example, a certain period of time after energy signals with particular characteristics were detected. For example, detecting a level of energy within a particular time.
Additionally or alternatively, the data receiver 553 may be further configured and arranged to wirelessly receive, from the one or more energy receivers 500, stimulation data 630 comprising an instruction predetermining conditions for the pulse energy controller 550 to switch from the lower-energy mode 550 to the high-energy mode 550 and/or to switch from the high-energy mode 550 to the lower-energy mode 550.
The pulse energy controller 550 may, for example, comprise a suitably configured and programmed processor, controlling one or more parameters of the stimulation energy pulses, such as an intensity, a duration, a waveform shape, a frequency, and a repetition rate using one or more software or firmware methods. Additionally or alternatively, a hardware-based solution may be used, such as a state-machine implemented in an ASIC (Application-Specific Integrated Circuit).
It may operate in a stand-alone mode, or it may be in regular communication with an external controller, or some combination thereof.
FIG. 3 schematically depicts a detailed example of a suitable pulse energy controller 550. It comprises the following non-limiting examples of four main functional units
1) an interface configured and arranged to receive electrical energy from the one or more energy receivers 500 and to transfer electrical energy to the power supply 551. For example, the one or more energy receivers 500 may disposed at a convenient position to receive electrical energy from the stimulation energy transmitter 620. One or more electrical interconnections 250 may be provided between the one or more energy receivers 500 and the interface. One or more tuning components 500a, such as inductors and/or capacitors, may be provided to increase the efficiency of the stimulation energy transfer between the one or more energy transmitters 620 and the one or more energy receivers 500 and/or to increase the efficiency of stimulation energy transfer between the one or more energy receivers 500 and the
Additionally or alternatively, one or more energy receivers 500 may be comprised within the pulse energy controller 550.
2) a power supply 551, configured and arranged to provide voltages and/or currents to power electronic and electrical components comprised in one or more of the functional units of the pulse energy controller 550. It is further configured and arranged to provide stimulation energy, suitable for tissue stimulation, to the one or more electrodes 200
For example, it may comprise a rectifier 551a to receive electrical energy from the one or more energy receivers 500 and to provide high voltage to a high voltage output 552. Optionally, one or more high voltage buffers 551b may also be connected to this high voltage. Optionally, a high voltage monitor 551c may be connected to the high voltage. High voltage means a voltage range typically used for stimulation voltages. In the context of this disclosure, it is high compared to the voltage used for logic circuits. A low voltage regulator 55 Id, such as a Low-Dropout Regulator (LDO), may be used to provide a regulated low voltage to the Logic Control 553. Optionally, one or more low voltage buffers 55 le may also be connected to this low voltage.
3) a high voltage output 552, configured and arranged to transfer stimulation energy from the power supply 551 to the one or more electrodes 200, preferably as pulses. This may also be described as generating one or more stimulation pulses.
For example, it may comprise a current source 552a, connected to the high voltage. Optionally, a current monitor 552b may be connected to measure the output of the current source 552a and/or one or more current monitors 552b may be connected to measure the current to one or more electrodes 200. One or more electrode switches 552c, having a connect and/or disconnect function, may be provided to allow the one or more electrodes 200 to receive energy individually or in combination with one or more of the other electrodes 200, 400, 450.
The one or more electrode switches 552c may be used to disconnect one or more electrodes 200 and/or one or more interconnections 250 to the electrodes 200 when the pulse energy controller 550 is switched to lower-energy mode 550.
The energy may be provided to pairs of electrodes 200 as differential potentials and/or currents. Additionally or alternatively, one or more of the electrodes 200 may be configured as a return (or ground) electrode. Additionally or alternatively, one or more return electrodes 400, 450 may be used as described above. Optionally, one or more capacitors 400b may be used to block any degree of unwanted DC component in the return connections. Optionally, one or more interconnections 250 may be provided between the high voltage output 552 and the one or more electrodes 200 and/or the one or more return electrodes 400, 450.
4) a logic control 553, configured and arranged to control the transfer of the stimulation energy from the one or more energy receivers 500 to the one or more electrodes 200, 400, 450. For example, it may comprise one or more controllers 553d, connected to the one or more electrode switches 552c, one or more clock generators 553c, a modulator 553a and a demodulator 553b.
The one or more controllers 553d are configured and arranged to provide one or more of the following functions:
- to read, reset, set and/or synchronize the one or more clock generators 553c. Optionally, the one or more clock generators 553c are configured and arrange to receive one or more parameters and/or instructions from the stimulation data 630. For example, they may be in direct or indirect connection with the interface and/or with the
demodulator 553b;
- to detect predetermined conditions that should be satisfied to switch between the high-energy mode 550 and the lower-energy mode 550. These conditions may be pre programmed (in other words, not transmitted immediately before use using a data receiver). Additionally or alternatively, one or more parameters may be (re)programmable after receiving one or more instructions;
- to receive one or more parameters and/or instructions from the stimulation data 630. For example, they may be in direct or indirect connection with the interface and/or with the demodulator 553b. These parameters and/or instructions may be pre
programmed (in other words, not transmitted immediately before use using a data receiver). Additionally or alternatively, one or more parameters and/or instructions may be (re)programmable after receiving one or more parameters and/or instructions;
- to control the operating mode 550 of the pulse energy controller 550 by switching it between the high-energy mode 550 and the lower-energy mode 550;
- to control the functionality and/or components that are enabled or disabled when switching between the high-energy mode 550 and the lower-energy mode 550;
- to control one or more characteristics of the stimulation pulses provided to the one or more electrodes 200
- to control whether one or more electrode 200 is electrically connected to the pulse energy controller 550. For example, they may be in direct or indirect connection with the one or more electrode switches 552c;
- to control whether one or more electrode 200, 400, 450 are operated as a stimulation electrode 200 and/or a return electrode 400, 450;
- to monitor one or more parameters relating to the operation of the pulse energy controller 550, such as one or more currents, voltages, energies, powers;
- to transmit data, such as monitored data. For example, they may be in direct or indirect connection with the interface and/or the modulator 553a;
- to store data, such as monitored data. For example, they may be in direct or indirect connection with a digital memory storage.
Optionally, the pulse energy controller 550 may further comprise one or more measurement components, such as the high voltage monitor 551c and the stimulation current monitor 552b. These are configured and arranged to detect and/or monitor one or more parameters relating to the operation of the pulse energy controller 550. These may be provided to the controller 553d and/or modulator 553a so that the data may be stored and/or transmitted.
Additionally or alternatively, the one or more parameters being monitored may provide an indication of the stimulation energy received in the pulse energy controller 550, either at a particular moment and/or over a period of time. The data from such monitoring may be stored in suitable memory comprised in the pulse energy controller 550, and/or transmitted to an external storage.
The skilled person will realize that the data transmitter 630 may optionally also be configured as a receiver for such monitoring data and the receiver 500 may also be configured as a transmitter for this monitoring data. Additionally or alternatively, the pule energy controller 550 may comprise a separate monitoring transmitter.
In general, the pulse energy controller 550 is configured and arranged to provide the required stimulation energy pulses at the electrodes 200, 400, 450 in co-operation with the stimulation energy transmitter 620.
A dedicated kit may be provided of a cooperating stimulation energy transmitter 620 and a pulse energy controller 550. Optionally, a cooperating stimulation energy transmitter 620 may be also configured and arranged to provide instructions to a tissue stimulation device 100, 150 as stimulation data 630. In other words, a cooperating stimulation energy transmitter 620 may comprise a cooperating stimulation data transmitter 630.
Alternatively, a dedicated kit may be provided of a cooperating stimulation transmitter 620, a cooperating stimulation data transmitter 630 and a pulse energy controller 550.
Additionally or alternatively, a pulse energy controller 550 may be configured to co-operate with a plurality of different stimulation energy transmitters 620. Additionally or alternatively, a stimulation energy transmitter 620 may be configured to co-operate with a plurality of different pulse energy controllers 550. Co-operation may be arranged by standardization and/or customization of one or more components.
Additionally, the pulse energy controller 550 may be further configured and arranged to receive parameters and/or instructions from a user interface.
Additionally or alternatively, a pulse energy controller 550 may be configured to co-operate with a plurality of different stimulation data transmitters 630. Additionally or alternatively, a stimulation data transmitter 630 may be configured to co-operate with a plurality of different pulse energy controllers 550. Co-operation may be arranged by standardization and/or customization of one or more components. Allowing more than one co-operating stimulation transmitter 620, 630 may allow a healthcare professional to operate a pulse energy controller 550 in extensive, therapeutic and/or experimental ways, and the human or animal may have their own stimulation transmitter 620, 630 with more limited (everyday) functions.
Additionally or alternatively, a stimulation data transmitter 620 may be comprised in a mobile device, such as a mobile telephone. Additionally or alternatively, a monitoring data receiver may be comprised in sch a mobile device.
The pulse energy controller 550 is configured and arranged to receive stimulation data 630 comprising one or more parameters which predetermine one or more
corresponding characteristic of one or more electrical stimulation pulses, and/or comprising one or more instructions. These may be, for example:
- directly-appli cable parameters, relating to a characteristic of the operation of the pulse energy controller 550 and/or the one or more stimulation pulses;
- indirectly-applicable parameters, used by logic to determine a characteristic of the operation of the pulse energy controller 550 and/or the one or more stimulation pulses, or for storage. For example, a serial number of a transmitter may be provided - although the logic may be configured and arranged to only accept instructions from certain serial numbers (whitelist), in other configurations the serial number may be stored in an operation log; and
- a direct instruction, relating to a characteristic of the operation of the pulse energy controller 550 and/or the one or more stimulation pulses.
Such parameters and/or instructions which may be received in the stimulation data 630 may include:
- a pulse amplitude, a pulse width, a period, a duty cycle, a number of pulses to be provided, a number of pulses to be repeated, a duration of pulses, a start time, an end time: for example, relating to one or more stimulation pulses to be provided to one or more electrodes, to a positive or negative phase in the pulse train, to one or more pulses of the transmitted stimulation energy 620 to be expected;
- a switch from higher-energy mode 550 to low-energy mode 550, a switch from low energy mode 550 to higher-energy mode 550: for example, the conditions to be met for a switch, a time indication of when a switch is to take please, a period of time that the pulse energy controller 550 is to be kept in that mode 550;
- selection of one or more electrodes 200, 400, 450, a selection of one or more electrodes as a return electrode 200, 400, 450;
- a timing clock synchronization, a timing clock set, a timing clock reset; and
- handshake data, anti-collision data, encryption data, identification data, error detection data, CRC data.
The parameters may represent absolute values, such as pulses of 200 millisecond, or relative (delta) values, for example +50%, +100 millisecond etc.
For example, therapy (treatment) pulses for stimulation provided to the electrodes 200 may be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz. For treatment of pain using Peripheral Nerve Stimulation (PNS), suitable pulse parameters may be: 0 - 10 Volt, in particular 0.5 - 4.0 Volt, amplitude, 0 - 10 mA, 90 - 200 microseconds pulse width and 50 - 400 Hz repetition rate.
It will be obvious to the skilled person that in configurations where there is a relatively high degree of synchronization, such as configuration 3) and 4), pulses received at the one or more energy receivers 500, may also be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz.
Similarly, in configurations where there is a relatively high degree of
synchronization, such as configuration 3) and 4), pulses transmitted by the stimulation energy transmitter 620, may also be 100 microsecond to 1 millisecond wide, and repeated with 40 to 1000 Hz
FIG. 8 depicts examples of data communication and energy transmission signals. These are provided as non-limiting examples to illustrate the operation of the stimulation device 100, 150 in a first configuration - configuration 1).
A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation data 630, stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to the second electrode 200 # 2, and data (feedback) 570 transmitted using, for example, a modulator 553a. Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right. During a particular period of time, the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2. This is indicated as pulse [b].
In this case, the pulse energy controller 550 starts on the left-hand-side (time = 0) in lower-energy mode 550, as indicated by the pulse energy controller 550 waveform being 0.
In this example of a lower-energy mode 550, the logic control listens for stimulation data 630 being transmitted.
The first pulse to occur, starting on the left-hand side, is a pulse [a] of transmitted stimulation data 630 comprising one or more parameters and/or instructions. In this case, for example:
- an instruction for the pulse energy controller 550 to switch from the lower- energy mode 550 to the high-energy mode 550 at tl;
- an instruction for the pulse energy controller 550 to switch from the high-energy mode 550 to the lower-energy mode 550 at t2;
- an instruction to enable transfer of electrical energy from the one or more receivers 500 to electrode number 2 (200 #2) during the high-energy mode 550;
- an instruction that while the pulse energy controller 550 is in high-energy mode 550, a pass-through functionality is to be used. In other words, the timing of the electrical energy pulses received at the one or more receivers 500 determines to a substantially high degree the timing of the stimulation pulses provided to the selected electrode number 200 #2
- one or more parameters indicating a maximum energy for each electrical stimulation pulse provided to electrode 200 #2;
- an instruction, that the average peak current is monitored, and just before the pulse energy controller 550 switches back into low energy mode 550, the data is to be transmitted back by the pulse energy controller. The pulse energy controller 550 comprises a timer or clock, such as a clock generator 553c configured to act as mode timing clock. The instruction may indicate, for example, absolute times to switch mode (tl and t2), and/or relative times (for example from the transmission of the data 630).
After receiving the instructions and/or parameters 630, the pulse energy controller 550 configures itself appropriately:
- it enables electrical energy transfer from the one or more receivers 500 to electrode 200 #2;
- it sets a maximum energy for each stimulation pulse 200;
- it enables switching from high-energy mode 550 to lower-energy mode 550 after generating a train of stimulation pulses;
- it enables the monitoring of the average peak current; and
- it schedules transmission of the monitored data just before t2.
One or more of these configurations may be performed immediately. Alternatively or additionally, one or more of these configurations may be scheduled to be performed immediately upon the switching of the mode 550 to high-power mode 550.
At time tl, the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [b], and waits for the electrical energy to arrive.
- three pulses of electrical energy [c], [d], [e] are transmitted 620.
- three corresponding pulses [f], [g], [h] at substantially the same moment in time are received at the one or more receivers 500. Each pulse at the one or more receivers 500 comprises at least a portion of the electrical energy transmitted 620.
- three corresponding stimulation pulses [i], [j], [k] at approximately the same moment in time are provided to electrode 200 #2. In this case, the energy in each pulse [i], [j], [k] has been limited. Each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500. - after receiving the last pulse [h] at the one or more receivers 500, the monitored data is transmitted 570 as pulse [1]
- at time t2, the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [b].
So, the pulse energy controller 550 is configured and arranged to switch from the lower-energy mode 550 to the high-energy mode 550 immediately before the receipt of electrical energy at the one or more energy receivers 500.
By predetermining the start of the transmission of electrical energy, the stimulation device 100, 150 in general, and the pulse energy controller 550 in particular, may accurately determine when it should switch itself to the high-energy mode 550, allowing it to be ready for operation as quickly as possible. This is possible because of the high degree of independent control. In some configurations, the pulse energy controller 550 may even switch from the lower-energy mode 550 to the high-energy mode 550 substantially simultaneously with the receipt of electrical energy at the one or more energy receivers 500.
By synchronizing the start of operation, the amount of wasted transmitted energy may be reduced - energy may be wasted, for example, if the electrical energy is being transmitted 620 and the stimulation device 100, 150 is not ready. Also the time that the stimulation device 100, 150 is in lower-energy mode 550 may be longer - for example, the electrical interconnections 250 and the stimulation electrodes 200 are only connected when they are needed for actual stimulation, further reducing the risk of timing mismatches and/or unwanted energy storage.
The operation and signals depicted in FIG. 8 may be modified, depending on the configuration of the pulse energy controller 550. For example, if a lower degree of customization is required (standard operating configurations), the pulse energy controller 550 may be configured to operate in substantially the same way for an extended period of time.
For example, modifying of one or more characteristics of the stimulation pulses provided to the one or more electrodes 200 may only be required once per hour or a few times per day, allowing the configuration to remain the same for a relatively large number of pulses.
So for the example depicted in FIG. 8, the following characteristics may be fixed for night time:
- enable electrical energy transfer to electrode 200 #2;
- a maximum energy for each stimulation pulse 200;
- monitoring of the average peak current; and
- transmission of the monitored data just before t2.
In addition, if the number and timing of stimulation energy pulses to be provided remain substantially the same, then t2 - tl remains substantially the same for this extended period.
In such a case, the only instruction and/or parameter required in the stimulation data 630 is the time to switch to high-energy mode tl . Either the time tl is required, or conditions that the pulse energy controller 550 may evaluate to determine tl (the switch to high-energy mode 550) are required.
For configuration 1), advantageously, the data rate and communication overhead are relatively low, and the power efficiency is relatively high. The accurate timing of the high-energy mode 550 means that the length of time in the lower-energy mode 550 may be optimized. In particular, the pulse energy controller can be switched into high-energy mode 550 at an exact time, reducing the risk that the one or more stimulation pulses 620 is wholly or partially missed. In addition, feedback data 570 may be sent at a convenient point during the operation
A different standard operating configuration may then be provided at dawn the next day. These standard operating configurations may be provided in a library comprised in the pulse energy controller 550 and simply selected with an appropriate instruction. Additionally or alternatively, the parameters for the operating configuration to be used during a subsequent period of time may be transmitted as described above and stored in the pulse energy controller 550. In general, high-energy mode 550 is an operating mode 550 in which at least a portion of the electrical energy is transferrable from the one or more energy receivers 500 to one or more stimulation electrodes 200 as one or more electrical stimulation pulses. This may be considered to be the normal operating mode 550. In general, lower-energy mode 550 is a hibernating mode 550 when compared to the normal operating mode 550, wherein the transfer of electrical energy to one or more stimulation electrodes 200 is restricted. In high-energy mode 550, the transfer of electrical energy to these one or more electrodes 200 is not restricted, or at least substantially less restricted. Lower-energy mode 550 consumes substantially less energy than the corresponding high-energy mode 550 - so the controller 550 may conserve energy, and only become active when needed.
For example, one or more of the following measures may be taken to reduce energy consumption:
- the one or more electrodes 200 and interconnections 250 which are scheduled to be connected in high-energy mode 550 may be disconnected using the corresponding electrode switch 552c;
- logic may be switched to a low energy mode 550, such as a lower low voltage and/or lower operating clock frequency;
- logic and functionality that is not required to listen for further instructions and/or parameters may be substantially disabled;
- disabling the high voltage output 552 unit and/or the high voltage part of the power supply 551;
- when using one or more antennas as the one or more energy receivers 500, detune the tuning circuit; and
- disconnecting one or more energy receivers 500 and interconnections 250 using suitable switches.
The skilled person will also realize that a plurality of high-energy modes and/or a plurality of lower-energy modes may be predetermined and made selectable using appropriate instructions. The stimulation device 100, 150 may be further configured to similarly switch between a high-energy and lower-energy modes substantially
simultaneously with the pulse energy controller 550 that it comprises.
The moments in time to switch between modes may be provided as appropriate conditions that the pulse energy controller 550 is configured to evaluate.
For example, by monitoring the electrical energy received at the one or more receivers 500 and/or at the interface, tl may be determined as the moment in time that a stimulation energy pulse 620 is detected that is longer than a predetermined time, such as 500 milliseconds. Additionally or alternatively, tl may be determined as the moment in time that the pulse received at the one or more receivers 500 exceeds a threshold voltage, such as 12 volts.
Similarly, t2 may be determined as the moment in time that no stimulation energy pulse 620 has been detected for a predetermined time, such as 2 seconds. Additionally or alternatively, t2 may be determined as the moment in time that the pulse received at the one or more receivers 500 drops below a threshold voltage, such as 2 volts. Additionally or alternatively, t2 may be determined as immediately after detection of three subsequent pulses at the one or more receivers 500. Additionally or alternatively, t2 may be determined as a fixed time after tl, such as 5 seconds.
In other words, the pulse energy controller 550 may be configured to switch between the high-energy and lower energy modes directly using instructions and/or parameters transmitted with the stimulation data 630, and/or using instructions and/or parameters derived from (indirectly and/or using them to define conditions) instructions and/or parameters transmitted with the stimulation data 630. All these cases are considered to be included when the pulse energy controller 550 switches between modes “as instructed”.
By suitable configuration of the stimulation energy transmitter 620, stimulation data transmitter and/or pulse energy controller 550, many more modes of operation may be provided. The configuration depicted in FIG. 8 is referred to here as configuration 1) to allow easier comparison. Three further non-limiting operating configurations are described below:
Configuration 2) On/off configuration with pulse parameter control: similar to configuration 1), the power supply 551 comprises a power source, such as a storage capacitor. The capacitor is sufficient to store charge for the entire stimulation period. The lower the stimulation frequency, the larger the size of the capacitor. The data communication and energy transmission signals are depicted
schematically in FIG. 4 A. A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
(feedback) 570 transmitted using, for example, a modulator 553a.. Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right. During a particular period of time, the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2. This is indicated as pulse [e].
The pulse energy controller 550 starts on the left-hand- side (time = 0) in lower- energy mode 550, as indicated by the pulse energy controller 550 waveform being 0.
In this example of a lower-energy mode 550, the logic control listens for stimulation data 630 being transmitted.
In this case, stimulation energy 620 is transmitted continuously over the whole time period depicted to charge the storage capacitor and to keep it charged. The pulse [a] is the first pulse to occur, and it starts on the left-hand side. As energy is transmitted 620 substantially continuously, the amplitude [a] of the stimulation energy may be substantially lower compared to a pulsed situation.
Stimulation energy is received continuously at the one or more receivers 500 over the same time period as for the stimulation energy 620. The pulse [b] starts on the left- hand side at the same moment. At least a portion of the electrical energy received is used to charge the storage capacitor comprised in the power supply 551.
The next pulse to occur is a pulse [c] of transmitted stimulation data 630 comprising one or more parameters and/or instructions. In this case, for example:
- a conditional instruction for the pulse energy controller 550 to switch from the lower-energy mode 550 to the high-energy mode 550 when a start pulse is detected in the simulation data 630;
- an instruction for the pulse energy controller 550 to switch from the high-energy mode 550 to the lower-energy mode 550 at a fixed time period after tl. In other words, the energy pulse controller 550 may calculate the moment in time t2;
- an instruction to enable transfer of electrical energy from the one or more receivers 500 to electrode number 2 (200 #2) during the high-energy mode 550;
- one or more parameters indicating an amplitude, a pulse width, an interval (or duty cycle) and a number of stimulation pulses to be provided. In this example, three equal pulses are to be provided to the electrode 200 #2.
- an instruction, that the number of pulses provided to the electrode #2 are counted, and just before the pulse energy controller 550 switches back into low energy mode 550, the data is to be transmitted back by the pulse energy controller 550.
After receiving the instructions and/or parameters 630, the pulse energy controller 550 configures itself appropriately:
- it enables electrical energy transfer from the one or more receivers 500 to electrode 200 #2;
- it enables switching from high-energy mode 550 to lower-energy mode 550 after generating a train of stimulation pulses;
- it enables the monitoring of the number of stimulation pulses; and
- it schedules transmission of the monitored data just before t2.
One or more of these configurations may be performed immediately. Alternatively or additionally, one or more of these configurations may be scheduled to be performed immediately upon the switching of the mode 550 to high-power mode 550.
-the next pulse depicted [d], is a transmittal on the stimulation data 630 channel indicating that stimulation should start (start signal [d]). The start signal [d] may be, for example, a pulse sent through the stimulation data 630 channel with a particular duration and/or amplitude. Or the next pulse sent through the stimulation data 630 channel within a particular time period. After detection of the start signal, the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [e]. - the logic control 553 controls the high voltage output 552 to generate three energy pulses with the predetermined amplitude, pulse width, and interval, and to transfer them as three stimulation pulses [f], [g], [h] to the electrode 200 #2.
-at the moment that the last of the three stimulation pulses [h] is passed to the electrodes 200, the monitored data is transmitted 570 as pulse [i], providing feedback data on the number of stimulation pulses provided to the electrode 200#2. This data 570 [i] may be received by the stimulation energy transmitter 620, and used to modify or maintain one or more of the transmitter parameters during the reconfiguration.
- at time t2, the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [e].
For configuration 2), advantageously, the data rate and communication overhead are relatively low, and the power efficiency is relatively high. The accurate timing of the high-energy mode 550 means that the length of time in the lower-energy mode 550 may be optimized. In addition, feedback data 570 may be sent at a convenient point during the operation
One of the insights on which the invention is based is that the data-rate may be kept relatively low without requiring a highly complex pulse energy controller - repetition of pulses (generating two or more pulses after switching from the lower-energy mode 550 to the high energy mode 550, and before any subsequent receipt of stimulation data (630)) is relatively straightforward to implement in the logic control 531. In addition, there is still a high degree of customization possible as important parameters determining characteristics of the pulse may still be modified between pulse sequences. Complex means anything found in a device which affects factors such as cost, lifetime, reliability and/or size - for example, the type and number of electrical components and integrated circuits, the type and number of antennas, the amount of programmable logic, the amount of memory storage, the presence of high-power components, etc. The level of complexity is affected, in general, by the functionality which is designed into the device - for example, the type and variation in the waveforms of the stimulation pulses to be provided, the degree of customization available, the number of different types of data/energy transmitters supported, etc.
By configuring and arranging the pulse energy controller 550 to generate two or more electrical stimulation pulses before any subsequent receipt of stimulation data 630, the pulse energy controller may operate more independently. This is particularly useful if data communication is interrupted, or even lost due to interference.
But disadvantages of configuration 2) include the pulse energy controller 550 requiring a relatively high degree of energy storage. For example, a buffer capacitor of up to 2 microFarad (uF) may be required. This increases the complexity and cost of the energy controller. In addition, large capacitors may not be possible in IC package sizes, increasing the volume of the pulse energy controller 550. The logic control 553 needs to be moderately complex to respond to different control parameters. It may also reduce the reliability and operating lifetime, and may provide a risk to the patient.
Although it may be convenient to have a relatively large separation between the energy pulse controller 550 and the stimulation electrodes 200, this requires longer interconnections 250 and longer leads. Due to their capacitive and/or inductive characteristics, longer interconnections 250 may result in unwanted energy storage in leads which may affect the energy efficiency of the energy pulse controller 550, and may also affect the characteristics of the generated stimulation pulses that reach the electrodes 200. By configuring the pulse energy controller 550 to connect and/or disconnect one or more electrodes 200, and providing a suitable instruction in the stimulation data 630, the effect of the long interconnections 250 may be reduced or even eliminated. The energy pulse generator 550 may, for example, comprise one or more electrode switches, comprised in the high voltage unit 552 under control of the logic control 553.
Additional problems may still occur with configuration 2) due to timing mismatches - for example, if the electrode switch is open too long, the power source may become exhausted prematurely due to the additional load.
Configuration 3) Pulsed energy transfer: similar to configuration 2), except that for this configuration, either no power source, or a greatly reduced power source, is required within the power supply 551.
In configuration 3), less charge is stored between providing the stimulation pulses to the electrodes 200. It is not necessary to store the levels of charge needed to generate a stimulation pulse because that electrical energy will be transmitted by the stimulation energy transmitter 620. But storage of a small amount is preferred to keep some logic functioning in this low-energy mode 550 - for example, one or more clock generator 553c configured as a mode timing clock. Typically, some logic must also be kept functioning to listen for signals using the stimulation data 630 channel. It may also be advantageous to maintain any memory storage, such as RAM, used to store instructions, parameters and/or characteristics to be used for subsequent pulses.
The data communication and energy transmission signals are depicted
schematically in FIG. 4B. A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
(feedback) 570 transmitted using, for example, a modulator 553a. Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right. During particular periods of time, the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2, and repeated twice. This is indicated as three pulses [c].
The pulse energy controller 550 starts on the left-hand- side (time = 0) in lower- energy mode 550, as indicated by the pulse energy controller 550 waveform being 0.
In this example of a lower-energy mode 550, the logic control listens for stimulation data 630 being transmitted.
The first pulse to occur is pulse [a], starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions for the subsequent pulse. In this case, for example:
- an instruction for the pulse energy controller 550 to switch from the lower- energy mode 550 to the high-energy mode 550 immediately - this pulse [a] in the stimulation data 630 channel is to be considered as a start pulse;
- an instruction for the pulse energy controller 550 to switch from the high-energy mode 550 to the lower-energy mode 550 at a fixed time period after tl for the next pulse. In other words, the energy pulse controller 550 may calculate the moment in time t2 for the next pulse;
- an instruction to enable transfer of electrical energy from the one or more receivers 500 to electrode number 2 (200 #2) during the high-energy mode 550;
- as in configuration 1), an instruction that while the pulse energy controller 550 is in high-energy mode 550, a pass-through functionality is to be used;
- one or more parameters indicating a pulse width and an amplitude. In this configuration, the interval between the pulses is to be determined by the appropriate start signal, pulse [a] on the stimulation data channel 630 and by the timing of the electrical energy received at the one or more receivers 500. In this configuration, the stimulation pulse is only provided to the electrode 200 #2 if the pulse energy controller 550 is in high-energy mode 550 (triggered by the start pulse [a]) when the energy pulse is received 500.
- an instruction, that actual pulse amplitude of each pulse provided to the electrode #2 is monitored, and just before the pulse energy controller 550 switches back into low energy mode 550, the data is to be transmitted back by the pulse energy controller 550.
After receiving the instructions and/or parameters 630, the pulse energy controller 550 switches the mode 550 to high-power and substantially simultaneously configures itself appropriately:
- it enables electrical energy transfer from the one or more receivers 500 to electrode 200 #2;
- it enables switching from high-energy mode 550 to lower-energy mode 550 between stimulation pulses;
- it enables the monitoring of the actual amplitude of stimulation pulses; and
- it schedules transmission of the monitored data just before t2 (after the next pulse).
After detection of this start signal [a], the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [b]
- substantially simultaneously with the switch to high-energy mode 550, a pulse [c] of stimulation energy 620 is transmitted.
- substantially simultaneously with the switch to high-energy mode 550, a corresponding pulse [d] is received at the one or more receivers 500. It comprises at least a portion of the electrical energy transmitted 620.
- a corresponding stimulation pulses [e] at approximately the same moment in time is provided (or generated) to electrode 200 #2. In this case, the pulse width and amplitude of each pulse [e] has been limited. Each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500
- after receiving the pulse [d] at the one or more receivers 500, the monitored data on the pulse width of that pulse 200 #2 is transmitted 570 as pulse [f
- at time t2, the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [b].
After detection of a second stimulation data transmission 630, interpreted as start signal [a], the pulse energy controller 550 switches from lower-energy mode 550 to high- energy mode 550, as indicated by the second transition from 0 to 1 of waveform [b], the pulse energy controller configures itself according to the instructions and/or parameters in the second stimulation data 630 transmission, and the cycle of pulses [c], [d], [e], [f] is repeated. Although depicted as having the same waveforms [e] at the electrode 200#2 and transmitting 570 the same waveform [f] of data, the skilled person will realize that in this configuration, the instructions and/or parameters may be changed per pulse, allowing a very high degree of customization. At time t2 (which may also be configured differently compared to the first pulse), the pulse energy controller 550 again switches from high- energy mode 550 to lower-energy mode 550, as indicated by the second transition from 1 to 0 of waveform [b]. After detection of a third stimulation data transmission 630, interpreted as start signal [a], the pulse energy controller 550 switches from lower-energy mode 550 to high- energy mode 550, as indicated by the third transition from 0 to 1 of waveform [b], the pulse energy controller configures itself according to the instructions and/or parameters in the third stimulation data 630 transmission, and the cycle of pulses [c], [d], [e], [f] is repeated. Although depicted as having the same waveforms [e] at the electrode 200#2 and transmitting 570 the same waveform [f] of data, the skilled person will realize that in this configuration, the instructions and/or parameters may be changed per pulse, allowing a very high degree of customization. At time t2 (which may also be configured differently compared to the first and second pulses), the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the third transition from 1 to 0 of waveform [b].
For configuration 3), advantageously, only a relatively low degree of energy storage is required to provide buffer capacitance. This may be available within an IC package. Use of a pass-through functionality in general may reduce the complexity of the hardware and/or software required to implement the pulse energy controller 550.
Alternatively, the instructions and/or parameters comprised in the stimulation data 630 may be further reduced, allowing a relatively simple logic control 553. Configuration 3) may also be modified such that the amplitude and pulse width of the stimulation pulses provided to the electrode 200 #2 are determined by the energy received, and the pulse duration, at the one or more receivers 500 and the pulse.
In general, simplification of the energy controller 550 may increase the reliability and operating lifetime. But disadvantages may include a relatively low power efficiency and relatively high data rates and communication overheads.
Additional problems may occur due to timing mismatches with configuration 3) - for example, if the stimulation energy 620 [d] is transmitted too early (before the pulse energy controller 550 has switched to high-energy mode 550 [c] and prepared itself to generate and provide the stimulation pulse [f ), then excess energy may need to be dissipated within the pulse energy controller 550.
Also, if the high-energy mode 550 is maintained too long, for example by keeping the electrode switch 552c for electrode 200 #2 open too long, any charge being retained to power the logic in the lower-energy mode 550 may become exhausted prematurely due to the additional load.
Configuration 4) Synchronized pulsed energy transfer: similar to configuration 3), except that for this configuration, parameters about the stimulation pattern are provided first, and not with each pulse. As with configuration 3), less charge needs to be stored between providing the stimulation pulses to the electrodes 200.
The data communication and energy transmission signals are depicted
schematically in FIG. 4C. A series of waveforms are depicted from top to bottom: the operating mode 550 of the pulse energy controller 550 (a 0 is lower-energy mode 550, a 1 is high-energy mode 550), stimulation energy transmitted 620, stimulation energy received 500, stimulation pulses provided to one or more electrode 200, and data
(feedback) 570 transmitted using, for example, a modulator 553a. Signals and/or pulses that are at the same horizontal position occur substantially simultaneously. Time runs from left to right. During particular periods of time, the pulse energy controller 550 is in high-energy mode 550 - this period is indicated by two vertical dotted lines, coinciding with the rise from 0 to 1 at tl and the fall from 1 to 0 of waveform 550 at t2, and repeated twice. This is indicated as three pulses [c].
The pulse energy controller 550 starts on the left-hand- side (time = 0) in lower- energy mode 550, as indicated by the pulse energy controller 550 waveform being 0.
In this example of a lower-energy mode 550, the logic control listens for stimulation data 630 being transmitted.
The first pulse to occur is pulse [a], starting on the left-hand side, is a transmittal of stimulation data 630 comprising one or more parameters and/or instructions. In this case, for example:
- a conditional instruction for the pulse energy controller 550 to switch from the lower-energy mode 550 to the high-energy mode 550 when a start pulse is detected in the simulation data 630
- an instruction for the pulse energy controller 550 to switch from the high-energy mode 550 to the lower-energy mode 550 at a fixed time period after tl. In other words, the energy pulse controller 550 may calculate the moment in time t2, and this is repeated for each pulse;
- an instruction to enable transfer of electrical energy from the one or more receivers 500 to electrode number 2 (200 #2) during the high-energy mode 550;
- as in configuration 1), an instruction that while the pulse energy controller 550 is in high-energy mode 550, a pass-through functionality is to be used;
- one or more parameters indicating a pulse width and an amplitude. In this configuration, the interval between the pulses is to be determined by the appropriate start signal, pulse [b] on the stimulation data channel 630 and by the timing of the electrical energy received at the one or more receivers 500. In this configuration, the stimulation pulse is only provided to the electrode 200 #2 if the pulse energy controller 550 is in high-energy mode 550 (triggered by the start pulse [b]) when the energy pulse is received 500.
- an instruction, that pulse width of each stimulation pulse provided to the electrode #2 is monitored, and just before the pulse energy controller 550 switches back into low energy mode 550, the data is to be transmitted back by the pulse energy controller 550.
After receiving the instructions and/or parameters 630, and/or upon switching the mode 550 to high-power, the pulse energy controller 550 configures itself appropriately:
- it enables electrical energy transfer from the one or more receivers 500 to electrode 200 #2;
- it enables switching from high-energy mode 550 to lower-energy mode 550 between stimulation pulses;
- it enables the monitoring of the width of stimulation pulses; and
- it schedules transmission of the monitored data just before t2 (after each pulse).
The next pulse depicted is a transmittal on the stimulation data 630 channel indicating that stimulation should start (start signal [b]). After detection of the start signal, the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the transition from 0 to 1 of waveform [c]. - substantially simultaneously with the switch to high-energy mode 550, a pulse [d] of stimulation energy 620 is transmitted.
- substantially simultaneously with the switch to high-energy mode 550, a corresponding pulse [e] is received at the one or more receivers 500. It comprises at least a portion of the electrical energy transmitted 620.
- a corresponding stimulation pulses [f at approximately the same moment in time is provided (or generated) to electrode 200 #2. In this case, the pulse width and amplitude of each pulse [f] has been limited. Each pulse at electrode 200 #2 comprises at least a portion of the electrical energy received at the one or more receivers 500
- after receiving the pulse [e] at the one or more receivers 500, the monitored data on the pulse width of that pulse 200 #2 is transmitted 570 as pulse [g]
- at time t2, the pulse energy controller 550 switches from high-energy mode 550 to lower-energy mode 550, as indicated by the transition from 1 to 0 of waveform [c].
After detection of a second start signal, pulse [b], the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the second transition from 0 to 1 of waveform [c], and the cycle of pulses [d], [e], [f], [g] is repeated. At time t2, the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the second transition from 1 to 0 of waveform [c].
After detection of a third start signal, pulse [b], the pulse energy controller 550 switches from lower-energy mode 550 to high-energy mode 550, as indicated by the third transition from 0 to 1 of waveform [c], and the cycle of pulses [d], [e], [f], [g] is repeated. At time t2, the pulse energy controller 550 again switches from high-energy mode 550 to lower-energy mode 550, as indicated by the third transition from 1 to 0 of waveform [c].
For configuration 4), advantageously, only a relatively low degree of energy storage is required to provide buffer capacitance. This may be available within an IC package. In addition, the device may operate with relatively low data rates and low communication overheads because there is only a need for a start signal [b] for the transmission/pass-through synchronization. The power efficiency may be higher than configuration 3) as the lower-energy mode 550 is used between pulses, and smaller wake- up times maximizes the time spent in the lower-energy mode 550 over an extended period of operation.
By providing a high degree of degree of transmission/high-energy mode 550 synchronization, the pulse energy controller 550 may be configured and arranged to switch to high-energy mode 550 substantially simultaneously, or immediately before, the receipt of stimulation energy 620 used to generate an electrical stimulation pulse. As no additional instructions and/or parameters 630 need to be read, no additional time must be reserved for interpreting the data and reconfiguring the pulse energy controller 550 before a pulse may be generated.
In general, by providing a high degree of independent control to a pulse energy controller 550, the need for data transfer during operation is reduced, allowing a lower data rate to be utilized. This may reduce the complexity of such a pulse energy controller 550. One of the insights upon which the invention is based is that a more efficient operation is possible if the need for an internal power source is greatly reduced, and the operation of the pulse energy controller 550 is synchronized to a high degree with the transfer of stimulation energy 620 (or the transfer of stimulation energy 620 is synchronized to a high degree with the operation of the pulse energy controller 550). This allows the data rate to be kept within practical levels.
For example, an estimation for as suitable data-packet size for configuration 4) may be:
- Handshake/ anti -colli si on 16x8=128 bits
- Unique Identification 40 bits - Stimulation parameters - Electrode number 16 bits
- Amplitude 5 bits (e.g. 32 values)
- Pulse width 5 bits (e.g. 32 values)
- period 5 bits (e.g. 32 values)
- Miscellaneous 8 bits
- CRC (Cyclic Redundancy Check) 16 bits
- Encryption 24 bits
Total 247 bits
Using a traditional on/off control, where a start instruction is followed by a stop instruction, the restrictions on pulse duration may mean that it is not possible to communicate a stop instruction before the desired end of a stimulation pulse. In such a case, the logic control 553 may be advantageously further configured to control pulse duration of the stimulation pulses.
Preferably, a permitted operating frequency, such as an ISM band, is used (in-band communication). The ISM radio bands are reserved internationally for industrial, scientific and medical (ISM) purposes other than telecommunications.
ISM frequencies include center frequencies 6.78 MHz, 13.56 MHz, 27.12 MHz, and 40.68 MHz providing bandwidths of 30 kHz, 14 kHz, 326 kHz, and 40 kHz, respectively.
To communicate 247 bit in less than 1 millisecond (msec) requires a data-rate of at least 240kbit/sec. Many existing protocols are not capable of providing sufficient bandwidth. Even those protocols that may theoretically support such a high data rate (for example, at high frequencies) often require ideal situations with large antennas, short ranges and ideal alignment. Interference and/or misalignment of transmitter 620 and receiver 500 may further reduce actual bandwidth. In addition, handshake overhead and protocol turn-around time between messages - 150 microseconds (usee) affect the practical data rate which may be achieved.
For example, in-band protocols:
- IS014443-A (13.56 MHz) 106kbit/s but larger overhead for handshake etc.
- ISO 14443 -B (13.56 MHz) 106kbit/s - IS015693 (13.56 MHz) 1.65 / 26.4kbit/s
- IS018000-3 (13.56 MHz) ~424kbit/s
ISO/IEC 14443 is an international standard that defines proximity (contactless) cards (types A & B) used for identification, and the transmission protocols for
communicating with them. The current version (14443-1 :2018, 14443-2:2016; 14443- 3:2018, 14443-4:2018) is available at www.iso.org. The nominal frequency is 13.56 MHz.
ISO/IEC 15693 is an international standard for vicinity cards (cards which can be read from a greater distance than proximity cards). The current version (15693-1 :2018, 15693-2:2019; 15693-3:2019) is available at www.iso.org. The nominal frequency is
13.56 MHz.
ISO/IEC 18000 is an international standard describing different RFID
technologies, each using different frequency ranges. The current versions (18000-3:2010) are available at www.iso.org. ISO 18000-3 is directed to air interface communications at
13.56 MHz.
For example, out-of-band protocols:
- Bluetooth LE (2.4 GHz) ~ 1 Mb/s but extra complexity in electronics
- Zigbee (2.4 GHz) 250 kbit/s
Zigbee is a communication protocol based on IEEE 802.15.4. The current version (802.15.4-2015) is available at standards.ieee.org.
By using a simple encoding for the patterns, the data rate may also be reduced - this is particularly advantageous when communicating at lower frequencies. For example, frequencies of 100 MHz or less. For example:
Pattern Electrodes Repetition
1 2 3 4 ... 11 12 R1 R2
A 0 1 0 0 . . . 0 0 1
B 1 1 1 0 . . . 0 0 1
C 0 0 0 0 . . . 1 1 0 1 Sequences may then be defined as, for example:
A param 20x
C param 3 Ox
etc
For configuration 4), the required data rate is very low - instructions and/or parameters are transmitted 630 when the stimulation energy 620 is not being transmitted, and the pulse energy controller 550 is not providing stimulation pulses. For example, one data transmission 630 per ten seconds, may be sufficient, resulting in a data rate of only a few bits per second.
The skilled person will also realize that the pulse energy controller 550 described herein is highly configurable. For example:
- between the transmission of stimulation energy pulses 620, a lower level of energy may be transmitted to sustain enough charge in the logic to operate reliably in the lower energy mode 550. This may also improve the responsiveness when the pulse energy controller 550 is switched to high-energy mode 550;
- feedback may be provided as transmitted pulses 570 relating to any aspect of the operation. They may be transmitted at particular times of the day. They may provide feedback about each stimulation pulse and/o feedback about a plurality of previous pulses;
- if a pulse energy controller 550 comprises one or more clock generators 553c, configurable as a stimulation pulse timing clock, configured and arranged to influence a temporal characteristic of the one or more electrical stimulation pulses provided to the one or more electrodes 200. For example, the stimulation pulse start time, the pulse width and/or the stimulation pulse end time. In other words, the pulse timing clock may be used to further improve the synchronization. By controlling the timing to a higher degree, the risk of timing mismatches with the received stimulation energy pulses at the one or more receivers 500 may be reduced. Optionally, the stimulation data 630 may comprise an instruction to set, reset, and/or synchronize one or more clock generators 553c;
- if the energy transmitter 620 and/or data transmitter 630 also comprise one or more clock generators, they may be further configured to allow these one or more clock generators to be synchronized with the pulse energy controller 550 - for example, when a first pulse of stimulation data 630 is transmitted or when a first pulse of stimulation energy 630 is transmitted. Optionally, the stimulation data 630 may comprise an instruction to synchronize a controller 550 clock generator to the data transmitter 630 and/or energy transmitter 620 clock generators;
- in configuration 3) and 4), stimulation pulses are only provided to the one or more electrode 200 if the pulse energy controller is in high-energy mode 550 when a stimulation energy pulse is received 500. This may also be advantageous if the pulse energy controller 550 is subjected to other external energy pulses, such as from
machinery, airport scanners, shop RFID detection ports or even a stimulation energy transmitter 620 from a different human or animal. By enforcing a handshake and/or encryption, the situations under which the pulse energy controller 550 is switched to high- energy mode 550 may be very precisely controlled. Alternatively or additionally, a switch to a lower-energy mode 550 may also be initiated under particular conditions and/or if electrical energy with undesired characteristics is detected.
In general, the device 100, 150 may be considered to have three main design restrictions:
- the distal end 100 may be substantially configured and arranged to be implanted proximate the tissue to be stimulated;
- the proximal end 150 may be substantially configured and arranged to receive 500 electrical energy; and
- one or more electrical connections between the proximal end 150 and the distal end 100.
Depending on the type of stimulation and the implantation positions on the human or animal body, the device 100, 150 may be optimized to comply with one of the design restrictions, or comprises may be made based on two or more design restrictions. For example, when stimulating nerves on the forehead, a longer substrate 300 (longer lead) may be used such that the proximal end 150 and the receiver 500 of electrical energy may be disposed close to an ear or at the back of the head. The skilled person will also realize that the one or more stimulation electrodes 200 may be provided proximate the pulse energy controller 550.
FIG. 5 and FIG. 6 depict examples of nerves that may be stimulated using a suitably configured devices 100, 150 with an implantable distal end 100. It may provide neurostimulation to treat, for example, headaches or primary headaches.
FIG. 5 depicts the left supraorbital nerve 910 and right supraorbital nerve 920 which may be electrically stimulated using a suitably configured device. Figure 6 depicts the left greater occipital nerve 930 and right greater occipital nerve 940 which may also be electrically stimulated using a suitably configured device.
Depending on the size of the region to be stimulated and the dimensions of the part of the device to be implanted, a suitable location is determined to provide the electrical stimulation required for the treatment. Approximate implant locations for the distal part of the stimulation device comprising stimulation devices 100, 150 are depicted as regions:
- location 810 for left supraorbital stimulation and location 820 for right supraorbital stimulation for treating chronic headache such as migraine and cluster.
- location 830 for left occipital stimulation and location 840 for right occipital stimulation for treating chronic headache such as migraine, cluster, and occipital neuralgia.
In many cases, these will be the approximate locations 810, 820, 830, 840 for the implantable part of the device 100, 150.
For each implant location, 810, 820, 830, 840 a separate stimulation system may be used. Where implant locations 810, 820, 830, 840 are close together, or even overlapping, a single stimulation system may be configured to stimulate at more than one implant location 810, 820, 830, 840.
A plurality of stimulation devices 100, 150 may be operated separately, simultaneously, sequentially or any combination thereof to provide the required treatment.
FIG 7 depict further examples of nerves that may be stimulated using a suitably configured improved stimulation device 100, 150 to provide neurostimulation to treat other conditions. As in FIG. 5 and 6, the ability to increase the stimulation current density in transverse directions 720 improves the stimulation along a longitudinal axis of the nerve or nerve branches. The locations depicted in FIG. 5 and FIG. 6 (810, 820, 830, 840) are also depicted in FIG. 7.
Depending on the size of the region to be stimulated and the dimensions of the part of the device to be implanted, a suitable location is determined to provide the electrical stimulation required for the treatment. Approximate implant locations for the part of the stimulation device comprising stimulation electrodes are depicted as regions:
- location 810 for cortical stimulation for treating epilepsy;
- location 850 for deep brain stimulation for tremor control treatment in Parkinson’s disease patients; treating dystonia, obesity, essential tremor, depression, epilepsy, obsessive compulsive disorder, Alzheimer’s, anxiety, bulimia, tinnitus, traumatic brain injury, Tourette’s, sleep disorders, autism, bipolar; and stroke recovery
- location 860 for vagus nerve stimulation for treating epilepsy, depression, anxiety, bulimia, obesity, tinnitus, obsessive compulsive disorder and heart failure;
- location 860 for carotid artery or carotid sinus stimulation for treating hypertension;
- location 860 for hypoglossal & phrenic nerve stimulation for treating sleep apnea;
- location 865 for cerebral spinal cord stimulation for treating chronic neck pain;
- location 870 for peripheral nerve stimulation for treating limb pain, migraines, extremity pain;
- location 875 for spinal cord stimulation for treating chronic lower back pain, angina, asthma, pain in general;
- location 880 for gastric stimulation for treatment of obesity, bulimia, interstitial cystitis;
- location 885 for sacral & pudendal nerve stimulation for treatment of interstitial cystitis;
- location 885 for sacral nerve stimulation for treatment of urinary incontinence, fecal incontinence;
- location 890 for sacral neuromodulation for bladder control treatment; and - location 895 for fibular nerve stimulation for treating gait or footdrop.
Other condition that may be treated include gastro-esophageal reflux disease and inflammatory diseases.
The descriptions thereof herein should not be understood to prescribe a fixed order of performing the method steps described therein. Rather the method steps may be performed in any order that is practicable. Similarly, the examples are used to explain the algorithm, and are not intended to represent the only implementations of these algorithms - the person skilled in the art will be able to conceive many different ways to achieve the same functionality as provided by the embodiments described herein.
In general, for any of the configurations described and depicted in this disclosure, any electrode 200, 400, 450 may be connected as either a stimulating 200 or return electrode 400, 450. This may be advantageous if it is uncertain whether the implantable distal end is above or below the targeted tissue - for example, above or below a nerve. This may be advantageous if it is uncertain whether the implantable distal end is above or below the targeted tissue - for example, above or below a nerve.
Although the present invention has been described in connection with specific exemplary embodiments, it should be understood that various changes, substitutions, and alterations apparent to those skilled in the art can be made to the disclosed embodiments without departing from the spirit and scope of the invention as set forth in the appended claims.
REFERENCE NUMBERS USED IN DRAWINGS
100 first embodiment of a proximal end of a stimulation device
150 first embodiment of an implantable distal end of a stimulation device
200 one or more stimulation electrodes
250 one or more electrical interconnections
300 an elongated substrate
310 a first substantially planar transverse surface 320 a second substantially planar transverse surface
400 one or more distal return electrode
450 one or more proximal return electrode
500 one or more energy receivers
500a one or more tuning components
550 pulse energy controller, energy mode of pulse energy controller (high or lower)
551 controller - power supply
551a rectifier
551b one or more high voltage buffers
551c high voltage monitor
55 Id low voltage regulator
551e one or more low voltage buffers
552 controller - high voltage output
552a current source
552b one or more current monitors
552c one or more electrode switches
553 controller - logic control
553a modulator
553b demodulator
553c one or more clock generators
553d one or more controllers
570 controller data transmitter, controller data
620 stimulation energy transmitter, stimulation energy
630 stimulation data transmitter, stimulation data
700 a longitudinal axis
720 a first transverse axis
750 a second transverse axis
810 location for left supraorbital nerve or cortical stimulation
820 location for right supraorbital stimulation
830 location for left occipital nerve stimulation
840 location for right occipital nerve stimulation
850 location for deep brain stimulation 860 location for vagus nerve, carotid artery, carotid sinus, phrenic nerve or hypoglossal stimulation
865 location for cerebral spinal cord stimulation
870 location for peripheral nerve stimulation
875 location for spinal cord stimulation
880 location for gastric stimulation
885 location for sacral & pudendal nerve stimulation
890 location for sacral neuromodulation
895 location for fibular nerve stimulation
910 left supraorbital nerve
920 right supraorbital nerve
930 left greater occipital nerve
940 right greater occipital nerve

Claims

CLAIMS:
1. A method of controlling pulse energy of a tissue stimulation device (100, 150), the tissue stimulation device (100, 150) comprising:
- one or more energy receivers (500), configured and arranged to wirelessly receive a pulse train of energy from an associated stimulation energy transmitter (620) when the associated stimulation energy transmitter (620) is proximate; and
- one or more stimulation electrodes (200);
- a pulse energy controller (550), configured and arranged to receive electrical energy from the one or more energy receivers (500) and to transfer electrical energy as one or more electrical stimulation pulses to the one or more stimulation electrodes (200); the method comprising:
- configuring and arranging the pulse energy controller (550) to operate in a high- energy mode (550), wherein electrical energy is transferrable; and in a lower-energy mode (550), wherein the transfer of electrical energy to one or more stimulation electrodes (200) is restricted;
- configuring and arranging the stimulation device (100, 150) to detect when first predetermined conditions have been detected whereby the pulse energy controller (550) is switched from the lower-energy mode (550) to the high-energy mode (550) substantially simultaneously, or immediately before, the receipt of electrical energy, suitable for providing an electrical stimulation pulse, from the one or more energy receivers (500);
- configuring and arranging the stimulation device (100, 150) to detect when second predetermined conditions have been detected whereby the pulse energy controller (550) is switched from the high-energy mode (550) to the lower-energy mode (550) between individual pulses of the pulse train of energy received (500).
2. The method according to claim 1, wherein the method further comprises configuring and arranging the tissue stimulation device (100, 150):
- to monitor electrical energy received from the associated stimulation energy transmitter (620); and
- to derive the first and/or second predetermined conditions from the monitored electrical energy.
3. The method according to claim 2, wherein the method comprises configuring and arranging the tissue stimulation device (100, 150) to monitor electrical energy received at the one or more energy receivers (500).
4. The method according to any preceding claim, wherein the one or more pulses received at the one or more energy receivers (500) have a pulse width in the range 100 microsecond to 1 millisecond.
5. The method according to any preceding claim, wherein the one or more pulses received at the one or more energy receivers (500) are repeated with a frequency in the range 40 to 1000 Hz.
6. The method according to any preceding claim, wherein the tissue stimulation device (100, 150) further comprises a data receiver (553), configured and arranged to wirelessly receive, from the one or more energy receivers (500), stimulation data (630); the method further comprising:
- configuring the tissue stimulation device (100, 150) to derive the first and/or second predetermined conditions from an instruction comprised in the stimulation data (630); and/or
- configuring the tissue stimulation device (100, 150) to predetermine one or more corresponding characteristics of one or more subsequent electrical stimulation pulses from the stimulation data.
7. The method according to any preceding claim, the method comprising:
- configuring and arranging the pulse energy controller (550) to provide two or more electrical stimulation pulses after switching from the lower-energy mode (550) to the high energy mode (550), and before any subsequent receipt of stimulation data (630).
8. The method according to any preceding claim, wherein the pulse energy controller (550) further comprises one or more electrode switches, the method further comprising:
- configuring and arranging the electrode switches to restrict the transfer of electrical energy to one or more stimulation electrodes (200) when the pulse energy controller (550) is operating in the lower-energy mode (550).
9. The method according to claim 8, wherein stimulation data (630) comprises an instruction to connect and/or disconnect one or more stimulation electrodes (200), the method further comprising:
- configuring and arranging the pulse energy controller (550) to connect and/or disconnect the energy through one or more electrical connections (250) to one or more stimulation electrodes (200) as instructed.
10. The method according to any preceding claim, wherein the pulse energy controller (550) further comprises a pulse timing clock, the method further comprising:
- configuring and arranging the pulse timing clock to influence a temporal characteristic of the one or more electrical stimulation pulses provided by the pulse energy controller (550).
11. The method according to any preceding claim, wherein the pulse energy controller (550) further comprises a mode timing clock, the method comprising:
- configuring and arranging the mode timing clock to switch from the high-energy mode (550) to the lower-energy mode (550) and/or from the lower-energy mode (550) to the high-energy mode (550).
12. The method according to any preceding claim, wherein the energy transmitter (620) further comprises an energy timing clock the method further comprising:
- configuring and arranging the energy timing clock to influence a temporal characteristic of the stimulation energy (620); the stimulation data (630) comprising an instruction to synchronize one or more timing clocks, and
- configuring and arranging the pulse energy controller (550) to synchronize the energy timing clock to a pulse timing clock and/or mode timing clock.
13. The method according to any preceding claim, wherein the one or more corresponding characteristic of one or more subsequent electrical stimulation pulses is selected from the group consisting of:
- a pulse amplitude, a pulse width, a period, a duty cycle, a switch from higher- energy mode (550) to low-energy mode (550), a switch from low energy mode (550) to higher-energy mode (550), a number of pulses to be provided, a number of pulses to be repeated, a duration of pulses, a start time, an end time, a selection of one or more electrodes, a selection of one or more electrodes as a return electrode, a timing clock synchronization, a timing clock set, a timing clock reset, handshake data, anti-collision data, encryption data, identification data, error detection data, CRC data, and any combination thereof.
14. The method according to any preceding claim, wherein the one or more energy receivers (500) comprise a coil with one or more windings.
15. The method according to any preceding claim, wherein the tissue stimulation device (100, 150) further comprises:
- a return electrode (450), proximate the energy pulse controller (550), configured to provide, in use, a corresponding electrical return for one or more stimulation electrodes (200).
16. The method according to any preceding claim , wherein the one or more stimulation electrodes (200) are comprised in an elongated substrate (300), disposed along a longitudinal axis (700).
17. The method according to claim 16, wherein the tissue stimulation device further comprises:
- a return electrode (400), proximate the one or more stimulation electrodes (200), configured to provide, in use, a corresponding electrical return for one or more stimulation electrodes (200).
18. The method according to any preceding claim, wherein the stimulation energy transmitter (620) further comprises a stimulation data transmitter (630), the method further comprising:
- configuring and arranging the stimulation data transmitter (630) to provide instructions to the tissue stimulation device (100, 150) as stimulation data (630).
19. The method according to any preceding claim, wherein the method further comprises configuring and arranging the tissue stimulation device (100, 150) for stimulating:
- one or more nerves, one or more muscles, one or more organs, spinal cord tissue, and any combination thereof.
20. The method according to any preceding claim, wherein the method further comprises configuring and arranging the tissue stimulation device (100, 150) for treatment of:
- headaches, primary headaches, incontinence, occipital neuralgia, sleep apnea, hypertension, gastro-esophageal reflux disease, an inflammatory disease, limb pain, leg pain, back pain, lower back pain, phantom pain, chronic pain, epilepsy, an overactive bladder, poststroke pain, obesity, and any combination thereof.
PCT/IB2020/054362 2019-05-09 2020-05-08 An electrical stimulation device with synchronized pulsed energy transfer WO2020225780A1 (en)

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