RU2286182C2 - Multi-channel programmed electric neurostimulator - Google Patents

Abstract

FIELD: medical facilities.

SUBSTANCE: device can be used for stimulating human nervous system by electric current. Device allows influencing onto central and peripheral nervous system by method of remote long-term stimulation by using implanted electrodes. Electric neurostimulator has non-implanted part in form of pulse-width modulation pulse transmitter unit and implanted part in form of receiving unit. Units are made for magnetic-induction coupling between each other. Pulse transmitter has re-tunable high-frequency oscillator, telemetry channel receiver, control programmed microcontroller of transmitter, control and program keyboard, liquid crystal alphabet-digital monitor and power unit. Transmitter is connected with companion aerial for transmitting high-frequency energy and for receiving telemetry data. Receiver unit has aerial for receiving high-frequency energy and for transmitting telemetry data. It also has control programmed microcontroller of receiving unit, digital-to-analog converter, amplifier, multi-channel switch, electrodes and connectors for connecting electrodes with multi-channel switch. Multi-channel switch has its working inputs and outputs, which form contacts of receiving unit, is connected with electrodes via connectors to form stimulation channels which can be put into operation together in groups or separately or all together. Device can be used for electric stimulation of different areas of brain and for epidural stimulation of spinal cord. Diseases as Parkinsonism, infantile cerebral paralysis, torsion dystonia, and spastic reactions, some forms of epilepsy and consequences of heavy cranial-brain traumas can be treated.

EFFECT: widened functional capabilities.

14 cl, 12 dwg

Description

The invention relates to medical equipment, in particular to devices for electrotherapy, designed to stimulate the nervous system with alternating current.

A multi-channel programmable electrical neurostimulator is designed to affect the central and peripheral nervous system through long-term remote stimulation using implantable electrodes. The device can be used to treat a number of neurological diseases, in particular: parkinsonism, cerebral palsy, torsion dystonia, spasticity, some forms of epilepsy, the consequences of severe traumatic brain injuries and psychopathological syndromes, by electrical stimulation of various areas of the brain and epidural spinal cord stimulation.

The most famous electrical neurostimulators of a similar purpose are devices of the company Medtronic Inc (USA).

Thus, in patent US 6505077 B1, an electroneurostimulator is disclosed, the implantable part of which contains a processor, a memory unit, a power source, a loop antenna for recharging the power source from the outside, and other elements for receiving stimulation signals of the desired type. During the recharge of the power source, it is possible to reprogram the electrical neurostimulator using an external programmer and monitor the relative position of the antennas. In this case, the antenna for recharging can perform the function of an antenna for telemetry.

However, the known electrical neurostimulator is not multi-channel and does not have separate control modes for the doctor and patient.

The prototype of the claimed electroneurostimulator is a device disclosed in US 5941906 A and containing: a control unit, a memory unit, a power supply unit with an antenna for recharging and a telemetry unit. The electroneurostimulator has many mutually isolated stimulation channels programmed using an external programmer.

However, this electroneurostimulator also does not have separate control modes for the doctor and patient, and is too complex for widespread use.

The objective of the claimed invention is the creation of an electrical neurostimulator with improved technical and operational characteristics.

The technical result of the invention is to expand the functionality of the electroneurostimulator due to the implementation of operating modes that provide separate control for the doctor and patient, as well as ensuring complete mutual independence of the stimulation channels. In addition, the therapeutic effect of the use of an electron neurostimulator is increased due to the choice of the working ranges of stimulation signals taking into account modern requirements and the control of the level of energy transmitted to the implanted part due to constant monitoring of the relative position of the transmitter and receiver antennas.

The technical result is achieved by the fact that the electroneurostimulator includes a non-implantable part in the form of a pulse transmitter block with pulse-width modulation, an implantable part in the form of a receiver block, made with the possibility of magnetic induction coupling. Moreover, the pulse transmitter is connected to a remote antenna for transmitting energy in the form of a high-frequency electromagnetic field and receiving telemetric information and contains a tunable high-frequency generator, a telemetry channel receiver, a reference frequency generator of the telemetry channel receiver, a programmable transmitter microcontroller, a control and programming keyboard, and an alphanumeric LCD. display, power supply, power management unit. The receiver unit, in turn, contains an antenna for receiving energy in the form of a high-frequency electromagnetic field and transmitting telemetric information, a programmable receiver microcontroller, a digital-to-analog converter, a power amplifier, a multi-channel switch, electrodes and connectors for connecting electrodes to a multi-channel switch, a current measuring device, a signal conditioner telemetry and a reference frequency generator of the telemetry signal generator. At the same time, the programmable control microcontroller of the transmitter is connected by its outputs to a reconfigurable high-frequency generator and a liquid crystal alphanumeric display, its inputs to a telemetry channel receiver, a control and programming keyboard and a power supply unit connected to a power control unit configured to connect to a charger, the output the high-frequency generator is connected to a remote antenna, to which the input of the telemetry channel receiver is also connected, the first input One of the control programmable microcontroller of the receiver is connected to the antenna of the receiver unit, the first output of the control programmable microcontroller of the receiver is connected to the multichannel switch via series-connected digital-to-analog converter and power amplifier, the multichannel switch is connected by its working inputs and outputs forming the contacts of the receiver block to the electrodes through the connectors, forming stimulation channels, included individually or by any groups, or all at the same time but, the programmable microcontroller control receiver associated with a multichannel switch and through its second and third inputs are inputs of telemetry, respectively, via a current measuring device directly, and with antenna receiver unit via a telemetric output and coupled thereto shaper telemetry signals.

The listed set of essential features is sufficient to achieve a technical result in all cases to which the requested amount of legal protection applies.

In special cases of its implementation or use, the control microcontrollers of the transmitter and receiver contain software that implements the function of separate control modes of the electroneurostimulator for the doctor and patient.

The stimulator channels contain a limiter that prevents the coincidence of their current stimulating pulses in time.

The electrodes of the neurostimulator may be bipolar, quadropolar or multipolar.

The electroneurostimulator can be configured to generate a sequence of biphasic stimulating pulses of any polarity on any pairs of contacts of the receiver unit.

In this case, the electroneurostimulator can be made with the possibility of discrete control of the voltage amplitude of the main part of biphasic pulses from -5.0 to +5.0 V in 0.1 V increments in any channel of the device. The full voltage amplitude of biphasic pulses in any channel of the device does not exceed 12 V. The frequency of biphasic pulses is from 1 to 250 Hz, while the frequency can be discretely controlled in the range from 1 to 15 Hz in increments of 1 Hz, in the range from 15 to 100 Hz - with a step of 5 Hz, and in the range from 100 to 250 Hz - with a step of 10 Hz, when one or more channels are switched on at any pairs of contacts of the receiver unit. The duration of the main part of biphasic pulses is discretely controlled from 50 to 750 μs in increments of 50 μs, when one or more channels are switched on on any pairs of contacts of the receiver unit. The duration of the interval between the main and relaxation part of each biphasic pulse is not more than 100 μs, at any frequency in any channel of the device.

The electroneurostimulator can be configured to generate a sequence of biphase packs of stimulating pulses of any polarity on any pairs of contacts of the receiver unit.

In this case, the electroneurostimulator can be made with the possibility of discrete control of the voltage amplitude of the main and relaxation parts of the biphasic pulse train from -5.0 to +5.0 V in 0.1 V increments in any channel of the device, when one or more channels of the device are turned on . The follow-up period for biphasic bursts of pulses is regulated from 1 to 255 s, when one or more channels are switched on at any pair of contacts of the receiver unit, and the follow-up period is discretely controlled in increments of 1 s in any channel of the device. The duration of the main part of the biphasic pulse train is discretely controlled from 1 to 255 s with an interval of 1 s in any channel of the device. The rise time of the amplitude of the biphasic pulse train is discretely controlled from 0 to 15 s, with an interval of 1 s, in any channel of the device. The rate of increase in the amplitude of the biphasic pulse train is adjustable from 100 to 1500 mV / s, in increments of 100 mV / s, in any channel of the device. In this case, the total maximum voltage amplitude of the biphasic pulse packets does not exceed 12 V.

The invention is illustrated by figures, which show:

- structural diagram of an electrical neurostimulator (figure 1);

- a sequence of biphasic pulses (figure 2);

- a sequence of biphasic bursts of pulses (figure 3);

- General view of the transmitter and the attached antenna (figure 4);

- a general view of the receiver with attachable connectors and electrodes (figure 5);

- General view of the electrodes (Fig.6);

- electrical circuit diagram of the first transmitter board (Fig.7);

- a circuit diagram of a second transmitter board (Fig. 8);

- circuit diagram of the receiver (Fig.9);

- scheme of the algorithm of the first mode of operation (figure 10);

- scheme of the algorithm of the second mode of operation (11);

- scheme of the algorithm of the third mode of operation (Fig).

The claimed electrical neurostimulator consists of a non-implantable part, an implantable part and a charger. The non-implantable part comprises a transmitter 1 and an antenna of the transmitter 18, which is a remote antenna. The implantable part of the device contains a receiver 2, as well as connectors and electrodes.

The transmitter 1 contains a tunable high-frequency generator 19, a telemetry channel receiver 17 connected to a reference frequency generator 16, a control and programming keyboard 13, an LCD alphanumeric display 15, a power supply 12 connected to the charger through a power control unit 11 and providing electrical energy to all transmitter elements that need it. The control programmable microcontroller 14 (PIC16F87x) is connected by one of its outputs to a high-frequency generator 19, and one of its inputs to the output of a telemetry channel receiver 17. The transmitter 1 is connected to a remote antenna 18 for transmitting high-frequency energy and receiving telemetry information, respectively, through the output of a high-frequency generator 19 and the input of the receiver of the telemetry channel 17.

The high-frequency generator 19 is a push-pull high-frequency generator with external excitation and a transformer output. It consists of: a bass reflex, built using a chip 74НS74 (INTERNATIONAL RECTIFIER) buffer cascade on IR4426 (INTERNATIONAL RECTIFIER); and an output stage on two transistors IRLML2402 (INTERNATIONAL RECTIFIER).

The transmitter battery voltage converter is implemented on the MAX668 chip (MAXIM SEMICONDUCTOR), and the + 5V regulator is implemented on the LP2951 chip (NATIONAL SEMICONDUCTOR).

The transmitter is made in the form of a rectangular box consisting of a housing and a cover (figure 4). The box material is acrylonitrile butadiene styrene (ABS) and polystyrene. On the front panel of the transmitter there is a liquid crystal display, a control and programming keyboard. The transmitter has connectors for charging the battery and for connecting a remote antenna.

The transmitter’s remote antenna is a disk consisting of a flat inductor wound with a copper wire in a spiral of Archimedes, which is filled with silicone rubber. The remote antenna is connected to the transmitter by means of an electric cable mounted in the antenna, at the end of which there is a cable connector. The remote antenna has dimensions of 90 × 660 × 5 mm.

The receiver 2 contains a series-connected antenna for receiving high-frequency energy and transmitting telemetric information 23, a programmable microcontroller 21 (PIC16F87x), a digital-to-analog converter 25, a power amplifier 26, a multi-channel switch 28 (made on analog keys ADG452 from ANALOG DEVICES). In addition, the receiver includes a current measuring device 27 and a telemetry signal generator 22 connected to a reference frequency generator 24. The electrodes are connected to the multi-channel switch through connectors.

The receiver (figure 5) is a receiving antenna of copper wire wound on a frame. Inside the frame is an electric capacitor, a microcontroller and a number of auxiliary electronic devices. The electric capacitor together with the receiving antenna is an oscillatory circuit tuned to a frequency of 2 MHz. The carcass is drenched with epoxy resin cured with diethylene triamine.

Electrodes are electrical conductors designed to transmit stimulating pulses to the patient's brain. The electrodes can vary in length, the number of pairs of contacts "input-output", the distance between the output contacts and the configuration of the output contacts. The electrode shell is made of polyethylene.

The connectors are two-sided connectors of various lengths, differing both in the number of pairs of input-output contacts and in the configuration of the outputs, which determines the number of connected electrodes. The input and output contacts of the connectors are connected by a wire harness. Each harness has a polyethylene coating with a thickness of 0.035 mm. The outer shell of the connectors is made of silicone rubber.

With the simultaneous supply of stimulating pulses to the contacts of different channels, due to the coincidence in time of the pulses in antiphase, the total potential difference can exceed the set value between the contacts of the electrodes implanted in the patient’s brain. To eliminate the undesirable effect in all channels, a software-implemented limiter is provided that delays the generation of the current pulse in these channels at the time of the coincidence effect.

The operation of the device should be considered in the interaction of the included circuit "transmitter - remote antenna - receiver - connector - electrode". The transmitter 1, after switching on, starts to generate control pulses, the shape of which depends on the program entered into the microcontroller 14. In this case, the microcontroller 14 starts the high-frequency generator 19, which generates a code signal to verify the correct positioning of the transmitting 18 and receiving 23 antennas. Service feedback pulses make it possible to detect the absence of stimulation in case of disconnection or incorrect orientation of the remote antenna 18 and receiver 2. To transmit telemetry signals from the receiver to the transmitter, the Q-switching method of the transmitting antenna was implemented by shunting the receiving antenna. Shunting is performed by the formation of telemetry signals of the receiver.

With the correct location of the antennas, the control pulses arrive at the remote antenna 18, through which the stimulation commands (parameters) are transmitted from the transmitter 1 to receiver 2. The implanted subcutaneous receiver 2 should be aligned with the remote antenna at a distance from the receiver from the antenna from 5 to 15 mm. The method of signal transmission from the external antenna to the antenna of the implanted receiver is magnetic induction in the radio frequency range of 2 MHz. The control pulses are simultaneously energy pump pulses that replace the receiver with a power source. The receiver, in turn, generates stimulating impulses that enter the patient’s brain through the connector and electrode.

Through the receiving antenna 23, the pulses are fed to the control microcontroller 21 of the receiver 2, after which they are digital-to-analogue converted (block 25) and the power is amplified (block 26) before being fed to the multi-channel switch 28, the operation of which is determined by the controlling microcontroller 21.

At the same time, voltage and current are measured (block 27) on the electrodes. These data are constantly used by the receiver unit to ensure the stability of the amplitude of the stimulating pulses, and at the request of the transmitter, telemetry signals are generated in block 22, which subsequently enter the receiver of the telemetry channel 17 of transmitter 1.

Through the software part of the control microcontrollers 14 and 21, as well as the multi-channel switch 28, the device implements several (for example, one, two or four) independent channels for generating biphasic pulses or biphasic pulse packets. Biphase pulses and biphasic pulse packets in the channels can differ in the amplitude of the voltage of the main (frontal) and relaxation part of the pulse or packet of pulses in the repetition rate and duration of the main and relaxation part of the biphasic pulse and differ in the repetition period and duration of the main and relaxation part of the biphasic pulse packet. Channels can be assigned to receiver contacts in any combination and any selected polarity sign on these contacts.

The polarity between the contacts within the same channel is programmed by a neurosurgeon taking into account the stereometric arrangement of the contacts of the implanted electrodes in the patient’s brain tissue.

Stimulation channels can be switched on individually, in any combination, or all at the same time.

The transmitter can operate in three modes, which is provided by the software of the control microcontrollers of the transmitter and receiver.

First mode. The first regimen is available to both the attending physician and the patient. This mode is designed to independently achieve the patient the greatest comfort of stimulation by limited amplitude adjustment. This mode is the mode of active operation of the transmitter. In this mode, the voltage amplitude of the main part of the sequence of biphasic pulses or bursts of pulses can be adjusted by the patient within ± 1 V of the value set by the neurosurgeon, but within the range of ± 5 V. The amplitude value set by the patient is not remembered when the transmitter is turned off. If the transmitter does not receive feedback from the receiver, that is, if the distance between the receiver and the remote antenna is too large or the antennas are not aligned, then the transmitter begins to emit frequent sound signals. In this case, the patient must press the remote antenna connected to the transmitter to the implantation site of the receiver. In the absence of feedback, the transmitter should turn off automatically after 2 minutes of searching for communication with the receiver.

Second mode. When you enter the access code, the transmitter enters the passive operation mode. In this mode, the transmitter is tuned by a neurosurgeon without patient intervention. The second mode is a mode for programming the parameters of stimulating pulses or bursts of pulses. This mode is introduced from the state of the first mode by entering an access code. After setting all the parameters, their value is stored and locked. From this mode, there is a transition to the beginning of the second mode to check the correct settings, or a transition to the first mode. The functioning of the channel or their combination is automatically activated if, after setting the channel number on the display, the necessary settings for the amplitude, frequency and duration of biphasic pulses or similar parameters for biphasic pulse packets are made.

If you need to use only one channel, then you should "reset" the duration of biphasic pulses and biphasic bursts of all channels except for the planned channel.

The transmitter turns off automatically after 2 minutes after the last press of any button.

The third mode. The mode is intended for the correction of settings in the postoperative period. The third mode is a mode of reprogramming parameters according to updated data after implantation of the receiver and electrodes, and is also intended to determine the actual value of voltage and current in one or another channel. After setting or changing the parameters, it is possible to return to the beginning of the third mode to check the correctness of the settings, or go to the first mode. This mode can be entered from any state of the second mode by re-entering the same access code. This code should not be known to the patient in order to avoid the occurrence of traumatic effects.

When you re-enter the code from any position of the second transmitter operating mode, the transmitter switches to the active transmitter tuning mode. In this mode, the transmitter can be tuned by a neurosurgeon both in the absence and in the presence of feedback “transmitter-antenna-receiver”. If there is feedback, the neurosurgeon should lean the remote antenna against the implantation site of the receiver. The antenna and the implanted receiver should be located approximately on the same axis. The audible feedback signals should stop. Switching channels on and off is the same as in the second mode.

The transmitter turns off automatically after 2 minutes if there is no feedback from the receiver.

When you turn on channels with a number higher than the first, while working with the first, you should bear in mind the fact that the first channel is a priority regardless of the contact numbers programmed for it. The second channel takes precedence over the third, and the third - over the fourth. This is expressed in the fact that when the turn-on time of the channels coincides, the low-order channel is turned on, and the inclusion of the high-order channel is shifted by the time necessary to complete the pulse life in the low-order channel.

All of the above remains true for the case of generation of biphasic pulse packets, since biphasic packets are filled with the same biphasic pulses.

Stimulation modes and intervals between sessions are determined by the attending neurosurgeon.

Claims (14)

1. Electrostimulator, which includes a non-implantable part in the form of a pulse transmitter block with pulse-width modulation, an implantable part in the form of a receiver block, configured to magnetically induce communication with each other, and the pulse transmitter is connected to a remote antenna for transmitting energy in the form of a high-frequency electromagnetic field and receiving telemetric information and contains a highly configurable high-quality generator, a telemetry channel receiver, a reference frequency generator, a receiver and a telemetry channel controlling a programmable microcontroller of a transmitter, a control and programming keyboard, a liquid crystal alphanumeric display, a power supply unit and a power control unit, a receiver unit contains an antenna for receiving energy in the form of a high-frequency electromagnetic field and transmitting telemetry information, a programmable control microcontroller for the receiver, digital-analog converter, power amplifier, multi-channel switch, electrodes and connectors for connecting electrodes mono-channel switch, current measuring device, telemetry signal generator and reference frequency generator of the telemetry signal generator, while the control programmable microcontroller of the transmitter is connected by its outputs to a configurable high-frequency generator and a liquid crystal alphanumeric display, its inputs with a telemetry channel receiver, a programming keyboard and a power unit connected to a power control unit configured to connect to a charger, the output of the high-frequency generator is connected to an external antenna, to which the input of the telemetry channel receiver is also connected, the first input of the control programmable microcontroller of the receiver is connected to the antenna of the receiver unit, the first output of the control programmable microcontroller of the receiver is connected to the multi-channel switch through a series-connected digital-to-analog converter and power amplifier , the multi-channel switch is connected by its working inputs and outputs, forming to ontacts of the receiver unit, with the electrodes through the connectors, forming completely independent stimulation channels, configured to be switched on individually, or by any groups, or all at the same time, while the control programmable microcontroller of the receiver is also connected to the multi-channel switch through the second and third inputs, which are telemetry inputs microcontroller of the receiver, respectively, through a current measuring device and directly, and with the antenna of the receiver unit through its telemetric output and connection nenny him shaper of telemetry signals. 2. The electroneurostimulator according to claim 1, characterized in that the control microcontrollers of the transmitter and receiver contain software that implements the function of separate control modes of the electron neurostimulator for the doctor and patient. 3. The electroneurostimulator according to claim 1, characterized in that all the channels contain a limiter that prevents the coincidence of their current stimulating pulses in time. 4. The electroneurostimulator according to claim 1, characterized in that the electrodes are bipolar, quadropolar or multipolar. 5. The electroneurostimulator according to claim 1, characterized in that it is arranged to generate a sequence of biphasic stimulating pulses of any polarity on any pairs of contacts of the receiver unit. 6. The electroneurostimulator according to claim 5, characterized in that it is made with the possibility of discrete regulation of the amplitude of the voltage of the biphasic pulses from -5.0 to +5.0 V in 0.1 V increments, in any channel included. 7. The electroneurostimulator according to claim 5, characterized in that it is configured to generate biphasic pulses with a total voltage amplitude not exceeding 12 V in any channel. 8. The electroneurostimulator according to claim 5, characterized in that it is configured to generate biphasic pulses with a frequency of 1 to 250 Hz, and also with the ability to control the frequency in the range from 1 to 15 Hz in increments of 1 Hz, in the range from 15 to 100 Hz - with a step of 5 Hz, and in the range from 100 to 250 Hz - with a step of 10 Hz, when one or several channels are switched on on any pairs of contacts of the receiver unit. 9. The electroneurostimulator according to claim 5, characterized in that it is made with the possibility of discrete control of the duration of biphasic pulses from 50 to 750 μs in increments of 50 μs, when one or several channels are switched on at any pair of contacts of the receiver unit. 10. The electroneurostimulator according to claim 1, characterized in that it is arranged to generate a sequence of biphase packs of stimulating pulses of any polarity on any pairs of contacts of the receiver unit. 11. The electroneurostimulator according to claim 10, characterized in that it is configured to control the follow-up period of biphasic bursts of pulses from 1 to 255 s when one or several channels are switched on on any pair of contacts of the receiver unit, as well as with the possibility of discrete control of the repetition period 1 s in any of the channels. 12. The electroneurostimulator according to claim 10, characterized in that it is made with the possibility of discrete control of the rise time of the amplitude of the biphasic pulse train from 0 to 15 s with an interval of 1 s in any channel. 13. The electroneurostimulator according to claim 10, characterized in that it is configured to control the slew rate of the amplitude of the biphasic pulse train from 100 to 1500 mV / s in increments of 100 mV / s in any channel. 14. The electroneurostimulator according to claim 10, characterized in that it is arranged to generate biphasic bursts of pulses with a total maximum voltage amplitude not exceeding 12 V.

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