WO2010121353A1

WO2010121353A1 - Device for measuring spasticity in muscles

Info

Publication number: WO2010121353A1
Application number: PCT/CA2010/000550
Authority: WO
Inventors: Julie Bazoge; Anne Marchand
Original assignee: Université de Montréal
Priority date: 2009-04-20
Filing date: 2010-04-20
Publication date: 2010-10-28

Abstract

It is an object of the present invention to provide a portable device for quantitative measurement of spasticity in an articulated limb comprising a measurement module with an articulation angle sensor for measuring an angle about an articulation, the articulation sensor comprising two longitudinal sections that can be adjusted lengthwise with a distal end and a proximal end that attaches to a central hinge and wherein the longitudinal sections comprise a mechanism for securing one side of the articulation to a first longitudinal section and another side of the articulation to a second longitudinal section; a joint angular velocity sensor that measures angular velocity of the first longitudinal section with respect the second longitudinal section; and a muscle activity sensor for measuring electrical activity of the muscle; and a control module comprising a processor that receives joint angle and angular velocity data and is programmed to determine a spasticity value, the control module adapted for receiving user input for performing spasticity measurements and delivering output spasticity results, wherein data from muscle electrical activity, angular velocity and articulation angle are received and pre-processed at said measurement module prior to being transferred to said control module.

Description

DEVICE FOR MEASURING SPASTICITY IN MUSCLES

TECHNICAL FIELD

This invention relates to the field of muscle activity assessment and more specifically to a new device for measuring and/or diagnosing spasticity in muscles.

BACKGROUND OF THE INVENTION

Spasticity is a neurological symptom affecting children and adults causing an abnormal increase in muscle tone that occurs when the affected muscle is stretched. Spasticity can occur in neurological disorders that damage the parts of the brain and the nervous system that control voluntary movements. The most common disorders leading to spasticity are cerebral palsy, spinal cord injury, multiple sclerosis, stroke, and traumatic brain injuries, due to a lack of oxygen, physical trauma, haemorrhage, or infection. Some of these injuries can occur at birth and others can occur during adulthood.

A known prior art apparatus and method for measuring a degree of spasticity in a muscle is found in commonly assigned US Patent Application 11/910,251 filed on November 27, 2007 and was published on September 30, 2006 as WO2006/102764. This prior art apparatus allows for spasticity determinations to be performed in a hospital environment, at the bedside or in the clinic. More specifically, assessment of spasticity is based on the stretch reflex threshold (SRT), which is the joint angle at which the muscle starts to be activated. The SRT is determined using a dynamic approach in which the limb is moved and the angular velocity of the joint is recorded as a function of the angle. For each velocity of stretch, the angle at which the onset of SR is detected is recorded and a regression is performed to obtain the SRT angle at velocity zero. It will also be appreciated that an upper and a lower angular limit may be determined which may serve as a basis, together with the SRT angle, to assess spasticity. One known model of a clinically used apparatus made in accordance with WO2006/102764 has a joint angle sensing device such as a goniometer that send the angle and angular velocity signal to a control and measurement unit. The electromyograph (EMG) signal is also sent to the control and measurement unit with the skin contact electrode wires running from the patient arm or leg to the control and measurement unit. Within this arrangement, there are several physical links between modules/units and between the patient and these modules/units. There are many modules to transport when moving the apparatus around rendering it cumbersome. The accuracy of angular velocity determinations can be compromised if the device is not securely attached to the patient.

This prior art apparatus takes time to install on a patient and several "cold" metal pieces are in contact with the skin of the patient. The straps for attaching the apparatus to the patient are uncomfortable due to their narrow width.

The prior art apparatus has a large footprint due to its multi-module nature and bulky components, and, in a hospital setting, space is a resource that is to be exploited with parsimony. The prior art apparatus has many wires, is difficult to move around and appears somewhat archaic/robotic which may lead to patient unease with respect to its efficacy or safety. This is an important shortcoming as typical patients suffering from spasticity are limited in their mobility.

Because of all the above enumerated drawbacks, it is highly desirable to have a new and improved device for determining spasticity that is designed to overcome all the shortcomings of the prior art apparatus, thereby allowing greater ease to use, and rendering possible home-based spasticity measurements/treatments by a patient

SUMMARY OF THE INVENTION

It has been discovered that pre-processing (including filtering and amplification) of the signal/data from a muscle activity sensor such as an EMG electrode on a limb- mounted spasticity measurement apparatus can simplify the connection of the electrodes to the patient.

It has further been discovered that improved accuracy measurements can be obtained by using an anti-slip material against the patient's limb at the attachment point of a limb-mounted articulation spasticity measurement apparatus semi-flexible section. Linear extension adjustability can be provided, if desired, within the rigid section so as to position the attachment point at a different radius from the pivot point.

It has been discovered that greater ease of use can be achieved by providing a power source for an EMG device on a limb-mounted articulation spasticity measurement apparatus so that EMG data can be acquired entirely by the limb- mounted apparatus, and this data, along with articulation angle and/or velocity data can be stored, locally processed and analyzed, or immediately transmitted to a control module/analyzer.

It is an object of the present invention to provide a portable device for quantitative measurement of spasticity in an articulated limb comprising a measurement module comprising an articulation angle sensor for measuring an angle about an articulation, the articulation sensor comprising two longitudinal sections that can be adjusted lengthwise with a distal end and a proximal end that attaches to a central hinge and wherein the longitudinal sections comprise a mechanism for securing one side of the articulation to a first longitudinal section and another side of the articulation to a second longitudinal section; a joint angular velocity sensor that measures angular velocity of the first longitudinal section with respect the second longitudinal section; and a muscle activity sensor for measuring electrical activity of the muscle; and a control module comprising a processor that receives joint angle and angular velocity data and is programmed to determine a spasticity value, the control module adapted for receiving user input for performing spasticity measurements and delivering output spasticity results. Data from muscle electrical activity, angular velocity and articulation angle are received and processed at said measurement module prior to being transferred to said control module. In some embodiments of the invention, the muscle activity sensor is integrated into either of the first or second longitudinal sections and the mechanism for securing the device to a limb can be adapted to allow efficient attachment to any articulation such as knee, shoulder, ankle, hip, wrist and elbow and a quick release mechanism can allow for easy interchange of longitudinal sections such that different articulations can be evaluated and/or treated.

In yet other embodiments of the invention, the mechanism for further securing the module comprises a first piece characterized in that a semi-flexible band partially surrounds the limb at or near the distal end of each longitudinal section and a second piece that is more adaptable in length selected from a group comprising straps with Velcro™-like material to secure into place, another piece of semi-flexible material with clips, an elastic strap material.

In some embodiments of the invention, an anti-slip material inside the semi-flexible band allows for stability of the measurement module on the articulated limb during movements and wherein the anti-slip material can be textured silicon, rubber, or any other anti-slip material.

In some embodiments of the invention, the device is used for measuring and/or treating spasticity in a limb and in other embodiments of the invention, the device is used exclusively as a goniometer or exclusively as a muscle activity sensor.

In some embodiments of the invention, an accelerometer is provided to measure the articulation angle and the angular velocity about an articulation.

In some embodiments of the invention, the muscle activity sensor is an electromyograph (EMG) and a wireless communication mechanism can allow for wireless communication between the EMG electrodes and the measurement or control modules.

In some embodiments of the invention, there is provided a mechanism for transmitting data wirelessly between the measurement module and the control module. In some embodiments of the invention, there is provided a device for measuring spasticity or diagnosing a disease associated with excessive muscle tone and/or contracture.

In some embodiments of the invention, the hinge is adapted to allow the two longitudinal sections to superimpose, thereby reducing overall size of the measurement module and allowing for easy storage. The hinge can further comprise a rotation mechanism to allow the longitudinal sections to rotate approximately 180 degrees about the longitudinal axis such that the measurement module can be used on either of the right or left limb. In other embodiments of the invention, the bands can be turned to allow use on either right or left articulation.

In some embodiments of the invention, a battery delivers the electrical power required for function.

In some embodiments of the invention, the mechanism for securing the longitudinal section to the limb is made from a band of semi-flexible material that can conform to at least a partial contour of the limb.

In some embodiments of the invention, user input is performed through one of a dial-and-turn, groove-and-clip or hole-and-pin mechanism for telescopically adjusting the length of the longitudinal sections.

In some embodiments of the invention, the inputs are received through any combination of tactile screens, knobs, dials, buttons or voice command, and the outputs can be displayed on a monitor, printed on paper or by vocalized by a computer.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood by way of the following detailed description of embodiments of the invention with reference to the appended drawings, in which: Figure 1 is an illustration of the complete device including the measurement module and the control module.

Figure 2 is an illustration of the measurement module depicting the muscle activity sensor and/or battery separated from the measurement module for recharging or data transfer purposes.

Figure 3 is an illustration of the inside surfaces of the measurement module.

Figure 4 is an illustration of the lengthwise telescopic adjustment mechanism.

Figure 5 is an illustration of a measurement module conforming to an articulated limb during the process of determining spasticity in muscles.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings and for illustrative purposes, the present invention is embodied in the device 10 shown in FIG.1 which illustrates two main modules consisting of a first measurement module 100 and a second control module 200. The device is designed to contain as few modules as possible in order to favour portability. With the high number of device movements both during and between measurement/treatment sessions, it is also designed with as a few wires or visible wires as possible. A data storage module 300 is shown in the illustrated embodiment as a memory drive which can be used to store patient-specific data. Data transfer between measurement and control modules must be in real-time and this can be achieved by wired or wireless data transmission such as BlueTooth™, WiFi™ or other. FIG.1 also depicts the securing mechanism used to secure the module onto an articulated limb. The securing mechanism is shown as bands 130 and straps 110 in this embodiment but it can also be achieved by clips, elastic material or any other mechanisms that insures easy, quick and secure fastening of the measurement module 100 to many articulations of many body types and sizes. Articulation angle and angular velocity are measured with respect to a central hinge 102. In some embodiments, the control module 200 can be part of (or integrated with) the measurement module 100 to further minimize wires and connections and in order to increase simplicity of the device. For example, a small display device and a processor could be integrated to the outside of band 130 or energy source 103.

A band of semi-flexible material 130 such as polyurethane, polypropylene, rubber is designed to espouse only a partial contour of the limb with a strap of seat-belt like material and Velcro™ completing the contour. A band that fully conforms to the complete contour of a limb would not be adaptable to many body sizes and a band mating with less than approximately one quarter (25%) of the contour of the limb would not allow for secure fastening. The securing mechanism 110 and 130 is designed with a combination of straps and semi-flexible material such that it can be used on a 30 lbs toddler and a morbidly obese patient without adaptation.

Furthermore, the partial-straps allow for certain minor adjustments which are necessary when a limb is moved about its articulation 112 (FIG.5).

One way to decrease the shortcomings of wiring is to transmit all signals wirelessly but, alternatively, it is possible to include wire-rolling devices for such wires as those of the EMG electrodes 101. Such wire-rolling devices would help disseminate wires when such a wire 115 not in use and insure having only the minimum length of wiring, thereby eliminating the possibility of entanglement during use or transportation of the spasticity device.

FIG. 5 illustrates the two longitudinal sections 108 and 109 of the measurement module that are on each side of a central hinge-axis 112. For example, if the device is used on the elbow joint as shown in FIG. 5, a first longitudinal section will be secured onto the upper arm 108 (humerus side) of a patient and a second longitudinal section will be secured to the lower arm 109 (radius/ulna side) of a patient. Referring back to FIG. 1 , the measurement module 100 further comprises an energy source 103 such as a battery pack which also serves as the main connector and energy source for powering the electromyography electrodes 101. EMG electrodes can be conveniently plugged into a socket on energy source 103 for easy connection and/or replacement. FIG. 2 depicts an additional view of the measurement device 100 shown in FIG.1 with the energy source 103 removed to show the data capture 107 and data transmittal device 104. The data transmittal device 104 can be embodied by, but should not be understood as being limited to, a memory card slot, USB receiver or a wireless data transmitter. Data from the muscle activity sensors 101 as well as the angular velocity and joint angle sensors reach the data capture device where they are pre-processed (filtered and/or amplified) before reaching the data transmittal device 104 and sent to the control module 200.

FIG. 3 illustrates an inside view of the measurement module 100 to show the additional textured surface 105 provided inside the securing bands 130. This textured surface 105 is added to insure stability of the measurement module 100 on the limb of the patient during experimentation. The textured surface 105 can be made of silicon or any material with anti-slip properties.

FIG. 4 illustrates the measurement module 100, depicting the lengthwise adjustment mechanism 106. This adjustment mechanism can be a dial-and-turn, groove-and-clip or hole-and-pin type mechanism for telescopically adjusting the length of the longitudinal sections. Additionally, the lengthwise adjustment mechanism 106 can be used to change the securing mechanism 110 and 130 to one that is more appropriate for certain articulations. Although not shown in FIG. 4, both longitudinal sections may comprise such a lengthwise adjustment mechanisms, while it is also possible to provide the adjustment on only one longitudinal section, preferably the section 109. As a further alternative, the sections 108 and 109 can be both fixed with the removable energy source 103 being exchangeable between longitudinal sections.

The control module receives a set of data that contains at least muscle activity sensor data, angular velocity sensor data and/or articulation angle sensor data. It is designed with ease of use, accessibility and portability as its main features. The control module 200 is embodied here as a stand-alone module but it can also take the form of software loaded onto a personal computer. The control module can, in some embodiments, display immediate results that are visually easy to interpret. The control module can store patient information. The device as a whole is easy to use and measurements can be performed by a clinician with minimal training. The controls of the device are easy to understand and easy to use. Battery life can be visualized on the control module display and/or a sound prompt can be heard when battery life reaches a certain threshold. The control module and the measurement module can have voice activated commands.

Claims

What is claimed is:

1. A portable device for quantitative measurement of spasticity in an articulated limb comprising:

a measurement module comprising an articulation angle sensor for measuring an angle about an articulation, said articulation angle sensor comprising two longitudinal sections that can be adjusted lengthwise with a distal end and a proximal end that attaches to a central hinge and wherein said longitudinal sections comprise a mechanism for securing one side of the articulation to a first longitudinal section and another side of the articulation to a second longitudinal section; a velocity sensor that measures angular velocity of said first longitudinal section with respect to said second longitudinal section; and a muscle activity sensor for measuring electrical activity of said muscle; and

a control module comprising a processor that receives joint angle and angular velocity data and is programmed to determine a spasticity value, said control module adapted for receiving user input for performing spasticity measurements and delivering output spasticity results; and

wherein data from muscle electrical activity, angular velocity and articulation angle are received and pre-processed at said measurement module prior to being transferred to said control module.

2. The device as claimed in claim 1 wherein said muscle electrical activity sensor is integrated into either of said first or second longitudinal sections.

3. The device as claimed in claim 1 or 2, wherein said mechanism for securing is adapted to allow efficient attachment to an articulation selected from a list comprising knee, shoulder, ankle, hip, wrist and elbow.

4. The device as claimed in any one of claim 1 to 3, further comprising a quick release mechanism to allow easy interchange of said longitudinal sections.

5. The device as claimed in any one of claim 1 to 4, wherein said mechanism for securing further comprises a first piece characterized in that a semi-flexible band partially surrounds the limb at or near the distal end of each longitudinal section and a second piece that is more adaptable in length selected from a group comprising straps with Velcro™-like material to secure into place, another piece of semi-flexible material with clips, an elastic strap material.

6. The device as claimed in any one of claim 1 to 5, further comprising an anti-slip material inside said semi-flexible band to allow stability of said measurement module on said articulated limb during movements.

7. The device as claimed in claim 6, wherein at anti-slip material is one or any combination of textured silicon, rubber and polyurethane.

8. The device as claimed in any one of claim 1 to 7, further comprising an accelerometer to measure said articulation angle and said angular velocity about an articulation.

9. The device as claimed in any one of claim 1 to 8, wherein the muscle activity sensor is an electromyograph (EMG).

10. The device as claimed in any one of claim 1 to 9, further comprising a wireless communication mechanism between said EMG electrodes and said control module.

11. The device as claimed in any one of claim 1 to 10, further comprising a mechanism for transmitting data wirelessly between said control module and said measurement module.

12. Use of the device as claimed in any one of claim 1 to 11 , wherein said device is used exclusively as a muscle activity sensor.

13. A device as claimed in any one of claim 1 to 12, wherein said hinge is adapted to allow said two longitudinal sections to superimpose, thereby reducing overall size of the measurement module and allowing easy storage.

14. A device as claimed in any one of claim 1 to 13, wherein said hinge further comprises a rotation mechanism to allow the longitudinal sections to rotate approximately 180 degrees about the longitudinal axis such that the measurement module can be used on either of the right or left articulation.

15. A device as claimed in any one of claim 1 to 14, wherein said bands can be turned to allow use on either right or left articulation

16. A device as claimed in any one of claim 1 to 15, further comprising a battery to deliver electrical power required for functioning.

17. A device as claimed in any one of claim 1 to 16, wherein said mechanism for securing the longitudinal section to the limb is made from a band of semi-flexible material that can conform to at least a partial contour of the limb.

18. A device as claimed in any one of claim 1 to 17, further comprising one of a dial- and-turn, groove-and-clip or hole-and-pin mechanism for telescopically adjusting the length of the longitudinal sections.

19. A device as claimed in any one of claim 1 to 18, wherein said inputs are received through any one or combination of tactile screens, knobs, dials, buttons or voice command.

20. A device as claimed in any one of claim 1 to 19, wherein said output is displayed on a monitor, printed on paper or vocalized by a computer.

21. A device as claimed in any one of claim 1 to 20, wherein the control module is a personal computer such as a desktop or laptop computer.

22. A device as claimed in any one of claim 1 to 21 , wherein said control module is part of said measurement module.

23. Use of a device as claimed in any one of claim 1 to 22 for measuring spasticity in a limb.

24. Use of a device as claimed in any one of claim 1 to 22 for diagnosing spasticity in a limb.

25. Use of a device as claimed in any one of claim 1 to 22 for diagnosing neuromuscular disorders.

26. Use of the device of any one of claim 1 to 22, wherein said disease comprises at least one of multiple sclerosis, cerebral palsy, stroke, traumatic brain injury and spinal cord injury.

27. Use of a device as claimed in any one of claim 1 to 22, wherein said device is used exclusively as a joint angle sensing device such as a goniometer.