Muscle stimulation method and system to improve walking

• US 20070179561A1
• Filed: 01/31/2006
• Published: 08/02/2007
• Est. Priority Date: 01/31/2006
• Status: Active Grant

• Current Assignee: Good Samaritan Children's Therapy Unit
• Original Assignee: Good Samaritan Children's Therapy Unit
• Inventors: Augsburger, Samuel, Embrey, David
• Granted Patent: US 7,756,585 B2
• Time in Patent Office: Days
• US Class Current: 607/49
• CPC Class Codes: A61N 1/36003 of motor muscles, e.g. for walking assistance

Abstract

In a method and a system of providing walking assistance and/or therapy to a person with impaired gait, electrical stimulation is applied to muscles of a leg that effect dorsiflexion and plantar flexion of the ankle of the leg. The timing of the electrical stimulation is determined from gait event signals developed from sensors under the heel and forepart of the foot of the other leg. In the method and the system, the electrical stimulation is enabled when the person is sensed to be active and is disabled when the person is sensed to be inactive. The method and the system are applicable to persons having unilateral or bilateral impairment of their walking ability.

Claims

1. A method of providing walking assistance and/or therapy to a person with impaired gait, the method comprising the steps of:

developing first gait event signals in response to pressure sensed between the heel of the foot of one leg and a support surface while walking;

developing second gait event signals in response to pressure sensed between the forepart of the foot of the one leg and the support surface while walking;

applying electrical stimulation to at least one muscle in the other leg that effects dorsiflexion of the ankle of the other leg in response to at least one of the first and second gait event signals; and

applying electrical stimulation to at least one muscle in the other leg that effects plantar flexion of the ankle of the other leg when both of the first and second gait event signals are absent.

2. The method as recited in claim 1, wherein the first and second gait event signals are developed from electrical switches located under the heel and forepart, respectively, of the foot of the one leg.

3. The method as recited in claim 1, and further comprising the steps of:

developing an activity signal in response to sensed movement of the person;

allowing the transmission of electrical stimulation to the muscles in response to the activity signal; and

blocking the transmission of electrical stimulation to the muscles when the activity signal is absent.

4. The method as recited in claim 3, wherein:

the activity signal is developed in response to movement of the person along each of two orthogonal axes.

5. The method as recited in claim 1, wherein:

first gait event signals are developed in response to pressure sensed between the heel of the foot of each leg and a support surface while walking;

second gait event signals are developed in response to pressure sensed between the forepart of the foot of each leg and the support surface while walking;

electrical stimulation is applied to at least one muscle in each leg that effects dorsiflexion of the ankle of the leg in response to at least one of the first and second gait event signals derived from the other leg; and

electrical stimulation is applied to at least one muscle in each leg that effects plantar flexion of the ankle of the leg when both of the first and second gait event signals derived from the other leg are absent.

6. The method as recited in claim 5, wherein the first and second gait event signals are developed from electrical switches located under the heel and forepart, respectively, of the foot of each leg.

7. The method as recited in claim 5, and further comprising the steps of:

developing an activity signal in response to sensed movement of the person;

allowing the transmission of electrical stimulation to the muscles in response to the activity signal; and

blocking the transmission of electrical stimulation to the muscles when the activity signal is absent.

8. The method as recited in claim 7, and further comprising the steps of:

the activity signal is developed in response to movement of the person along each of two orthogonal axes.

9. A system for providing walking assistance and/or therapy to a person with impaired gait, the system comprising:

a first sensor for developing a first gait event signal in response to pressure sensed between the heel of the foot of one leg and a support surface while walking;

a second sensor for developing a second gait event signal in response to pressure sensed between the forepart of the foot of the one leg and the support surface while walking; and

at least one pair of first electrodes for applying electrical stimulation to at least one muscle in the other leg that effects dorsiflexion of the ankle of the other leg;

at least one pair of second electrodes for applying electrical stimulation to at least one muscle in the other leg that effects plantar flexion of the ankle of the other leg; and

an electrical stimulation device configured to receive the first and second gait event signals and provide an electrical stimulation output to the electrodes, the electrical stimulation device providing (1) an electrical stimulation output to the at least one pair of first electrodes in response to the reception of at least one of the first and second gait event signals and (2) an electrical stimulation output to the at least one pair of second electrodes when both of the first and second gait event signals are absent.

10. The system as recited in claim 9, wherein the first and second sensors are electrical switches located under the heel and forepart, respectively, of the foot of the one leg.

11. The system as recited in claim 10, wherein the switches are connected in parallel electrically between electrical conductors providing an input to the electrical stimulation device.

12. The system as recited in claim 9, and further comprising:

a third sensor for developing an activity signal in response to sensed activity of the person; and

a control device that (1) allows the transmission of electrical stimulation to the muscles in response to the activity signal and (2) blocks the transmission of electrical stimulation to the muscles when the activity signal is absent.

13. The system as recited in claim 12, wherein the third sensor is an accelerometer carried by the person.

14. The system as recited in claim 13, wherein the accelerometer senses accelerations occurring along each of two orthogonal axes.

15. The system as recited in claim 9, wherein:

first sensors are provided for developing first gait event signals in response to pressure sensed between the heel of the foot of each leg and a support surface while walking;

second sensors are provided for developing second gait event signals in response to pressure sensed between the forepart of the foot of each leg and the support surface while walking;

at least one pair of first electrodes is provided for each leg;

at least one pair of second electrodes is provided for each leg; and

the electrical stimulation device is configured to receive the first and second gait event signals derived from each leg and provide an electrical stimulation output to the electrodes, the electrical stimulation device providing (1) an electrical stimulation output to the at least one pair of first electrodes of one leg in response to the reception of at least one of the first and second gait event signals derived from the other leg and (2) an electrical stimulation output to the at least one pair of second electrodes of one leg when both of the first and second gait event signals derived from the other leg are absent.

16. The system as recited in claim 15, wherein the first and second sensors are electrical switches located under the heel and forepart, respectively, of the foot of each leg.

17. The system as recited in claim 16, wherein the switches under the foot of one leg are connected in parallel electrically between electrical conductors providing an input to the electrical stimulation device, and the switches under the foot of the other leg are connected in parallel electrically between electrical conductors providing another input to the electrical stimulation device.

18. The system as recited in claim 15, and further comprising:

a third sensor for developing an activity signal in response to sensed activity of the person; and

a control device that (1) allows the transmission of electrical stimulation to the muscles in response to the activity signal and (2) blocks the transmission of electrical stimulation to the muscles when the activity signal is absent.

19. The system as recited in claim 18, wherein the third sensor is an accelerometer carried by the person.

20. The system as recited in claim 19, wherein the accelerometer senses accelerations occurring along each of two orthogonal axes.