Actuation and control of limbs through motor nerve stimulation

• US 20020161415A1
• Filed: 04/26/2001
• Published: 10/31/2002
• Est. Priority Date: 04/26/2001
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: BioControl Medical (B.C.M) Ltd.
• Inventors: Cohen, Ehud, Gross, Yossi
• Granted Patent: US 6,839,594 B2
• Time in Patent Office: Days
• US Class Current: 607/48
• CPC Class Codes: A61N 1/36003 of motor muscles, e.g. for walking assistance
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula

Abstract

Apparatus for actuating a skeletal muscle of a patient is provided. The apparatus typically includes a plurality of electrodes, which are adapted to be placed in a vicinity of a motor nerve that innervates the skeletal muscle. A control unit, is preferably adapted to drive a current between two or more of the plurality of electrodes, and to configure the current such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

Claims

1. Apparatus for actuating a skeletal muscle of a patient, comprising:

a plurality of electrodes, which are adapted to be placed in a vicinity of a motor nerve that innervates the skeletal muscle; and

a control unit, which is adapted to drive a current between two or more of the plurality of electrodes, and to configure the current such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

2. Apparatus according to claim 1, wherein the plurality of electrodes comprises at least 15 electrodes.

3. Apparatus according to claim 1, wherein at least two of the plurality of electrodes are spaced less than 2 mm apart.

4. Apparatus according to claim 1, wherein the plurality of electrodes are adapted to be implanted in the patient and to be placed in contact with the motor nerve.

5. Apparatus according to claim 1, wherein the plurality of electrodes are adapted to be disposed around the motor nerve.

6. Apparatus according to claim 1, wherein the control unit is adapted to configure the current such that the skeletal muscle is induced to contract responsive to the current, and such that another skeletal muscle of the patient, which other skeletal muscle is innervated by the second subset of axons, substantially does not contract responsive to the current.

7. Apparatus according to claim 1, wherein the plurality of electrodes includes a first set of electrodes,

wherein the motor nerve includes a first motor nerve,

wherein the skeletal muscle includes a first skeletal muscle,

wherein the apparatus comprises a second set of electrodes, which are adapted to be placed in a vicinity of a second motor nerve, which second motor nerve innervates a second skeletal muscle, and

wherein the control unit is adapted to drive respective first and second currents through the first and second sets of electrodes, so as to induce a coordinated movement of a limb controlled by the first and second muscles.

8. Apparatus according to claim 1, wherein the control unit is adapted to drive respective first and second currents through the plurality of electrodes, responsive to respective first and second sets of stimulation parameters adapted to induce modulation of respective first and second sets of axons in the motor nerve, so as to induce a coordinated movement of a limb having one or more muscles innervated by the motor nerve.

9. Apparatus according to claim 1, wherein the control unit is adapted to drive the current using a first set of stimulation parameters in order to induce contraction of a first set of muscle fibers in a muscle innervated by the nerve, and, subsequent thereto, to drive the current using a second set of stimulation parameters, in order to induce contraction of a second set of muscle fibers in the muscle.

10. Apparatus according to claim 9, wherein the control unit is adapted to cycle between applying the current using the first set of stimulation parameters and applying the current using the second set of stimulation parameters, in accordance with a schedule determined to reduce fatigue of the muscle.

11. Apparatus according to claim 1, and comprising a user-interface unit, which is adapted to convey an instruction from the patient to the control unit.

12. Apparatus according to claim 11, wherein the user-interface unit is adapted to communicate with the control unit by means of wireless communication.

13. Apparatus according to claim 11, wherein the user-interface unit is adapted to receive the instruction by means of a voice command from the patient.

14. Apparatus according to claim 11, wherein the user-interface unit comprises an eye-blink sensor, which is adapted to detect eye-blinking by the patient, and wherein the user-interface unit is adapted to convey the instruction responsive to an output of the eye-blink sensor.

15. Apparatus according to claim 11, wherein the user-interface unit comprises a pupil tracking unit, which is adapted to detect movement of a pupil of an eye of the patient, and wherein the user-interface unit is adapted to convey the instruction responsive to an output of the pupil tracking unit.

16. Apparatus according to claim 11, wherein the user-interface unit comprises:

a focused-energy source, adapted to be directed by the patient at a target; and

an energy detector, adapted to detect energy generated by the source and reflected by the target, and adapted to generate a detector signal responsive to the detected energy,

wherein the control unit is adapted to receive the detector signal, to analyze the detector signal, and to drive the current responsive to analyzing the detector signal.

17. Apparatus according to claim 16, wherein the focused-energy source comprises a laser.

18. Apparatus according to claim 16, wherein the focused-energy source comprises an ultrasound source.

19. Apparatus according to claim 1, and comprising a disposition sensor, which is adapted to generate a disposition sensor signal responsive to a disposition of a limb of the patient which includes the skeletal muscle, wherein the control unit is adapted to analyze the disposition sensor signal and to drive the current responsive to analyzing the signal.

20. Apparatus according to claim 19, wherein the sensor comprises an accelerometer.

21. Apparatus according to claim 19, wherein the sensor comprises a three-axis accelerometer.

22. Apparatus according to claim 19, wherein the sensor comprises a sensing electrode, adapted to sense a contraction of the skeletal muscle.

23. Apparatus according to claim 19, wherein the sensor comprises a video imaging unit.

24. Apparatus according to claim 19, wherein the sensor comprises an ultrasound transducer.

25. Apparatus according to claim 19, wherein the sensor comprises a force transducer.

26. Apparatus according to claim 19, wherein the sensor comprises a piezoelectric element.

27. Apparatus according to claim 19, wherein the sensor comprises a goniometer.

28. Apparatus according to claim 19, wherein the disposition sensor includes a first disposition sensor which is adapted to generate a first disposition sensor signal,

wherein the limb includes a first limb,

wherein the apparatus comprises a second disposition sensor, adapted to generate a second disposition sensor signal responsive to a disposition of a second limb of the patient, the second limb being contralateral to the first limb, and

wherein the control unit is adapted to analyze the first and second disposition sensor signals and to drive the current responsive to analyzing the signals.

29. Apparatus according to claim 19, wherein the apparatus comprises a glove designated to be worn on a hand of the patient,

wherein the glove comprises a plurality of disposition sensors which are adapted to generate respective disposition sensor signals responsive to dispositions of respective portions of the hand, and

wherein the control unit is adapted to drive the current responsive to the plurality of disposition sensor signals.

30. Apparatus according to claim 19, wherein the control unit is adapted to analyze the disposition sensor signal using an artificial neural network algorithm.

31. Apparatus according to claim 19, wherein the control unit is adapted to modify a frequency of the current responsive to analyzing the disposition sensor signal.

32. Apparatus according to claim 19, wherein the control unit is adapted to modify an amplitude of the current responsive to analyzing the disposition sensor signal.

33. Apparatus according to claim 19, wherein the control unit is adapted to modify a duration of the current responsive to analyzing the disposition sensor signal.

35. Apparatus according to claim 34, wherein the control unit is adapted to configure the field such that the skeletal muscle is induced to contract responsive to the induced current, and such that another skeletal muscle of the patient, which other skeletal muscle is innervated by the second subset of axons, substantially does not contract responsive to the induced current.

36. Apparatus according to claim 34, and comprising a user-interface unit, which is adapted to convey an instruction from the patient to the control unit.

37. Apparatus according to claim 34, and comprising a disposition sensor, which is adapted to generate a disposition sensor signal responsive to a disposition of a limb of the patient which includes the skeletal muscle, wherein the control unit is adapted to analyze the disposition sensor signal and to modify the field responsive to analyzing the signal.

39. Apparatus according to claim 38, wherein the control unit is adapted to configure the current such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

40. Apparatus according to claim 38, wherein the disposition sensor is adapted to generate the disposition sensor signal responsive to a tremor of the limb.

41. Apparatus according to claim 38, wherein the one or more electrodes include a first set of electrodes,

wherein the motor nerve includes a first motor nerve,

wherein the skeletal muscle includes a first skeletal muscle,

wherein the apparatus comprises a second set of electrodes, which are adapted to be placed in a vicinity of a second motor nerve, which second motor nerve innervates a second skeletal muscle, and

wherein the control unit is adapted to drive respective first and second currents through the first and second sets of electrodes, responsive to the disposition sensor signal, so as to induce a coordinated movement of the limb.

42. Apparatus according to claim 38, wherein the sensor comprises an accelerometer.

43. Apparatus according to claim 38, wherein the sensor comprises a three-axis accelerometer.

44. Apparatus according to claim 38, wherein the sensor comprises a sensing electrode, adapted to sense a contraction of the skeletal muscle.

45. Apparatus according to claim 38, wherein the sensor comprises a video imaging unit.

46. Apparatus according to claim 38, wherein the sensor comprises an ultrasound transducer.

47. Apparatus according to claim 38, wherein the sensor comprises a force transducer.

48. Apparatus according to claim 38, wherein the sensor comprises a piezoelectric element.

49. Apparatus according to claim 38, wherein the sensor comprises a goniometer.

50. Apparatus according to claim 38, wherein the disposition sensor includes a first disposition sensor which is adapted to generate a first disposition sensor signal,

wherein the limb includes a first limb,

wherein the apparatus comprises a second disposition sensor, adapted to generate a second disposition sensor signal responsive to a disposition of a second limb of the patient, the second limb being contralateral to the first limb, and

wherein the control unit is adapted to analyze the first and second disposition sensor signals and to drive the one or more electrodes to apply the current responsive to analyzing the signals.

51. Apparatus according to claim 38, wherein the apparatus comprises a glove designated to be worn on a hand of the patient,

wherein the glove comprises a plurality of disposition sensors which are adapted to generate respective disposition sensor signals responsive to dispositions of respective portions of the hand, and

wherein the control unit is adapted to drive the one or more electrodes to apply the current responsive to the disposition sensor signals.

52. Apparatus according to claim 38, wherein the control unit is adapted to analyze the disposition sensor signal using an artificial neural network algorithm.

53. Apparatus according to claim 38, wherein the control unit is adapted to modify a frequency of the current responsive to analyzing the disposition sensor signal.

54. Apparatus according to claim 38, wherein the control unit is adapted to modify an amplitude of the current responsive to analyzing the disposition sensor signal.

55. Apparatus according to claim 38, wherein the control unit is adapted to modify a duration of the current responsive to analyzing the disposition sensor signal.

56. Apparatus according to claim 38, wherein the control unit is adapted to drive first and second ones of the one or more electrodes to apply respective first and second electrical signals to the nerve responsive to analyzing the disposition sensor signal.

57. Apparatus according to claim 38, and comprising a user-interface unit, which is adapted to convey an instruction from the patient to the control unit.

58. Apparatus according to claim 57, wherein the user-interface unit is adapted to communicate with the control unit by means of wireless communication.

59. Apparatus according to claim 57, wherein the user-interface unit is adapted to receive the instruction by means of a voice command from the patient.

60. Apparatus according to claim 57, wherein the user-interface unit comprises an eye-blink sensor, which is adapted to detect eye-blinking by the patient, and wherein the user-interface unit is adapted to convey the instruction responsive to an output of the eye-blink sensor.

61. Apparatus according to claim 57, wherein the user-interface unit comprises a pupil tracking unit, which is adapted to detect movement of a pupil of an eye of the patient, and wherein the user-interface unit is adapted to convey the instruction responsive to an output of the pupil tracking unit.

62. Apparatus according to claim 57, wherein the user-interface unit comprises:

a focused-energy source, adapted to be directed by the patient at a target; and

an energy detector, adapted to detect energy generated by the source and reflected by the target, and adapted to generate a detector signal responsive to the detected energy,

wherein the control unit is adapted to receive the detector signal, to analyze the detector signal, and to drive the one or more electrodes to apply the current responsive to analyzing the detector signal.

63. Apparatus according to claim 62, wherein the focused-energy source comprises a laser.

64. Apparatus according to claim 62, wherein the focused-energy source comprises an ultrasound source.

34. Apparatus for actuating a skeletal muscle of a patient, comprising:

a plurality of electromagnetic elements, which are adapted to be placed in a vicinity of a motor nerve that innervates the skeletal muscle; and

a control unit, which is adapted to drive the electromagnetic elements to generate a varying magnetic field that induces an electric current in the motor nerve, and to configure the field such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

38. Apparatus for controlling a limb of a patient, comprising:

one or more electrodes, which are adapted to be placed in a vicinity of a motor nerve that innervates a skeletal muscle that controls the limb;

a disposition sensor, which is adapted to generate a disposition sensor signal responsive to an actual disposition of the limb; and

a control unit, which is adapted to receive the disposition sensor signal, to determine, responsive thereto, the actual disposition of the limb, and to drive the one or more electrodes to apply a current to the nerve, configured such that application thereof induces a contraction of the skeletal muscle which reduces a difference between a desired disposition of the limb and the actual disposition of the limb.

65. Apparatus for treating tremor of a muscle, comprising:

a plurality of electrodes, which are adapted to be placed in a vicinity of a nerve that innervates the muscle;

a sensor, which is adapted to generate a signal responsive to tremor of the muscle; and

a control unit, which is adapted to receive the signal and, responsive thereto, drive the electrodes to apply a current to the nerve, configured so as to stimulate afferent axons of the nerve.

66. Apparatus according to claim 65, wherein the sensor comprises one of the plurality of electrodes.

67. Apparatus according to claim 65, wherein the plurality of electrodes are adapted to be disposed at respective sites along the length of the nerve.

68. Apparatus according to claim 67, wherein the control unit is adapted to drive the electrodes in a sequence responsive to the proximity of each electrode to a brain of a subject having the tremor.

69. Apparatus according to claim 65, wherein the sensor comprises at least one electromyographic (EMG) electrode.

70. Apparatus according to claim 69, wherein the at least one EMG electrode comprises two EMG electrodes, respectively adapted to be coupled to sense electrical activity of the muscle and a muscle antagonistic thereto.

71. A method for actuating a skeletal muscle of a patient, comprising:

driving a current into a motor nerve that innervates the skeletal muscle; and

configuring the current such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

72. A method according to claim 71, wherein configuring the current comprises configuring the current such that the skeletal muscle is induced to contract responsive to the current, and such that another skeletal muscle of the patient, which other skeletal muscle is innervated by the second subset of axons, substantially does not contract responsive to the current.

73. A method according to claim 71, wherein the motor nerve includes a first motor nerve,

wherein the skeletal muscle includes a first skeletal muscle,

wherein driving the current comprises driving a current into a second motor nerve, which second motor nerve innervates a second skeletal muscle, and

wherein configuring the current comprises configuring the currents driven into the first and second muscles, so as to induce a coordinated movement of a limb controlled by the first and second muscles.

74. A method according to claim 71, wherein driving the current comprises driving respective first and second currents, responsive to respective first and second sets of stimulation parameters adapted to induce modulation of respective first and second sets of axons in the motor nerve, so as to induce a coordinated movement of a limb having one or more muscles innervated by the motor nerve.

75. A method according to claim 71, wherein driving the current comprises:

driving the current using a first set of stimulation parameters in order to induce contraction of a first set of muscle fibers in a muscle innervated by the nerve; and

subsequent thereto, driving the current using a second set of stimulation parameters, in order to induce contraction of a second set of muscle fibers in the muscle.

76. A method according to claim 75, and comprising cycling between the steps of driving the current using the first set of stimulation parameters and driving the current using the second set of stimulation parameters, in accordance with a schedule determined to reduce fatigue of the muscle.

77. A method according to claim 71, and comprising receiving an instruction from the patient, wherein configuring the current comprises configuring the current responsive to the instruction.

78. A method according to claim 77, wherein receiving the instruction comprises receiving the instruction by means of wireless communication.

79. A method according to claim 77, wherein receiving the instruction comprises inputting a voice command from the patient.

80. A method according to claim 77, wherein receiving the instruction comprises detecting eye-blinking by the patient.

81. A method according to claim 77, wherein receiving the instruction comprises detecting movement of a pupil of an eye of the patient.

82. A method according to claim 77, wherein receiving the instruction comprises detecting energy directed by the patient at a target and reflected therefrom.

83. A method according to claim 82, wherein detecting the energy comprises detecting energy generated by a laser.

84. A method according to claim 82, wherein detecting the energy comprises detecting ultrasonic energy.

85. A method according to claim 71, and comprising sensing a disposition of a limb of the patient which includes the skeletal muscle, wherein configuring the current comprises configuring the current responsive to the disposition.

86. A method according to claim 85, wherein sensing the disposition comprises sensing an acceleration of the limb.

87. A method according to claim 85, wherein sensing the disposition comprises sensing, at generally the same time, three axes of acceleration of the limb.

88. A method according to claim 85, wherein sensing the disposition comprises sensing a physiological electric current generated during a contraction of the skeletal muscle.

89. A method according to claim 85, wherein sensing the disposition comprises taking video images of the limb.

90. A method according to claim 85, wherein sensing the disposition comprises sensing ultrasonic energy.

91. A method according to claim 85, wherein sensing the disposition comprises sensing a force generated responsive to the disposition of the limb.

92. A method according to claim 85, wherein sensing the disposition comprises sensing a piezoelectrically-generated current.

93. A method according to claim 85, wherein sensing the disposition comprises sensing an angular disposition of a joint of the limb.

94. A method according to claim 85, wherein the limb includes a first limb, wherein the method comprises sensing a disposition of a second limb of the patient, the second limb being contralateral to the first limb, and wherein configuring the current comprises configuring the current responsive to the disposition of the second limb.

95. A method according to claim 85, wherein configuring the current comprises configuring the current responsive to an output of an artificial neural network algorithm.

96. A method according to claim 85, wherein configuring the current comprises modifying a frequency of the current responsive to the disposition.

97. A method according to claim 85, wherein configuring the current comprises modifying an amplitude of the current responsive to the disposition.

98. A method according to claim 85, wherein configuring the current comprises modifying a duration of the current responsive to the disposition.

99. A method for actuating a skeletal muscle of a patient, comprising:

generating a varying magnetic field that induces an electric current in a motor nerve that innervates the skeletal muscle; and

configuring the field such that a first subset of axons in the nerve is excited by the current and such that a second subset of axons in the nerve is not excited by the current.

100. A method according to claim 99, wherein configuring the field comprises configuring the field such that the skeletal muscle is induced to contract responsive to the current, and such that another skeletal muscle of the patient, which other skeletal muscle is innervated by the second subset of axons, substantially does not contract responsive to the current.

101. A method according to claim 99, and comprising receiving an instruction from the patient, wherein configuring the field comprises configuring the field responsive to the instruction.

102. A method according to claim 99, and comprising sensing a disposition of a limb of the patient which includes the skeletal muscle, wherein configuring the field comprises configuring the field responsive to the disposition.

103. A method for controlling a limb of a patient, comprising:

sensing an actual disposition of the limb; and

driving a current into a motor nerve that innervates a skeletal muscle that controls the limb; and

configuring the current to induce a contraction of the skeletal muscle which reduces a difference between a desired disposition of the limb and the actual disposition of the limb.

104. A method according to claim 103, wherein configuring the current comprises configuring the current to excite a first subset of axons in the nerve and to substantially avoid exciting a second subset of axons in the nerve.

105. A method according to claim 103, wherein sensing the disposition comprises sensing a tremor of the limb.

106. A method according to claim 103, wherein the motor nerve includes a first motor nerve,

wherein the skeletal muscle includes a first skeletal muscle,

wherein driving the current comprises driving a current into a second motor nerve, which second motor nerve innervates a second skeletal muscle, and

wherein configuring the current comprises configuring the currents driven into the first and second muscles, so as to induce a coordinated movement of the limb.

107. A method according to claim 103, wherein sensing the disposition comprises sensing an acceleration of the limb.

108. A method according to claim 103, wherein sensing the disposition comprises sensing, at generally the same time, three axes of acceleration of the limb.

109. A method according to claim 103, wherein sensing the disposition comprises sensing a physiological electric current generated during a contraction of the skeletal muscle.

110. A method according to claim 103, wherein sensing the disposition comprises taking video images of the limb.

111. A method according to claim 103, wherein sensing the disposition comprises sensing ultrasonic energy.

112. A method according to claim 103, wherein sensing the disposition comprises sensing a force generated responsive to the disposition of the limb.

113. A method according to claim 103, wherein sensing the disposition comprises sensing a piezoelectrically-generated current.

114. A method according to claim 103, wherein sensing the disposition comprises sensing an angular disposition of a joint of the limb.

115. A method according to claim 103, wherein the limb includes a first limb, wherein the method comprises sensing a disposition of a second limb of the patient, the second limb being contralateral to the first limb, and wherein configuring the current comprises configuring the current responsive to the disposition of the second limb.

116. A method according to claim 103, wherein configuring the current comprises configuring the current responsive to an output of an artificial neural network algorithm.

117. A method according to claim 103, wherein configuring the current comprises modifying a frequency of the current responsive to the disposition.

118. A method according to claim 103, wherein configuring the current comprises modifying an amplitude of the current responsive to the disposition.

119. A method according to claim 103, wherein configuring the current comprises modifying a duration of the current responsive to the disposition.

120. A method according to claim 103, and comprising receiving an instruction from the patient, wherein configuring the current comprises configuring the current responsive to the instruction.

121. A method according to claim 120, wherein receiving the instruction comprises receiving the instruction by means of wireless communication.

122. A method according to claim 120, wherein receiving the instruction comprises inputting a voice command from the patient.

123. A method according to claim 120, wherein receiving the instruction comprises detecting eye-blinking by the patient.

124. A method according to claim 120, wherein receiving the instruction comprises detecting movement of a pupil of an eye of the patient.

125. A method according to claim 120, wherein receiving the instruction comprises detecting energy directed by the patient at a target and reflected therefrom.

126. A method according to claim 125, wherein detecting the energy comprises detecting energy generated by a laser.

127. A method according to claim 125, wherein detecting the energy comprises detecting ultrasonic energy.

129. A method according to claim 128, wherein sensing the tremor comprises detecting electrical activity of the nerve.

130. A method according to claim 128, wherein sensing the tremor comprises detecting electrical activity of the muscle.

131. A method according to claim 130, wherein detecting the electrical activity of the muscle comprises detecting electrical activity of the muscle and of a muscle antagonistic thereto.

132. A method according to claim 128, wherein applying the current comprises applying the current at respective sites along the length of the nerve.

133. A method according to claim 132, wherein applying the current at the respective sites comprises applying the current in a sequence, responsive to the proximity of each site to a brain of a subject having the tremor.

128. A method for treating tremor of a muscle, comprising:

sensing tremor of the muscle; and

responsive thereto, applying a current to a nerve that innervates the muscle, configured so as to stimulate afferent axons of the nerve.