Peripheral Nerve Field Stimulation Control

• US 20090281594A1
• Filed: 01/23/2009
• Published: 11/12/2009
• Est. Priority Date: 05/09/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Wacnik, Paul W., Goetz, Steven M., Heruth, Kenneth T., Lent, Mark S., Keacher, Jeffrey T., Houchins, Andrew H., King, Gary W., Greenberg, Jordan J.
• Granted Patent: US 8,805,518 B2
• Time in Patent Office: Days
• US Class Current: 607/46
• CPC Class Codes: A61N 1/36057 adapted for stimulating afferent nerves
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36139 with automatic adjustment

Abstract

Peripheral nerve field stimulation (PNFS) may be controlled based on detected physiological effects of the PNFS, which may be an efferent response to the PNFS. In some examples, a closed-loop therapy system may include a sensing module that senses a physiological parameter of the patient, which may be indicative of the patient'"'"'s response to the PNFS. Based on a signal generated by the sensing module, the PNFS may be activated, deactivated or modified. Example physiological parameters of the patient include heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex, or thermal activity of the patient'"'"'s body. In some examples, a patient pain state may be detected based on a signal generated by the sensing module, and therapy may be controlled based on the detection of the pain state.

Claims

1. A method comprising:

delivering peripheral nerve field stimulation to a region of a body of a patient in which the patient experiences pain via at least one electrode implanted in the region;

receiving a signal indicative of a physiological parameter of the patient, wherein the signal indicates a response of the patient to the peripheral nerve field stimulation; and

controlling the delivery of the peripheral nerve field stimulation based on the signal.

2. The method of claim 1, wherein delivering peripheral nerve field stimulation comprises delivering electrical stimulation therapy to activate sensory afferent nerve fibers of the patient.

3. The method of claim 1, wherein the response comprises an efferent response.

4. The method of claim 1, wherein receiving the signal comprises receiving the signal that is indicative of at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

5. The method of claim 1, wherein delivering peripheral nerve field stimulation comprises delivering peripheral nerve field stimulation according to a therapy program defining values for a plurality of therapy parameters, and controlling the delivery of peripheral nerve field stimulation comprises automatically modifying a value of at least one of the therapy parameters.

6. The method of claim 1, wherein delivering peripheral nerve field stimulation comprises delivering peripheral nerve field stimulation according to a first therapy program, and controlling the delivery of peripheral nerve field stimulation comprises selecting a second therapy program and initiating the delivery of peripheral nerve field stimulation according to the second therapy program.

7. The method of claim 1, wherein controlling the delivery of the peripheral nerve field stimulation comprises deactivating the delivery of the peripheral nerve field stimulation.

8. The method of claim 1, wherein controlling the delivery of the peripheral nerve field stimulation comprises initiating the delivery of the peripheral nerve field stimulation.

9. The method of claim 1, further comprising comparing an amplitude of the signal to a threshold value, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the comparison between the amplitude of the signal and the threshold value.

10. The method of claim 9, wherein the threshold value is determined based on patient input that indicates an acceptable or unacceptable physiological effect of the delivery of peripheral nerve field stimulation.

11. The method of claim 1, further comprising comparing a pattern of a waveform of the signal to a template, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the comparison between the pattern of the waveform of the signal and the template.

12. The method of claim 1, further comprising determining a first frequency component of a waveform of the signal and comparing the first frequency component to a second frequency component of a waveform template, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the comparison between the first and second frequency components.

13. The method of claim 1, wherein the signal comprises a first signal, the method further comprising:

receiving a second signal indicative of the physiological parameter of the patient; and

comparing a first characteristic of the first signal to a second characteristic of the second signal, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the comparison of the first and second characteristics.

14. The method of claim 13, wherein second signal changes as a function of the physiological parameter of the patient outside of the region of the body in which the patient experiences pain.

15. The method of claim 13, further comprising determining the first characteristic and the second characteristic, the first and second characteristics comprising at least one of an amplitude value, an energy level within a frequency band of the respective first or second signals or a pattern in a waveform of the respective first or second signals.

16. The method of claim 1, wherein the signal comprises a first signal, the method further comprising receiving a second signal indicative of a second physiological parameter of the patient, wherein the second signal indicates the response of the patient to the peripheral nerve field stimulation, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the first and second signals.

17. The method of claim 16, wherein controlling the delivery of the peripheral nerve field stimulation based on the first and second signals comprises controlling the delivery of the peripheral nerve field stimulation to maintain a first characteristic of the first signal within a first range of values and maintain a second characteristic of the second signal within a second range of values.

18. A method comprising:

delivering peripheral nerve field stimulation to a region of a body of a patient in which the patient experiences pain via at least one electrode implanted in the region;

detecting an efferent response of the patient to the delivery of peripheral nerve field stimulation; and

controlling the delivery of electrical stimulation therapy based on the detected efferent response.

19. The method of claim 18, wherein detecting the efferent response comprises detecting at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

20. A system comprising:

a sensing module that generates a signal indicative of a physiological parameter of a patient;

a medical device that delivers peripheral nerve field stimulation to a region of a body of the patient in which the patient experiences pain via at least one electrode implanted in the region; and

a processor that receives the signal from the sensing module and controls the delivery of the peripheral nerve field stimulation by the medical device based on the signal, wherein the signal indicates a response of the patient to the peripheral nerve field stimulation.

21. The system of claim 20, wherein the physiological parameter comprises at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

22. The system of claim 20, wherein the medical device includes the sensing module.

23. The system of claim 20, wherein the sensing module is physically separate from the medical device.

24. The system of claim 20, wherein the signal indicates an efferent response of the patient to the peripheral nerve field stimulation.

25. The system of claim 20, wherein the medical device delivers peripheral nerve field stimulation according to a therapy program, and the processor controls the delivery of peripheral nerve field stimulation by automatically modifying the therapy program.

26. The system of claim 20, wherein the processor controls the delivery of peripheral nerve field stimulation by at least one of deactivating or initiating delivery of peripheral nerve field stimulation to the patient by the medical device.

27. The system of claim 20, wherein the sensing module comprises a first sensing module that generates a first signal that indicates a response of the patient to the peripheral nerve field stimulation, the system further comprising a second sensing module that generates a second signal indicative of the physiological parameter of the patient, wherein the processor compares a first characteristic of the first signal to a second characteristic of the second signal, and controls the delivery of the peripheral nerve field stimulation based on the comparison of the first and second characteristics.

28. The system of claim 27, wherein the second sensing module is positioned to generate the second signal indicative of an activity of the physiological parameter of the patient outside of the region of the body in which the patient experiences pain.

29. The system of claim 27, w herein the second signal does not indicate any response of the patient to the peripheral nerve field stimulation.

30. The system of claim 27, wherein the processor determines the first characteristic and the second characteristic, the first and second characteristics comprising at least one of an amplitude value, an energy level within a frequency band of the respective first or second signals or a pattern in a waveform of the respective first or second signals.

31. The system of claim 20, wherein the signal comprises a first signal, wherein the processor receives a second signal indicative of a second physiological parameter of the patient, the second signal indicating the response of the patient to the peripheral nerve field stimulation, and wherein the processor controls the delivery of the peripheral nerve field stimulation based on the first and second signals.

32. A system comprising:

means for delivering peripheral nerve field stimulation to a region of a body of a patient in which the patient experiences pain via at least one electrode implanted in the region;

means for receiving a signal indicative of a physiological parameter of the patient, wherein the signal indicates a response of the patient to the peripheral nerve field stimulation; and

means for controlling the delivery of the peripheral nerve field stimulation based on the physiological signal.

33. The system of claim 32, further comprising means for generating the signal, wherein the means for generating the signal generates the signal indicative of at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

34. The system of claim 32, further comprising:

means for receiving a second signal indicative of the physiological parameter of the patient; and

means for comparing a first characteristic of the first signal to a second characteristic of the second signal, wherein controlling the delivery of the peripheral nerve field stimulation comprises controlling the delivery of the peripheral nerve field stimulation based on the comparison of the first and second characteristics.

35. A method comprising:

receiving a signal indicative of a physiological parameter of a patient;

determining a patient pain state based on the signal; and

based on the patient pain state, controlling the delivery of peripheral nerve field stimulation to a region of a body of the patient in which the patient experiences pain via at least one electrode implanted in the region.

36. The method of claim 35, wherein controlling the delivery of the peripheral nerve field stimulation comprises initiating the delivery of the peripheral nerve field stimulation.

37. The method of claim 35, further comprising, prior to determining the patient pain state, delivering peripheral nerve field stimulation to the region of the body of the patient in which the patient experiences pain via the at least one electrode implanted in the region, wherein controlling the delivery of the peripheral nerve field stimulation comprises deactivating the delivery of the peripheral nerve field stimulation.

38. The method of claim 35, further comprising, prior to determining the patient pain state, delivering peripheral nerve field stimulation to the region of the body of the patient in which the patient experiences pain via the at least one electrode implanted in the region, wherein controlling the delivery of the peripheral nerve field stimulation comprises continuing the delivery of the peripheral nerve field stimulation.

39. The method of claim 35, wherein controlling the delivery of the peripheral nerve field stimulation comprises modifying a therapy program based on the patient pain state.

40. The method of claim 35, wherein controlling the delivery of the peripheral nerve field stimulation comprises selecting a therapy program based on the patient pain state.

41. The method of claim 35, further comprising:

receiving patient input indicating the patient pain state; and

associating the patient pain state with a characteristic of the signal, wherein controlling the delivery of the peripheral nerve field stimulation comprises detecting the characteristic of the signal.

42. The method of claim 35, wherein determining the patient pain state comprises at least one of comparing a peak amplitude of the signal to a threshold amplitude, comparing an average amplitude of the signal to the threshold amplitude, comparing a median amplitude of the signal to the threshold amplitude, comparing a trend in a waveform of the signal over time to a template, comparing a power level within one or more frequency bands of the signal to a threshold power level or comparing a ratio of power levels in two or more frequency bands of the signal to a threshold power level ratio

43. The method of claim 35, wherein the physiological parameter comprises at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

44. A system comprising:

a sensing module that generates a signal indicative of a physiological parameter of a patient;

a medical device that delivers peripheral nerve field stimulation to a region of a body of the patient in which the patient experiences pain via at least one electrode implanted in the region; and

a processor that receives the signal from the sensing module, determines a patient pain state based on the signal, and controls the medical device to deliver the peripheral nerve field stimulation to the patient based on the determined pain state.

45. The system of claim 44, wherein the sensing module generates a signal indicative of at least one of a heart rate, respiratory rate, electrodermal activity, muscle activity, blood flow rate, sweat gland activity, pilomotor reflex or thermal activity of the patient.

46. The system of claim 44, wherein the processor initiates the delivery of the peripheral nerve field stimulation based on the determined pain state.

47. The system of claim 44, wherein the medical device delivers peripheral nerve field stimulation to the region of the body of the patient during a stimulation period, wherein the processor determines the patient pain state after the stimulation period.

48. The system of claim 44, wherein the processor deactivates the delivery of the peripheral nerve field stimulation based on the determined pain state.

49. The system of claim 44, wherein the processor modifies a therapy program based on the patient pain state.

50. The system of claim 44, further comprising a memory that stores a plurality of therapy programs and information associating at least two of the therapy programs with different patient pain states, wherein the processor selects at least one of the plurality of therapy programs stored in the memory based on the patient pain state.

51. The system of claim 44, wherein the processor receives patient input indicating the patient pain state and associates the patient pain state with a characteristic of the signal.

52. The system of claim 44, wherein the processor determines the patient pain state by at least one of comparing a peak amplitude of the signal to a threshold amplitude, comparing an average amplitude of the signal to the threshold amplitude, comparing a median amplitude of the signal to the threshold amplitude, comparing a trend in a waveform of the signal over time to a template, comparing a power level within one or more frequency bands of the signal to a threshold power level or comparing a ratio of power levels in two or more frequency bands of the signal to a threshold power level ratio.

53. A system comprising:

means for receiving a signal indicative of a physiological parameter of a patient;

means for determining a patient pain state based on the signal; and

means for controlling delivery of peripheral nerve field stimulation to a region of a body of the patient in which the patient experiences pain based on the patient pain state, wherein the peripheral nerve field stimulation is delivered via at least one electrode implanted in the region.

54. The system of claim 53, further comprising means for receiving patient input indicating the patient pain state and means for associating the patient pain state with a characteristic of the signal, wherein the means for controlling the delivery of peripheral nerve field stimulation comprises means for detecting the characteristic of the signal.