SYSTEM AND METHOD FOR MONITORING OR TREATING NERVOUS SYSTEM DISORDERS

• US 20070239054A1
• Filed: 04/27/2007
• Published: 10/11/2007
• Est. Priority Date: 12/17/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Thompson, David, Giftakis, Jonathon, Graves, Nina
• Granted Patent: US 8,485,979 B2
• Time in Patent Office: Days
• US Class Current: 600/513
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/29 for permanent or long-term implantation
• CPC Class Codes: A61B 5/293 Invasive
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/365 controlled by a physiological parameter, e.g. heart potential evoked response A61N1/371

Abstract

An implantable neurostimulator device for implantation in a head of a patient includes a housing adapted to be implanted beneath a patient'"'"'s scalp, and a cardiac monitoring element, a brain monitoring element, and a processor. The processor is configured to receive a cardiac signal from the cardiac monitoring element, identify cardiac events in the cardiac signal, receive a brain signal from the brain monitoring element, identify neurological events in the brain signal, and indicate a relationship between the neurological events and the cardiac events.

Claims

1. An implantable device for implantation in a head of a patient, the device comprising:

a biocompatible housing adapted to be implanted beneath a patient'"'"'s scalp;

a cardiac monitoring element at least partially housed within the housing, the cardiac monitoring element adapted to sense cardiac activity to generate a cardiac signal;

a brain monitoring element operatively coupled to the housing, the brain monitoring element adapted to sense brain activity to generate a brain signal; and

a processor at least partially housed within the housing, the processor configured to

(a) receive the cardiac signal from the cardiac monitoring element,

(b) identify one or more cardiac events in the cardiac signal,

(c) receive the brain signal from the brain monitoring element,

(d) identify one or more neurological events in the brain signal, and

(e) indicate a relationship between the neurological events and the cardiac events.

2. The device of claim 1 wherein the processor is configured to identify cardiac events and neurological events based upon input received by the processor via a user interface.

3. The device of claim 1 wherein the processor is configured to identify cardiac events in the cardiac signal based on a cardiac event detection algorithm, and wherein the processor is configured to identify neurological events in the brain signal based upon a neurological event detection algorithm.

4. The device of claim 1 wherein the cardiac monitoring element generates the cardiac signal without using a lead implanted near a heart of the patient.

5. The device of claim 1 wherein the housing comprises an overmold that at least partially encloses the cardiac monitoring element, the housing being adapted to be implanted between a cranium and a scalp of the patient.

6. The device of claim 1 wherein the housing is adapted to be fixed to a cranial bone.

7. The device of claim 1 wherein the housing is adapted to be at least partially disposed in a recess formed in a cranial bone.

8. The device of claim 1 wherein the brain monitoring element comprises a lead for sensing the brain activity and communicating the brain signal to the processor.

9. The device of claim 1 wherein the cardiac monitoring element is an acoustic sensor coupled to the housing to sense cardiac activity.

10. The device of claim 9 wherein the acoustic sensor senses heart sounds to generate the cardiac signal.

11. The device of claim 10 wherein the cardiac signal generated is a function of an intensity of the sensed heart sounds.

12. The device of claim 11 wherein detection of the one or more cardiac events occurs when the intensity of the sensed heart sounds changes by a threshold amount.

13. The device of claim 10 wherein the cardiac signal generated is a function of the timing of heart sounds.

14. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a heart rate change greater than a threshold amount.

15. The device of claim 14 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a heart rate that changes by more than a threshold amount within a predefined time window.

16. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a heart rate exceeding a threshold rate.

17. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a measured heart rate variability that falls outside of a defined range.

18. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a measured QT interval variability that falls outside of a defined range.

19. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a rate-corrected QT interval (“

QT_C”

) that falls outside of a defined range.

20. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a sinus arrest episode.

21. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a syncope episode.

22. The device of claim 21 wherein the syncope episode includes a sudden drop in heart rate.

23. The device of claim 13 wherein detection of the one or more cardiac events occurs when the timing of heart sounds indicates a detected arrhythmia.

24. The device of claim 10 wherein the heart sounds sensed by the acoustic sensor are applied to a low-pass filter prior to generating the cardiac signal.

25. The device of claim 24 wherein the low-pass filter limits signals to less than 4 Hz.

26. The device of claim 1 wherein the cardiac monitoring element is a blood pressure sensor coupled to the housing to sense cardiac activity.

27. The device of claim 26 wherein detection of the one or more cardiac events occurs when the sensed blood pressure changes by more than a threshold amount.

28. The device of claim 27 wherein detection of the one or more cardiac events occurs when the sensed blood pressure changes by more than a threshold amount within a predefined time window.

29. The device of claim 26 wherein detection of the one or more cardiac events occurs when the sensed blood pressure exceeds a threshold level.

30. The device of claim 26 wherein the blood pressure sensor employs a capacitive sensor to measure blood pressure.

31. The device of claim 26 wherein the blood pressure sensor employs a strain gauge sensor to measure blood pressure.

32. The device of claim 1 wherein the cardiac monitoring element is an oxygen saturation sensor coupled to the housing to sense cardiac activity.

33. The device of claim 32 wherein detection of the one or more cardiac events occurs when the oxygen saturation level changes by more than a threshold amount.

34. The device of claim 33 wherein detection of the one or more cardiac events occurs when the oxygen saturation level changes by more than a threshold amount within a predefined time window.

35. The device of claim 32 wherein detection of the one or more cardiac events occurs when the oxygen saturation level exceeds a threshold level.

36. The device of claim 32 wherein the oxygen saturation sensor employs a reflectance oximeter to measure oxygen saturation level.

37. The device of claim 1 wherein the processor is configured to perform the following:

(a) for each of the one or more identified neurological events, determine whether the neurological event is within a specified time period of one of the one or more identified cardiac events; and

(b) for each of the one or more identified cardiac events, determine whether the cardiac event is within a specified time period of one of the one or more identified neurological events.

38. The device of claim 37 wherein the processor is configured to determine the number of neurological events that are within the specified time period of one of the one or more identified cardiac events.

39. The device of claim 37 wherein the processor is configured to determine the number of neurological events that are not within the specified time period of one of the one or more identified cardiac events.

40. The device of claim 37 wherein the processor is configured to determine the number of cardiac events that are not within the specified time period of one of the one or more identified neurological events.

41. The device of claim 37 wherein, for the neurological events that are within the specified time period of one of the one or more identified cardiac events, the processor is configured to determine the temporal order of the neurological event and the cardiac event.

42. The device of claim 41 wherein determining the temporal order comprises determining whether the cardiac event precedes the corresponding neurological event.

43. The device of claim 42 wherein the processor is configured to enable a cardiac event detection algorithm to detect neurological events when a number of cardiac events that precede the corresponding neurological events exceeds a predetermined fraction of the neurological events.

44. The device of claim 41 wherein the processor is configured to determine the amount of time between the neurological event and the cardiac event.

45. The device of claim 44 wherein determining the amount of time between the neurological event and the cardiac event comprises comparing a first reference point indicative of the temporal location of the neurological event to a second reference point indicative of the temporal location of the cardiac event.

46. The device of claim 45 wherein the first reference point is a starting point of the neurological event, and the second reference point is a starting point of the cardiac event.

47. The device of claim 45 wherein the first reference point is between a starting point and an ending point of the neurological event, and the second reference point is between a starting point and an ending point of the cardiac event.

48. The device of claim 37 wherein the specified time period is programmable.

49. The device of claim 1 wherein the processor is configured to indicate a relationship between the neurological events and the cardiac events by performing the following:

(a) categorizing the neurological event as cardiac matched when there is a cardiac event in close temporal relationship with the neurological event; and

(b) computing a rate of concordance between the neurological events and the cardiac events based on a number of cardiac matched neurological events.

50. The device of claim 49 wherein computing the rate of concordance comprises dividing the number of cardiac matched neurological events by a total number of neurological events.

51. The device of claim 50 wherein the processor is configured to enable a cardiac event detection algorithm to detect neurological events when the rate of concordance exceeds a predetermined value.

52. The device of claim 1 wherein the processor is configured to enable a cardiac event detection algorithm to detect neurological events based on the relationship between the neurological events and the cardiac events.

53. The device of claim 52 wherein the processor is configured to enable the cardiac event detection algorithm to detect neurological events when a rate of concordance between the neurological events and the cardiac events exceeds a predetermined value.

54. The device of claim 52 further comprising a therapy delivery module adapted to deliver a therapeutic output to the patient to treat the neurological event when the cardiac event detection algorithm detects a cardiac event.

55. The device of claim 54 wherein the therapeutic output is delivered to a brain of the patient.

56. The device of claim 54 wherein the therapeutic output delivered by the therapy module includes electrical stimulation.

57. The device of claim 56 wherein the therapy module is adapted to be coupled to a stimulation electrode for delivering electrical stimulation to a brain of the patient.

58. The device of claim 57 wherein the processor is adapted to change the therapeutic output delivered by the therapy module based on the brain signal.

59. The device of claim 58 wherein a single lead carries both the stimulation electrode and the brain monitoring element.

60. The device of claim 59 wherein a single electrode functions as both the stimulation electrode and the brain monitoring element.

61. The device of claim 57 wherein the coupling between the therapy module and the stimulation electrode is selected from the group consisting of conductive coupling, magnetic coupling, and radio frequency coupling.

62. The device of claim 54 wherein the therapeutic output delivered by the therapy module includes drug delivery.

63. The device of claim 62 wherein the therapy module is adapted to be coupled to a drug delivery pump for delivering drug therapy to the brain of the patient.

64. The device of claim 63 wherein the processor is adapted to change the therapeutic output delivered by the therapy module based on the sensed brain signals.

65. An implantable medical device for implantation in a head of a patient, the device comprising:

a biocompatible housing adapted to be implanted beneath a patient'"'"'s scalp;

a brain monitoring element, the brain monitoring element adapted to sense brain activity to generate a brain signal;

a processor at least partially housed within the housing, the processor being adapted to

(a) receive a cardiac signal from a remote cardiac monitoring element and detect one or more cardiac events in the cardiac signal,

(b) receive the brain signal from the brain monitoring element and detect one or more neurological events in the brain signal, and

(c) indicate a relationship between the one or more neurological events and the one or more cardiac events.

66. The device of claim 65 wherein the remote cardiac monitoring element is adapted to sense cardiac activity and generate and transmit the cardiac signal to the processor.

67. The device of claim 65 wherein the housing comprises an overmold that at least partially encloses the processor, the housing being adapted to be implanted between a cranium and a scalp of the patient.

68. The device of claim 66 wherein the remote cardiac monitoring element is an implantable loop recorder for sensing electrical cardiac activity.

69. The device of claim 68 wherein the processor is adapted to receive analog cardiac signals from the remote cardiac monitoring element.

70. The device of claim 68 wherein the processor is adapted to receive digital event information from the remote cardiac monitoring element.

71. The device of claim 65 wherein the remote cardiac monitoring element is a cardiac vest worn by the patient, the vest being adapted for sensing electrical cardiac activity.

72. The device of claim 65 wherein the remote cardiac monitoring element is a patch worn by the patient, the patch being adapted for sensing electrical cardiac activity.

73. The device of claim 65 wherein the remote cardiac monitoring element is an acoustic sensor for sensing heart sounds.

74. The device of claim 65 wherein the remote cardiac monitoring element is a blood pressure sensor for sensing blood pressure levels in the patient.

75. The device of claim 65 wherein the remote cardiac monitoring element is an oxygen saturation sensor for sensing oxygen saturation levels in the patient.

76. The device of claim 65 wherein the processor is configured to enable a cardiac event detection algorithm to detect neurological events based on the relationship between the neurological events and the cardiac events.

77. The device of claim 76 further comprising a therapy module at least partially housed within the housing, the therapy module adapted to deliver a therapeutic output to the patient when the cardiac event detection algorithm detects a neurological event.

78. The device of claim 77 wherein the therapy module is electrically coupled to a lead for delivering electrical stimulation therapy to the brain of the patient.

79. The device of claim 78 wherein the lead for delivering electrical stimulation therapy to the brain of the patient also carries the brain monitoring element, and wherein the processor is adapted to change the electrical stimulation therapy based on the brain signals.

80. An implantable system comprising:

a biocompatible housing adapted to be implanted beneath a patient'"'"'s scalp;

a cardiac monitoring element adapted to sense cardiac activity and generate a cardiac signal;

a brain monitoring element adapted to sense brain activity and generate a brain signal;

a processor at least partially housed within the housing, the processor being configured to

(a) receive the cardiac signal from the cardiac monitoring element and detect one or more cardiac events in the cardiac signal,

(b) receive the brain signal from the brain monitoring element and detect one or more neurological events in the brain signal, and

(c) indicate a relationship between the neurological events and the cardiac events.

81. The system of claim 80 wherein the processor is further configured to enable a cardiac event detection algorithm to detect neurological events when the relationship between the neurological events and the cardiac events indicates a rate of concordance between the neurological events and the cardiac events that exceeds a threshold value.

82. The system of claim 81 wherein the rate of concordance is determined based on a number of the neurological events that are temporally related to one of the cardiac events.

83. The system of claim 81 further comprising a therapy module at least partially supported by the housing, the therapy module adapted to deliver a therapeutic output to the patient when the cardiac event detection algorithm detects neurological events.

84. The system of claim 83 further comprising an electrode operatively coupled to the therapy module, the electrode being adapted to deliver electrical stimulation therapy to a brain of the patient in response to the cardiac event detection algorithm detecting one or more neurological events.

85. The system of claim 84 wherein the electrode for delivering electrical stimulation therapy forms at least a portion of the brain monitoring element.

86. The system of claim 85 wherein the processor is adapted to change the therapeutic output delivered by the therapy module based on the brain signals.

87. The system of claim 86 wherein the therapeutic output delivered by the therapy module is dependent upon the brain signals for a period following a detected cardiac event.