SEIZURE DISORDER EVALUATION BASED ON INTRACRANIAL PRESSURE AND PATIENT MOTION

• US 20100121214A1
• Filed: 01/23/2009
• Published: 05/13/2010
• Est. Priority Date: 11/11/2008
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Herzog, Michele H., Werder, Jonathan C., Giftakis, Jonathon E., Miesel, Keith A., Graves, Nina M., Denison, Timothy J., Panken, Eric J.
• Application Number:
  US12/359,055
• Publication Number:
  US 20100121214A1
• Time in Patent Office: Days
• US Class Current: 600/544
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61N 1/0534 Electrodes for deep brain stimulation
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease

Abstract

Intracranial pressure of a patient may be monitored in order to evaluate a seizure disorder. In some examples, trends in the intracranial pressure over time may be monitored, e.g., to detect changes to the patient'"'"'s condition. In addition, in some examples, a seizure metric may be generated for a detected seizure based on sensed intracranial pressures. The seizure metric may indicate, for example, an average, median, or highest relative intracranial pressure value observed during a seizure, a percent change from a baseline value during the seizure, or the time for the intracranial pressure to return to a baseline state after the occurrence of a seizure. In addition to or instead of intracranial pressure, patient motion or posture may be monitored in order to assess the patient'"'"'s seizure disorder. For example, a seizure type or severity may be determined based on patient motion sensed during a seizure.

Claims

1. A method comprising:

sensing intracranial pressure of a patient;

detecting a seizure of the patient;

determining a seizure metric based on the intracranial pressure; and

storing the seizure metric in a memory.

2. The method of claim 1, wherein sensing intracranial pressure of a patient comprises sensing intracranial pressure of the patient with a pressure sensor implanted within a cranium of the patient.

3. The method of claim 1, wherein sensing intracranial pressure of a patient comprises sensing the intracranial pressure at a frequency of at least one of once per second, once per minute, once per hour or once per day.

4. The method of claim 1, wherein sensing intracranial pressure of a patient comprises sensing the intracranial pressure within a ventricle of a brain of the patient.

5. The method of claim 1, wherein the seizure metric comprises at least one of an average, median or highest intracranial pressure value during the seizure.

6. The method of claim 1, wherein the seizure metric comprises a percent change of the value of the intracranial pressure sensed during the seizure relative to a baseline value, a standard deviation of the intracranial pressure from the baseline value during the seizure, or a change in the intracranial pressure values over time during the seizure.

7. The method of claim 1, further comprising:

detecting an intracranial pressure value that is greater than a baseline value; and

detecting when the intracranial pressure value returns to the baseline value, wherein the seizure metric comprises a duration of time during which the intracranial pressure returned to the baseline value.

8. The method of claim 1, further comprising:

generating a seizure indication based on the detected seizure;

associating the seizure indication with an intracranial pressure value; and

storing the intracranial pressure value and the seizure indication in a memory.

9. The method of claim 1, further comprising:

determining whether a value of the intracranial pressure is greater than or equal to a first threshold value;

generating a first intracranial pressure category indication if the value of the intracranial pressure is greater than or equal to the first threshold value;

determining whether the value of the intracranial pressure is greater than or equal to a second threshold value if the value of the intracranial pressure is not greater than or equal to the first threshold value;

generating a second intracranial pressure category indication if the value of the intracranial pressure is greater than or equal to the second threshold value; and

generating a third intracranial pressure category indication if the value of the intracranial pressure is not greater than or equal to the second threshold value, wherein the seizure metric comprises at least one of the first, second or third intracranial pressure category indications.

10. The method of claim 9, wherein the first threshold value is greater than or equal to about 20 mmHg.

11. The method of claim 9, wherein the second threshold value is greater than or equal to about 15 mmHg.

12. The method of claim 9, wherein the seizure metric comprises a first seizure metric, the method further comprising:

monitoring patient motion; and

determining a second seizure metric based on the patient motion.

13. The method of claim 12, wherein the second seizure metric comprises at least one of an indication of a change in patient posture or an increase in patient motion after the detection of the seizure.

14. The method of claim 1, further comprising presenting a list of a plurality of detected seizures and respective seizure metrics to a user.

15. The method of claim 1, wherein detecting the seizure comprises detecting the seizure based on at least one of a bioelectrical brain signal of the patient, impedance of a brain of the patient, detected motion of the patient or patient input.

16. A system comprising:

a pressure sensor that senses intracranial pressure of a patient;

a memory; and

a processor that detects a seizure of the patient, determines a seizure metric based on the intracranial pressure, and stores the seizure metric in the memory.

17. The system of claim 16, further comprising a therapy delivery element that delivers therapy to the patient, wherein the therapy delivery element comprises the pressure sensor.

18. The system of claim 16, further comprising an implantable medical device that generates therapy that is delivered to the patient, wherein the pressure sensor is physically separate from the implantable medical device.

19. The system of claim 16, further comprising an implantable medical device that generates therapy that is delivered to the patient, wherein the implantable medical device comprises the processor.

20. The system of claim 16, further comprising a medical device programmer that comprises the processor.

21. The system of claim 16, further comprising a sensing module that senses a bioelectrical brain signal of the patient via two or more electrodes, wherein the processor detects the seizure based on the bioelectrical brain signal.

22. The system of claim 16, further comprising an impedance sensing module electrically connected to two or more electrodes, wherein the impedance sensing module measures an impedance of a brain of the patient via the two or more electrodes and the processor detects the seizure based on the impedance.

23. The system of claim 16, further comprising a motion sensor that generates a signal indicative of patient motion, wherein the processor detects the seizure based on the signal from the motion sensor.

24. The system of claim 16, further comprising a user interface that receives user input, wherein the processor detects the seizure based on the user input.

25. The system of claim 16, wherein the seizure metric comprises at least one of an average, median or highest intracranial pressure value during the seizure.

26. The system of claim 16, wherein the seizure metric comprises a percent change of the value of the intracranial pressure sensed during the seizure relative to a baseline value, a standard deviation of the intracranial pressure from the baseline value during the seizure, or a change in the intracranial pressure values over time during the seizure.

27. The system of claim 16, wherein the processor detects an intracranial pressure value that is greater than a baseline value after detecting the seizure, and detects when the intracranial pressure value returns to the baseline value after detecting the seizure, wherein the seizure metric comprises a duration of time during which the intracranial pressure returned to the baseline value.

28. The system of claim 16, wherein the processor determines whether a value of the intracranial pressure is greater than or equal to a first threshold value, generates a first intracranial pressure category indication if the value of the intracranial pressure is greater than or equal to the first threshold value, determines whether the value of the intracranial pressure is greater than or equal to a second threshold value if the value of the intracranial pressure is not greater than or equal to the first threshold value, generates a second intracranial pressure category indication if the value of the intracranial pressure is greater than or equal to the second threshold value, and generates a third seizure indication if the value of the intracranial pressure is not greater than or equal to the second threshold value, wherein the seizure metric comprises at least one of the first, second, or third intracranial pressure category indications.

29. The system of claim 16, wherein the seizure metric comprises a first seizure metric, the system further comprising a motion sensor that generates a signal indicative of patient motion or patient posture, wherein the processor monitors patient motion via the motion sensor and determines a second seizure metric based on the patient motion.

30. The system of claim 29, wherein the seizure metric comprises at least one of an indication of a change in patient posture or an increase in patient motion after the detection of the seizure.

31. The system of claim 29, further comprising a user interface, wherein the processor presents a list of a plurality of detected seizures and associated seizure metrics to a user via the user interface.

32. A system comprising:

means for sensing intracranial pressure of a patient;

means for detecting a seizure of the patient;

means for determining a seizure metric based on the intracranial pressure; and

means for storing the seizure metric in a memory.

33. A method comprising:

receiving a signal from a motion sensor, wherein the signal is indicative of motion of a patient;

detecting a seizure of the patient;

after detecting the seizure, determining a seizure metric based on the signal from the motion sensor; and

storing the seizure metric in a memory.

34. The method of claim 33, wherein the seizure metric comprises at least one of an indication of a change in patient posture or an increase in patient motion after the detection of the seizure.

35. The method of claim 33, wherein determining the seizure metric comprises correlating the signal from the motion sensor to a template, wherein the seizure metric indicates whether the signal substantially correlates to the template.

36. The method of claim 33, wherein determining the seizure metric comprises:

determining a change in patient motion over time based on the signal from the motion sensor, wherein the signal indicates patient motion during the seizure; and

comparing the change in patient motion over time to a threshold value, wherein the seizure metric indicates whether the change in patient motion over time was greater than or equal to the threshold value.

37. The method of claim 33, further comprising detecting a prone posture of the patient based on the signal from the motion sensor and generating a patient notification upon detecting the prone posture.

38. A system comprising:

a memory;

a motion sensor that that generates a signal indicative of patient motion or patient posture; and

a processor that receives the signal from the motion sensor, detects a seizure of the patient, and, after detecting the seizure, determines a seizure metric based on the signal from the motion sensor and stores the seizure metric in the memory.

39. The system of claim 38, further comprising a therapy delivery element that delivers therapy to the patient, wherein the therapy delivery element comprises the motion sensor.

40. The system of claim 38, further comprising an implantable medical device that generates therapy that is delivered to the patient, wherein the motion sensor is physically separate from the implantable medical device.

41. The system of claim 38, further comprising an implantable medical device that generates therapy that is delivered to the patient, wherein the implantable medical device comprises the motion sensor.

42. The system of claim 38, wherein the seizure metric comprises at least one of an indication of a change in patient posture or an increase in patient motion after the detection of the seizure.

43. The system of claim 38, wherein the processor determines the seizure metric by at least correlating the signal from the motion sensor to a template, wherein the seizure metric indicates whether the signal substantially correlates to the template.

44. The system of claim 43, wherein the signal comprises a first signal and the template defines a second signal indicative of a convulsive patient motion.

45. The system of claim 38, wherein the processor determines the seizure metric by at least determining a change in patient motion over time based on the signal from the motion sensor, wherein the signal indicates patient motion during the seizure, and comparing the change in patient motion over time to a threshold value, wherein the seizure metric indicates whether the change in patient motion over time was greater than or equal to the threshold value.

46. The system of claim 38, wherein the processor detects a prone posture of the patient based on the signal from the motion sensor and generates a patient notification upon detecting the prone posture.

47. A system comprising:

means for receiving a signal from a motion sensor, wherein the signal is indicative of motion of a patient;

means for detecting a seizure of the patient;

means for determining a seizure metric based on the signal from the motion sensor after detecting the seizure; and

means for storing the seizure metric in a memory.