SEIZURE DISORDER EVALUATION BASED ON INTRACRANIAL PRESSURE AND PATIENT MOTION

• US 20100121213A1
• Filed: 01/23/2009
• Published: 05/13/2010
• Est. Priority Date: 11/11/2008
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Werder, Jonathan C., Giftakis, Jonathon E., Miesel, Keith A., Graves, Nina M., Denison, Timothy J., Panken, Eric J., Herzog, Michele H.
• Granted Patent: US 10,369,353 B2
• 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:

delivering therapy to a patient to manage a seizure disorder;

sensing intracranial pressure of the patient;

determining a trend in the intracranial pressure over time; and

generating an intracranial pressure indication if a value of the intracranial pressure is greater than or equal to a threshold value.

2. The method of claim 1, further comprising determining a change in the seizure disorder based on the trend in the intracranial pressure over time.

3. 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.

4. 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.

5. 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.

6. The method of claim 1, wherein the threshold value comprises about 15 millimeters of mercury (mmHg) to about 20 mmHg.

7. The method of claim 1, wherein the intracranial pressure indication comprises a first intracranial pressure indication, and wherein determining the trend in the intracranial pressure over time comprises determining whether the intracranial pressure increases over time, the method further comprising generating a second intracranial pressure indication if the intracranial pressure increases over time.

8. The method of claim 1, wherein generating the intracranial pressure indication if the value of the intracranial pressure is greater than or equal to the threshold value comprises generating the intracranial pressure indication if at least one of a mean or median intracranial pressure value over a predetermined period of time is greater than or equal to the threshold value.

9. The method of claim 1, wherein generating the intracranial pressure indication if the value of the intracranial pressure is greater than or equal to the threshold value comprises generating the intracranial pressure indication if a current value of the intracranial pressure is greater than or equal to the threshold value.

10. The method of claim 1, further comprising generating at least one of an audible, visible or somatosensory notification if the value of the intracranial pressure is greater than or equal to the threshold value.

11. The method of claim 1, further comprising:

detecting a seizure of the patient;

determining a seizure metric based on the intracranial pressure; and

storing the seizure metric in a memory.

12. The method of claim 11, wherein the seizure metric comprises at least one of an average, median or highest intracranial pressure value during the seizure.

13. The method of claim 11, 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.

14. The method of claim 11, further comprising:

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

detecting 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.

15. The method of claim 11, wherein the threshold value comprises a first threshold value, the method further comprising:

after detecting the seizure, determining whether the intracranial pressure is greater than or equal to a second threshold value;

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

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

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

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

16. The method of claim 15, wherein the second threshold value is greater than the third intracranial pressure value.

17. The method of claim 11, wherein the seizure metric comprises a first seizure metric, the method further comprising:

monitoring patient motion;

determining a second seizure metric based on the patient motion.

18. The method of claim 17, wherein the second seizure metric indicates a change in patient posture after the detection of the seizure.

19. The method of claim 17, wherein the second seizure metric indicates an increase in patient motion after the detection of the seizure.

20. A system comprising:

an implantable medical device that delivers therapy to a patient to manage a seizure disorder;

a pressure sensor that senses intracranial pressure of the patient; and

a processor that determines a trend in the intracranial pressure over time and generates an intracranial pressure indication if a value of the intracranial pressure is greater than or equal to a threshold value.

21. The system of claim 20, wherein the processor detects a change in the seizure disorder based on the trend in the intracranial pressure over time.

22. The system of claim 20, further comprising a therapy delivery element that delivers therapy to the patient, wherein the therapy delivery element comprises the pressure sensor.

23. The system of claim 20, wherein the pressure sensor is physically separate from the implantable medical device.

24. The system of claim 20, wherein the threshold value comprises about 15 millimeters of mercury (mmHg) to about 20 mmHg.

25. The system of claim 20, wherein the intracranial pressure indication comprises a first intracranial pressure indication, and wherein the processor determines the trend in the intracranial pressure over time by at least determining whether the intracranial pressure increases over time, wherein the processor generates a second intracranial pressure indication if the intracranial pressure increases over time.

26. The system of claim 20, wherein the value of the intracranial pressure comprises at least one of a mean or median intracranial pressure value over a predetermined period of time.

27. The system of claim 20, wherein the processor generates a user notification if the value of the intracranial pressure is greater than or equal to the threshold value.

28. The system of claim 27, further comprising a user interface, wherein the notification comprises at least one of a visual, auditory or somatosensory alert that is transmitted to a user via the user interface.

29. The system of claim 27, further wherein the processor generates the user notification by causing the implantable medical device to vibrate or generate an audible sound.

30. The system of claim 20, further comprising a memory, wherein the processor detects a seizure of the patient, determines a seizure metric based on the intracranial pressure, and stores the seizure metric in the memory.

31. The system of claim 30, 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.

32. The system of claim 30, wherein the seizure metric comprises at least one of an average, median or highest intracranial pressure value during the seizure.

33. The system of claim 30, 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.

34. The system of claim 30, 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.

35. The system of claim 30, wherein the threshold value comprises a first threshold value, and, after detecting the seizure, the processor determines whether the intracranial pressure is greater than or equal to a second threshold value, generates a first intracranial pressure category indication if the intracranial pressure is greater than or equal to the second threshold value, determines whether the intracranial pressure is greater than or equal to a third threshold value if the intracranial pressure is not greater than or equal to the second threshold value, generates a second intracranial pressure category indication if the intracranial pressure is greater than or equal to the third threshold value, and generates a third intracranial pressure category indication if the intracranial pressure is not greater than or equal to the third threshold value, wherein the seizure metric comprises at least one of the first, second or third intracranial pressure category indications.

36. The system of claim 20, 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 seizure metric based on the patient motion.

37. The system of claim 36, wherein the seizure metric indicates a change in patient posture after the detection of the seizure.

38. The system of claim 36, wherein the seizure metric indicates an increase in patient motion after the detection of the seizure.

39. A system comprising:

means for delivering therapy to a patient to manage a seizure disorder;

means for sensing intracranial pressure of the patient;

means for determining a trend in the intracranial pressure over time; and

means for generating an intracranial pressure indication if a value of the intracranial pressure is greater than or equal to a threshold value.

40. The system of claim 39, further comprising:

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.

41. The system of claim 39, further comprising:

means for monitoring patient motion; and

means for determining a seizure metric based on the patient motion.