Systems and Methods for Identifying a Contra-ictal Condition in a Subject

• US 20080183096A1
• Filed: 01/25/2008
• Published: 07/31/2008
• Est. Priority Date: 01/25/2007
• Status: Active Grant

• Current Assignee: Cyberonics, Inc
• Original Assignee: Cyberonics, Inc
• Inventors: Snyder, David, Leyde, Kent W., Harris, John F.
• Granted Patent: US 9,898,656 B2
• Time in Patent Office: Days
• US Class Current: 600/545
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/372 Analysis of electroencephalograms
• 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: G06F 2218/00 Aspects of pattern recognition specially adapted for signal processing
• CPC Class Codes: G16B 40/00 ICT specially adapted for biostatistics; ICT specially adapted for bioinformatics-related machine learning or data mining, e.g. knowledge discovery or pattern finding
• CPC Class Codes: G16B 40/30 Unsupervised data analysis
• CPC Class Codes: G16H 40/63 for local operation
• CPC Class Codes: G16H 40/67 for remote operation
• CPC Class Codes: G16H 50/20 for computer-aided diagnosis, e.g. based on medical expert systems
• CPC Class Codes: G16H 50/70 for mining of medical data, e.g. analysing previous cases of other patients

Abstract

The invention provides a method of monitoring a subject'"'"'s neurological condition. In some embodiments, the method includes the steps of analyzing a physiological signal (such as an EEG) from a subject to determine if the subject is in a contra-ictal condition; and if the subject is in a contra-ictal condition, providing an indication (e.g., to the subject and/or to a caregiver) that the subject is in the contra-ictal condition, such as by activating a green light or other visible output. In some embodiments, if the subject is in a pro-ictal condition, the method includes the step of providing an indication (such as a red light) that the subject is in the pro-ictal condition. The invention also provides neurological system monitors.

Claims

1. A method for identifying a contra-ictal condition for a subject, the method comprising:

obtaining a physiological signal dataset from the subject;

generating an N-dimensional feature vector for different time points of the physiological signal dataset;

identifying a grouping of feature vectors or a region of an N-dimensional feature space that is substantially free from ictal activity and is separated in time from subsequent ictal activity by a computed or predetermined time period; and

using the grouping of feature vectors or region of the N-dimensional feature space to identify a contra-ictal condition of the subject.

2. The method of claim 1 wherein the ictal activity comprises a seizure.

3. The method of claim 1 wherein the ictal activity comprises pro-ictal activity.

4. The method of claim 1 wherein the ictal activity comprises a seizure and pro-ictal activity.

5. The method of claim 1 further comprising storing the identified grouping of feature vectors or a mathematical representation of the identified grouping of feature vectors in memory.

6. The method of claim 1 further comprising customizing a contra-ictal algorithm for the subject based on the N-dimensional feature vector and disposing the contra-ictal algorithm in a physiological signal monitoring device.

7. A method of developing a physiological signal monitoring algorithm, the method comprising:

obtaining a physiological signal from a subject;

identifying ictal activity in the physiological signal;

extracting N features from the physiological signal;

generating a feature vector of the extracted N features for time points of the physiological signal;

identifying a grouping of points in a feature space that is free from ictal activity and is separated in time from the ictal activity by a predetermined or computed time period,

wherein the identified grouping of points is a state for the subject in which the subject is unlikely to have an ictal event within the predetermined or computed time period;

training the algorithm on the identified grouping of grouping of points;

storing the algorithm in a patient monitoring device; and

using the algorithm to identify a contra-ictal condition of the subject.

8. The method of claim 7 wherein the ictal activity comprises a seizure.

9. The method of claim 7 wherein the ictal activity comprises pro-ictal activity.

10. The method of claim 7 wherein the ictal activity comprises a seizure and pro-ictal activity.

11. The method of claim 7 further comprising storing the identified grouping of feature vectors or a mathematical representation of the identified grouping of feature vectors in memory.

12. A method of monitoring a subject'"'"'s neurological condition, the method comprising:

analyzing a physiological signal from a subject to determine if the subject is in a contra-ictal condition; and

if the subject is in a contra-ictal condition, providing an indication that the subject is in the contra-ictal condition.

13. The method of claim 12 wherein the indication is provided to the subject.

14. The method of claim 12 wherein the indication is provided to a caregiver.

15. The method of claim 12 further comprising providing an input to a closed loop therapeutic system adapted to minimize and/or prevent the occurrence of a seizure.

16. The method of claim 12 wherein the indication comprises a plurality of outputs, and wherein the predetermined time period comprises a plurality of predetermined time periods, and wherein providing the indication comprises providing an output that is indicative of one of the plurality of predetermined time periods.

17. The method of claim 12 wherein the indication comprises a green light.

18. The method of claim 12 wherein the indication comprises a visible output.

19. The method of claim 12 wherein the indication is the absence of an output.

20. The method of claim 12 further comprising, if the subject is in a pro-ictal condition, providing an indication that the subject is in the pro-ictal condition.

21. The method of claim 20 wherein the indication that the subject is in the pro-ictal condition comprises a red light.

22. The method of claim 20 further comprising, if the subject is not in a contra-ictal condition and not in a pro-ictal condition, providing an indication that the subject is not in either contra-ictal condition or a pro-ictal condition.

23. The method of claim 22 wherein the indication that the subject is not in either contra-ictal condition or a pro-ictal condition comprises a yellow light.

24. The method of claim 12 wherein analyzing the physiological signal comprises providing at least a portion of the physiological signal as an input to a classifier.

25. The method of claim 12 wherein analyzing the physiological signal further comprises extracting a feature vector from the physiological signal and providing the extracted feature vector as an input to a classifier.

26. The method of claim 12 wherein analyzing the physiological signal further comprises extracting N features from the physiological signal;

generating N dimensional feature vector of the extracted N features for time points of the physiological signal; and

determining if the N-dimensional feature vector is within a contra-ictal region in the N-dimensional space.

27. A subject advisory system comprising:

a processing assembly configured and programmed to process a data signal obtained from a subject to determine if the subject is in a contra-ictal condition; and

an indication assembly adapted to provide an indication that the subject is in the contra-ictal condition.

28. The subject advisory system of claim 27 wherein the processing assembly is adapted to be implanted within a subject.

29. The subject advisory system of claim 27 wherein part of the processing assembly is adapted to be implanted in a subject and part of the processing assembly is adapted to be external to the subject.

30. The subject advisory system of claim 27 wherein the indication assembly provides a substantially continuous output that indicates the subject'"'"'s condition.

31. The subject advisory system of claim 27 further comprising an implanted communication unit that is in communication with an electrode that samples a physiological signal from the subject,

wherein the data signal is indicative of the physiological signal and is substantially continuously transmitted substantially in real-time from the implanted communication unit to the processing assembly.

32. The subject advisory system of claim 31 wherein the implanted communication unit is in wireless communication with the processing assembly.

33. The subject advisory system of claim 27 wherein the contra-ictal condition comprises a condition in which the subject is at a low susceptibility to having a seizure within a predetermined time period.

34. The subject advisory system of claim 27 wherein the data signal comprises an extracted feature from a physiological signal from the subject.

35. The subject advisory system of claim 27 wherein the indication assembly comprises a green light.

36. A seizure advisory system comprising:

an electrode configured to sample an EEG signal from a subject;

an implanted communication unit coupled to the electrode, the implanted communication unit configured to transmit a wireless signal from the subject'"'"'s body; and

a subject advisory device that is external to the subject'"'"'s body, the subject advisory device comprising;

a processing assembly that processes the wireless signal to determine if the subject is in a contra-ictal condition; and

a user interface that provides an output to the subject that indicates that the subject is in the contra-ictal condition.

37. The seizure advisory system of claim 36 wherein the subject advisory device comprises a memory for storing the wireless signal.

38. A method of monitoring a subject'"'"'s neurological condition, the method comprising:

analyzing a physiological signal from the subject; and

providing an indication when the subject is highly unlikely to enter an ictal state for a predetermined period of time.

39. The method of claim 38 wherein the providing step comprises providing an indication when the subject is highly unlikely to have a seizure.

40. The method of claim 38 wherein the providing step comprises providing an indication when the subject is highly unlikely to enter a pro-ictal state.

41. The method of claim 38 wherein the providing step comprises providing an indication when the subject is highly unlikely to have a seizure or to enter a pro-ictal state.

42. The method of claim 38 wherein the period of time is greater than 10 minutes.

43. The method of claim 38 wherein the period of time is greater than 90 minutes.

44. The method of claim 38 wherein the indication comprises a green light.

45. The method of claim 38 further comprising providing an indication when the subject has a high susceptibility of entering an ictal state.

46. The method of claim 45 wherein the indication when the subject has a high susceptibility of entering an ictal state comprises a red light.

47. The method of claim 38 further comprising providing an indication when the subject is not highly unlikely to enter into an ictal state and does not have a high susceptibility of entering an ictal state.

48. The method of claim 47 wherein the indication when the subject is not highly unlikely to enter into an ictal state and does not have a high susceptibility of entering an ictal state comprises a yellow light.

49. A method of monitoring a subject'"'"'s neurological condition, the method comprising:

analyzing a physiological signal from a subject to determine the subject'"'"'s neurological state; and

based on the state determined in the analyzing step, providing an input to a closed loop therapeutic system adapted to alter the neurological state.

50. A user interface for a seizure advisory system, the user interface comprising:

a first indicator that indicates when the subject is in a contra-ictal condition;

a second indicator that indicates when the subject is in a pro-ictal condition; and

a processor that is configured to activate or deactivate the first and second indicator depending on the subject'"'"'s estimated condition.

51. The user interface of claim 50 wherein the first indicator comprises a green light and the second indicator comprises a red light.

52. The user interface of claim 50 further comprising a third indicator that indicates when the subject is not in the contra-ictal condition or the pro-ictal condition.

53. The user interface of claim 52 wherein the first indicator comprises a green light, the second indicator comprises a red light, and the third indicator comprises a yellow light.

54. The user interface of claim 50 wherein the first indicator and second indicator are discrete indicators on the user interface.

55. A user interface for a seizure advisory system, the user interface comprising:

an indicator that indicates when the subject is in a contra-ictal condition and a pro-ictal condition;

a processor that is configured to activate or deactivate the indicator based on the subject'"'"'s estimated condition.

56. A user interface for a seizure advisory system, the user interface comprising:

a first indicator that indicates when the subject is unlikely to transition to a pro-ictal condition within a period of time;

a second indicator that indicates when the subject is in a pro-ictal condition; and

a processor that is configured to activate or deactivate the first and second indicator depending on the subject'"'"'s estimated condition.

57. The user interface of claim 56 wherein the first indicator also indicates when the subject is unlikely to transition to an ictal condition within a period of time.

58. A user interface for a seizure advisory system, the user interface comprising:

a first indicator that indicates when the subject is unlikely to transition to an ictal condition within a period of time;

a second indicator that indicates when the subject is in a pro-ictal condition; and

a processor that is configured to activate or deactivate the first and second indicator depending on the subject'"'"'s estimated condition.