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

• US 20080234598A1
• Filed: 03/21/2008
• Published: 09/25/2008
• Est. Priority Date: 03/21/2007
• Status: Active Grant

• Current Assignee: Cyberonics, Inc
• Original Assignee: NeuroVista Corporation
• Inventors: Snyder, David, Leyde, Kent W., Harris, John F.
• Granted Patent: US 8,036,736 B2
• Time in Patent Office: Days
• US Class Current: 600/545
• CPC Class Codes: A61B 2560/0219 of externally powered implanted units
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• 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 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/08 Detecting, measuring or recording devices for evaluating the respiratory organs A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/374 Detecting the frequency distribution of signals, e.g. detecting delta, theta, alpha, beta or gamma waves
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/7232 involving compression of the physiological signal, e.g. to extend the signal recording period

Abstract

Systems and methods of monitoring a subject'"'"'s neurological condition are provided. 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. The systems and methods may utilize a minimally invasive, leadless device to monitor the subject'"'"'s condition. 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.

Claims

1. A minimally invasive seizure advisory system comprising:

a plurality of implantable devices, each implantable device configured to sample an EEG signal from a subject and 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 signals from each of the plurality of implantable devices 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.

2. The seizure advisory system of claim 1 wherein the subject advisory device comprises a memory for storing the wireless signal.

3. The seizure advisory system of claim 1 wherein the contra-ictal condition is a neurological state in which the subject is unlikely to transition into an ictal condition within a time period.

4. The seizure advisory system of claim 3 wherein the time period is a predetermined time period.

5. The seizure advisory system of claim 1 wherein the output to the subject is a green light.

6. The seizure advisory system of claim 1 wherein the output to the subject is an audible output, a tactile output, a visible output, or a combination thereof.

7. The seizure advisory system of claim 1 wherein each of the implantable devices is adapted to be implanted between the subject'"'"'s skull and scalp.

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

implanting a device between a subject'"'"'s skull and scalp;

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

if the subject is in a contra-ictal condition, providing an output to the subject that is indicative of the subject being in the contra-ictal condition.

9. The method of claim 8 wherein the contra-ictal condition is a neurological state in which the subject is unlikely to transition into an ictal condition within a time period.

10. The method of claim 9 wherein the time period is a predetermined time period.

11. The method of claim 8 wherein the physiological signal is an EEG signal.

12. The method of claim 8 wherein the output to the subject is a green light.

13. The method of claim 8 wherein the output to the subject is an audible output, a tactile output, a visible output, or a combination thereof.

14. The method of claim 8 wherein the output is a combination of at least two of an audible output, a visible output, and a tactile output.

15. The method of claim 8 wherein analyzing the physiological signal comprises:

extracting N features from the physiological signal;

generating a 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 cluster or region in the N-dimensional space.

16. The method of claim 8 wherein analyzing the physiological signal comprises:

extracting N features from the physiological signal;

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

transforming the N-dimensional feature vector to an M-dimensional feature vector; and

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

17. A subject advisory system comprising:

an implantable device adapted to sample a physiological signal from a subject and transmit a wireless signal from a subject'"'"'s head;

a processing assembly that processes the wireless signal from the implantable device 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.

18. The subject advisory system of claim 17 wherein the user interface provides a substantially continuous output to the subject regarding their condition.

19. The subject advisory system of claim 17 wherein the wireless signal is indicative of the physiological signal and is substantially continuously transmitted substantially in real-time from the implanted minimally invasive leadless device to the processing assembly.

20. The subject advisory system of claim 17 wherein the implantable device is a minimally-invasive device.

21. The subject advisory system of claim 17 wherein the contra-ictal condition comprises a condition in which the subject is at a low susceptibility to having a seizure within a time period.

22. The subject advisory system of claim 17 wherein the wireless signal is a processed physiological signal.

23. The subject advisory system of claim 17 wherein the processing assembly and user interface are both part of a patient handheld device.

24. The subject advisory system of claim 17 wherein the wireless signal comprises a compressed EEG signal or an encrypted EEG signal.

25. The subject advisory system of claim 17 wherein the wireless signal comprises an extracted feature from a physiological signal from the subject.

26. The subject advisory system of claim 17 wherein the output to the subject that indicates that the subject is in the contra-ictal condition comprises a green light.

27. The subject advisory system of claim 17 wherein the output to the subject that indicates that the subject is in the contra-ictal condition comprises an audible output, a tactile output, a visual output on a display, or a combination thereof.

28. The subject advisory system of claim 17 wherein the implantable devices is adapted to be implanted between the subject'"'"'s skull and scalp.