Dynamic cranial nerve stimulation based on brain state determination from cardiac data

• US 8,417,344 B2
• Filed: 10/24/2008
• Issued: 04/09/2013
• Est. Priority Date: 10/24/2008
• Status: Active Grant

• Current Assignee: Flint Hills Scientific, LLC, LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc, Flint Hills Scientific, LLC
• Inventors: Colborn, John C., Frei, Mark G., Osorio, Ivan
• Primary Examiner(s): MANUEL, GEORGE C
• Application Number:
  US12/258,019
• Publication Number:
  US 20100106217A1
• Time in Patent Office: 1,628 Days
• Field of Search: 607/45
• US Class Current: 607/45
• 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 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61N 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362

Abstract

A method of treating a medical condition in a patient using an implantable medical device, comprising providing an electrical signal generator; providing at least a first electrode operatively coupled to the electrical signal generator and to a vagus nerve of the patient; sensing cardiac data of the patient; determining at least a first cardiac parameter based upon said cardiac data; setting at least a first value; declaring an unstable brain state of a patient from said at least a first cardiac parameter and said at least a first value; and adjusting the at least a first value. Also, a computer readable program storage device encoded with instructions that, when executed by a computer, performs the method. In addition, the implantable medical device used in the method.

Claims

1. An implantable medical device (IMD) to treat a medical condition in a patient, the implantable medical device comprising:

a cardiac data sensing module operable to sense cardiac data of a patient;

a value setting module operable to set at least one first threshold value;

a cardiac module operable to determine at least one first cardiac parameter based upon sensed cardiac data from the cardiac data sensing module;

an unstable brain state declaration module that declaresan unstable brain state of the patient in response to the at least one first cardiac parameter satisfying the at least one first threshold value; and

an electrical signal generator configured to be operatively coupled to a vagus nerve of the patient;

wherein the electrical signal generator is configured to apply a first electrical signal configured to treat a chronic medical condition when the unstable brain state has not been declared, and wherein the electrical signal generator is configured to apply a second electrical signal configured to treat an acute medical condition when the unstable brains state has been declared.

2. The implantable medical device of claim 1, wherein the cardiac module is further operable to determine at least one second cardiac parameter based upon sensed cardiac data from the patient, and the unstable brain state declaration module declares the unstable brain state of the patient in response to the at least one first cardiac parameter and the at least one second cardiac parameter satisfying the at least first threshold value.

3. The implantable medical device of claim 1, wherein the unstable brain state declaration module declares the unstable brain state in response to a logical relationship between multiple parameters satisfying the at least one first threshold value, wherein the multiple parameters include the at least one first cardiac parameter.

4. The implantable medical device of claim 1, further comprising a non-cardiac parameter detection module configured to detect at least one non-cardiac parameter, wherein the unstable brain state declaration module uses the at least one non-cardiac parameter to confirm or deny the unstable brain state declared based on the at least on first cardiac parameter.

5. The implantable medical device of claim 1, wherein the value setting module adjusts the at least one first threshold value in response to a user request to adjust the at least one first threshold value.

6. The implantable medical device of claim 1, wherein the value setting module is operable to adjust the at least one first threshold value to render the unstable brain state declaration module less likely to declare the unstable brain state.

7. The implantable medical device of claim 1, wherein the value setting module is operable to adjust the at least one first threshold value to render the unstable brain state declaration module more likely to declare the unstable brain state.

8. The implantable medical device of claim 1, wherein the at least one first cardiac parameter includes at least one of an instantaneous heart rate, a moving average heart rate over a predetermined time period, a ratio of a first moving average heart rate over a first predetermined time period and a second moving average heart rate over a second predetermined time period, a rate of change of the patient'"'"'s heart rate, an elevation of the patient'"'"'s instantaneous heart rate above a baseline heart rate, a duration of an elevation of the patient'"'"'s heart rate above the patient'"'"'s baseline heart rate, a depression of the patient'"'"'s heart rate below the patient'"'"'s baseline heart rate, a duration of an elevation of the first moving average heart rate over the second moving average heart rate, an R-R interval, a PR segment interval, a PQ segment interval, a QRS interval, an ST segment interval, a statistical analysis heart parameter, a spectral analysis heart parameter, a fractal analysis heart parameter, an interbeat interval, an amplitude or a magnitude of a P wave, a Q wave, an R wave, an S wave, a T wave, a U wave, or any segment or interval between waves;

a change of the amplitude or magnitude of the wave or any segment or interval between waves;

or a rate of change of the amplitude or magnitude of the wave or any segment or interval between waves, and two or more thereof.

9. The implantable medical device of claim 1, further comprising a non-cardiac parameter detection module configured to detect at least one non-cardiac parameter including at least one of an activity level of the patient, an output of an accelerometer, a catamenial cycle, a time of day, an indicator of the patient'"'"'s sleep state, an inclination of the patient'"'"'s body, a dilation of a pupil of the patient, the patient'"'"'s body temperature, the patient'"'"'s blood pressure, and the patient'"'"'s electroencephalogram (EEG),

wherein the value setting module is operable to establish at least one second threshold value, and

wherein the unstable brain state declaration module declares the unstable brain state of the patient based on the at least one non-cardiac parameter satisfying the said at least one second threshold value.

10. The implantable medical device of claim 9, further comprising a memory that stores a value of the at least one non-cardiac parameter, and wherein the value setting module adjusts the at least one second threshold value based upon at least one of:

a timestamp at which the patient experienced the unstable brain state, cardiac data associated with the timestamp at which the patient experienced the unstable brain state, the activity level of the patient, the output of the accelerometer, the catamenial cycle, the time of day, the indicator of the patient'"'"'s sleep, the inclination of the patient'"'"'s body, the dilation of the pupil of the patient, the patient'"'"'s body temperature, the patient'"'"'s blood pressure, and the patient'"'"'s electroencephalogram (EEG).

11. The implantable medical device of claim 1, further comprising a memory that stores a timestamp associated with a declaration of unstable brain state.

12. The implantable medical device of claim 11, wherein the value setting module adjusts the at least one first threshold value based upon at least one of:

a timestamp at which the patient experienced the unstable brain state, cardiac data associated with the timestamp at which the patient experienced the unstable brain state, an activity level of the patient, an output of an accelerometer, a catamenial cycle, a time of day, an indicator of the patient'"'"'s sleep state, an inclination of the patient'"'"'s body, a dilation of a pupil of the patient, the patient'"'"'s body temperature, the patient'"'"'s blood pressure, and the patient'"'"'s electroencephalogram (EEG).

13. The implantable device of claim 11, wherein the value setting module is configured to:

perform an analysis of a log of times at which the patient experiences the unstable brain state to determine at least a first period when the patient has an increased frequency of unstable brain states, and

adjust the at least one first threshold value to render the unstable brain state declaration module more likely to declare the unstable brain state during a particular period based on the analysis.

14. The implantable device of claim 13, wherein the first period is less than one day.

15. A method of treating a medical condition in a patient using an implantable medical device, the method comprising:

sensing cardiac data of a patient;

determining at least one first cardiac parameter based upon the cardiac data;

declaring an unstable brain state of the patient when the at least one first cardiac parameter satisfies at least one first threshold value;

generating and applying a first electrical signal that is configured to treat a chronic medical condition to a vagus nerve of the patient when the unstable brain state has not been declared, and

generating and applying a second electrical signal that is configured to treat an acute medical condition to the vagus nerve of the patient when the unstable brain state has been declared.

16. The method of claim 15, further comprising adjusting the at least one first threshold value in response to a user request to adjust the at least one first threshold value.

17. The method of claim 15, further comprising adjusting the at least one first threshold value based on a correlation of the at least one first cardiac parameter with the patient experiencing the acute medical condition.

18. The method of claim 15, further comprising adjusting the at least one first threshold value based on the patient'"'"'s tolerance of the second electrical signal.

19. The method of claim 15, further comprising storing a timestamp associated with declaring the unstable brain state.

20. The method of claim 19, further comprising storing a time series of the at least one first cardiac parameter.

21. The method of claim 19, further comprising adjusting the at least one first threshold value based upon a plurality of timestamps associated with declaring the unstable brain state.

22. The method of claim 19, further comprising:

performing an analysis of a log that stores data indicating when the unstable brain state has been declared;

determining based on the analysis, at least one first period during which the patient experiences an increased frequency of unstable brain states; and

adjusting the at least one first threshold value to render declaring the unstable brain state more likely during the at least one first period.

23. The method of claim 15, further comprising adjusting the at least one first threshold value to render declaration of the unstable brain state more likely or less likely based on a severity of seizures suffered by the patient.

24. The method of claim 15, further comprising providing the patient with an alert regarding the unstable brain state.

25. A computer readable program storage device encoded with instructions that, when executed by a computer cause the computer to:

sense cardiac data of a patient;

determine at least one first cardiac parameter based upon the cardiac data;

declare an unstable brain state of the patient when the at least one first cardiac parameter satisfies at least one first threshold value;

instruct an electrical signal generator to generate and apply a first electrical signal that is configured to treat a chronic medical condition to a vagus nerve of the patient when the unstable brain state has not been declared, and

instruct the electrical signal generator to generate and apply a second electrical signal that is configured to treat an acute medical condition to the vagus nerve of the patient when the unstable brain state has been declared.