Dynamic cranial nerve stimulation based on brain state determination from cardiac data
View Patent ↗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.
1. An medical device comprising:
a cardiac data sensing module operable to sense cardiac data;
a value setting module operable to set a first cardiac threshold value and dynamically adjust the first cardiac threshold value based upon sensed cardiac data from the cardiac sensing module;
a cardiac module operable to determine a first cardiac parameter based upon sensed cardiac data from the cardiac sensing module;
an unstable brain state declaration module operable to declare a seizure when the first cardiac parameter exceeds the first cardiac threshold value.
2. The medical device of claim 1 , wherein:
the value setting module is operable to set a second cardiac threshold value and dynamically adjust the second cardiac threshold value based upon sensed cardiac data from the cardiac data sensing module;
the cardiac module is operable to determine a second cardiac parameter based upon sensed cardiac data; and
the unstable brain state declaration module is further operable to declare a seizure when the second cardiac parameter exceeds the second cardiac threshold value.
3. The medical device of claim 1 , further comprising:
a non-cardiac data sensing module operable to sense non-cardiac data;
the value setting module operable to set a first non-cardiac threshold value and dynamically adjust the first non-cardiac threshold value based upon sensed non-cardiac data from the non-cardiac sensing module;
a non-cardiac module operable to determine a first non-cardiac parameter based upon sensed non-cardiac data from the non-cardiac data sensing module; and
the unstable brain state declaration module operable to declare an a seizure when the first non-cardiac parameter exceeds the first non-cardiac threshold value.
4. The medical device of claim 3 , wherein:
the value setting module is further operable to apply a weighting factor to the first cardiac threshold value and the first non-cardiac threshold value; and
the unstable brain state declaration module is operable to utilize the weighted first cardiac threshold value and the first non-cardiac threshold value in declaring a seizure.
5. The medical device of claim 3 , wherein the first non-cardiac parameter is selected from the group comprising:
an activity level;
an output of an accelerometer;
a catamenial cycle;
a time of day;
an indicator of a sleep state;
an inclination of a body;
a pupil dilation;
a body temperature;
a blood pressure; and
an electroencephalogram (EEG).
6. The medical device of claim 1 , wherein the value setting module sets the first cardiac threshold value in response to a user request to set the first cardiac threshold value.
7. The medical device of claim 1 , wherein the value setting module adjusts the first cardiac threshold value in response to a user request to adjust the first cardiac threshold value.
8. The medical device of claim 1 , wherein the value setting module is operable to adjust the first cardiac threshold value to render the unstable brain state declaration module more likely to declare a seizure.
9. The medical device of claim 1 , wherein the value setting module is operable to adjust the first cardiac threshold value to render the unstable brain state declaration module less likely to declare a seizure.
10. The medical device of claim 1 , wherein the first cardiac parameter is selected from the group comprising:
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 a heart rate;
an elevation of an instantaneous heart rate above a baseline heart rate;
a duration of an elevation of a heart rate above a baseline heart rate;
a depression of a heart rate below a baseline heart;
a duration of an elevation of a first moving average heart rate over a 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, Q wave, R wave, S wave, T wave, U wave;
a change in amplitude or a magnitude of a P wave, Q wave, R wave, S wave, T wave, U wave; and
a rate of change an amplitude or magnitude of a P wave, Q wave, R wave, S wave, T wave, U wave.
11. The medical device of claim 1 , further comprising a memory that stores a timestamp associated with a declaration of a seizure.
12. The medical device of claim 11 , wherein the value setting module is further configured to adjust a threshold value based upon the timestamp at which a seizure is declared.
13. The medical device of claim 11 , wherein the value setting module is further configured to:
perform an analysis of a log of times at which a seizure was declared to determine a first period when an increased frequency of seizure declarations are likely to occur; and
adjust the first cardiac threshold value to render the unstable brain state declaration module more likely to declare a seizure during the first period.
14. The medical device of claim 1 , wherein the medical device comprises an implantable medical device (IMD).
15. A method of declaring a seizure using a medical device, comprising:
sensing cardiac data;
setting a first cardiac threshold value based upon the sensed cardiac data;
dynamically adjusting the first cardiac threshold value based upon the sensed cardiac data;
determining a first cardiac parameter based upon the sensed cardiac data; and
declaring a seizure in response to the first cardiac parameter exceeding the first cardiac threshold value.
16. The method of claim 15 , further comprising:
setting a second cardiac threshold value based upon the sensed cardiac data;
dynamically adjusting the second cardiac threshold value based upon the sensed cardiac data;
determining a second cardiac parameter based upon the sensed cardiac data; and
declaring a seizure in response to the second cardiac parameter satisfying the second cardiac threshold value.
17. The method of claim 16 , further comprising:
applying a weighting factor to the first cardiac threshold value and the second cardiac threshold value; and
utilizing the weighted first cardiac threshold value and the weighted second cardiac threshold value in declaring seizure.
18. The method of claim 15 , further comprising storing a timestamp associated with declaring a seizure.
19. The method of claim 18 , further comprising adjusting a threshold value based upon the timestamp at which a seizure is declared.
20. The method of claim 18 , further comprising:
performing an analysis of a log of times at which a seizure was declared to determine a first period when an increased frequency of seizure declarations are likely to occur; and
adjusting the first cardiac threshold value to render the unstable brain state declaration module more likely to declare a seizure during the first period.