Granted Patent B2

US 9,402,550 · App. 13/097,439 · Granted Aug 2, 2016

Abstract

Claims (41)

1. A method, comprising:

sensing a time of beat sequence of a patient's heart;

processing the time of beat sequence with a medical device to identify a change in heart rate of a patient from a first heart rate to a second heart rate;

determining with the medical device a ratio of the second heart rate to the first heart rate;

continuously updating the first heart rate;

autonomously determining with the medical device a first dynamic ratio threshold for the ratio based on a first patient activity and a second dynamic ratio threshold for the ratio based on a second patient activity;

autonomously determining with the medical device a current dynamic ratio threshold for the ratio which is within a range between the first dynamic ratio threshold and the second dynamic ratio threshold, wherein the current dynamic ratio threshold is based upon a most recently updated window of the first heart rate;

comparing the ratio to the current dynamic ratio threshold; and

detecting a neurologic event based on an occurrence of the ratio exceeding the current dynamic ratio threshold.

2. The method of claim 1 , wherein the current dynamic ratio threshold decreases as the first heart rate increases.

3. The method of claim 1 , wherein the neurologic event is an epileptic seizure.

4. The method of claim 1 , further comprising:

initiating at least one responsive action selected from: logging at least one of a neurological event occurrence, a time of occurrence of the neurological event, or a severity measure of the neurological event; issuing a warning of the neurological event; issuing an alarm; initiating a responsive therapy to treat the neurologic event; and sending an email to at least one of the patient, a caregiver, a responder, and a physician.

5. The method of claim 4 , wherein the responsive therapy comprises applying an electrical signal to at least one cranial nerve selected from a vagus nerve, a trigeminal nerve, a glossopharyngeal nerve, a hypoglossal nerve, and branches of the foregoing.

6. The method of claim 1 , wherein:

the second heart rate comprises a first statistical measure of central tendency in a short-term window ending in a present time; and

the first heart rate comprises a second statistical measure of central tendency in a time window beginning prior to a start of the short-term window from which the second heart rate is determined.

7. The method of claim 1 , wherein determining the current dynamic ratio threshold is further based on the first heart rate and a maximum heart rate of the patient.

8. The method of claim 1 , wherein determining the current dynamic ratio threshold is further based on the first heart rate and a resting heart rate of the patient.

9. An article of manufacture comprising a computer-readable non-transitory storage medium having programming configured to cause processing circuitry to perform processing including:

sensing a time of beat sequence of a patient's heart;

processing the time of beat sequence with a medical device to identify a change in heart rate of a patient from a first heart rate to a second heart rate;

continuously updating the first heart rate;

determining with the medical device a ratio of the second heart rate to the first heart rate;

autonomously determining with the medical device a first dynamic ratio threshold for the ratio based on a first patient activity and a second dynamic ratio threshold for the ratio based on a second patient activity;

autonomously determining with the medical device a current dynamic ratio threshold for the ratio which is within a range between the first dynamic ratio threshold and the second dynamic ratio threshold, wherein the current dynamic ratio threshold is based upon a most recently updated window of the first heart rate;

comparing the ratio to the current dynamic ratio threshold; and

detecting a neurologic event based on an occurrence of the ratio exceeding the current dynamic ratio threshold.

10. The article of claim 9 , wherein the current dynamic ratio threshold decreases as the first heart rate increases.

11. The article of claim 9 , wherein the neurologic event is an epileptic seizure.

12. The article of claim 9 , wherein the first heart rate is a background heart rate and the second heart rate is a foreground heart rate.

13. An apparatus, comprising:

at least one sensor configured to sense a time of beat sequence of a patient's heart;

a medical device comprising:

a) a heart rate determination module configured to identify from the time of beat sequence a change in heart rate of a patient from a first heart rate to a second heart rate, and continuously update the first heart rate;

b) a parameter determination module configured to determine a ratio of the second heart rate to the first heart rate;

c) a dynamic threshold determination module configured to autonomously determine a first dynamic ratio threshold for the ratio based on a first patient activity and a second dynamic ratio threshold for the ratio based on a second patient activity, the dynamic threshold determination module configured to autonomously determining with the medical device a current dynamic ratio threshold for the ratio which is within a range between the first dynamic ratio threshold and the second dynamic ratio threshold, wherein the current dynamic ratio threshold is based upon a most recently updated window of the first heart rate; and

d) a comparison module configured to compare the ratio to the current dynamic ratio threshold; and

e) a neurologic event detection module configured to detect a neurologic event based on an occurrence of the ratio exceeding the current dynamic ratio threshold.

14. The apparatus of claim 13 , wherein the current dynamic ratio threshold determined by the dynamic threshold determination module decreases as the first heart rate increases.

15. The apparatus of claim 13 , wherein the at least one sensor and the medical device are configured to be implanted in the patient.

Assignments (7)