Contingent cardio-protection for epilepsy patients

• US 9,579,506 B2
• Filed: 10/09/2013
• Issued: 02/28/2017
• Est. Priority Date: 01/25/2008
• Status: Active Grant

• Current Assignee: Flint Hills Scientific, LLC
• Original Assignee: Flint Hills Scientific, LLC
• Inventors: Osorio, Ivan
• Primary Examiner(s): PATTON, AMANDA K
• Application Number:
  US14/050,173
• Publication Number:
  US 20140142653A1
• Time in Patent Office: 1,238 Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36064 Epilepsy
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36117 for treating hypertension
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

Disclosed are methods and systems for treating epilepsy by stimulating a main trunk of a vagus nerve, or a left vagus nerve, when the patient has had no seizure or a seizure that is not characterized by cardiac changes such as an increase in heart rate, and stimulating a cardiac branch of a vagus nerve, or a right vagus nerve, when the patient has had a seizure characterized by cardiac changes such as a heart rate increase.

Claims

1. A method of treating a patient having epilepsy comprising:

receiving at least one body data stream;

analyzing the at least one body data stream using a seizure detection algorithm to detect whether or not the patient has had an epileptic seizure;

receiving a cardiac signal of the patient;

analyzing the cardiac signal to determine the patient'"'"'s heart rate;

determining whether said epileptic seizure is characterized by a decrease in the patient'"'"'s heart rate from a reference value or a normative value;

applying a first electrical signal to a vagus nerve of the patient, based on said determination, wherein said determination is that the patient has not had an epileptic seizure, wherein the epileptic seizure is characterized by a decrease in the patient'"'"'s heart rate, wherein the first electrical signal is not a vagus nerve conduction blocking electrical signal; and

applying a second electrical signal to a vagus nerve of the patient, based on said determination, wherein said determination is that the patient has had an epileptic seizure, wherein the epileptic seizure is characterized by a decrease in the patient'"'"'s heart rate, wherein the second electrical signal is a pulsed electrical signal that blocks action potential conduction in the vagus nerve.

2. The method of claim 1, wherein determining that the patient has had an epileptic seizure characterized by a decrease in the patient'"'"'s heart rate comprises:

determining a first heart rate of the patient prior to detecting the onset of an epileptic seizure;

determining a second heart rate of the patient in response to detecting the onset of the epileptic seizure using said seizure detection algorithm;

comparing the first heart rate and the second heart rate; and

determining that the seizure is characterized by a decrease in the patient'"'"'s heart rate if the second heart rate is less than the first heart rate.

3. The method of claim 1, wherein applying the second electrical signal comprises applying a high frequency pulsed electrical signal to a target site of the vagus nerve, such that at least a fraction of the axons in the vagus nerve are incapable of supporting action potential propagation across the target site.

4. The method of claim 1, wherein applying the first electrical signal comprises applying an electrical signal according to a programmed duty cycle having at least a programmed on-time and a programmed off-time.

5. The method of claim 4, further comprising interrupting the applying of the first electrical signal based on said determination that the patient has had an epileptic seizure characterized by a decrease in the patient'"'"'s heart rate.

6. The method of claim 1 further comprising:

sensing the patient'"'"'s heart rate in response to providing the second electrical signal, and modifying the second electrical signal to maintain the patient'"'"'s heart rate between an upper and a lower heart rate range threshold.

7. The method of claim 1, wherein at least one of the first electrical signal and the second electrical signal is a microburst electrical signal characterized by having a number of pulses per microburst from 2 pulses to about 25 pulses, an interpulse interval of about 2 msec to about 50 msec, an interburst period of at least 100 msec, and a microburst duration of less than about 1 sec.

8. The method of claim 1 wherein the first electrical signal is selected from 1) an electrical signal that generates action potentials in at least a population of the nerve fibers of said vagus nerve, and 2) a subthreshold electrical signal that does not generate action potentials in a population of the fibers of said vagus nerve.

9. The method of claim 2, wherein determining a first heart rate comprises determining a heart rate during a non-seizure period.

10. The method of claim 2, further comprising issuing a warning that that the patient has had an epileptic seizure characterized by a decrease in the patient'"'"'s heart rate.

11. A method of treating a patient having epilepsy comprising:

sensing a cardiac signal and a kinetic signal of the patient;

analyzing at least one of the cardiac signal and the kinetic signal, comprising analyzing the cardiac signal to determine the patient'"'"'s heart rate;

determining whether or not the patient has had an epileptic seizure based on said analyzing;

in response to a determination that the patient has had an epileptic seizure, determining whether or not the epileptic seizure is characterized by a decrease in the patient'"'"'s heart rate from a reference value or a normative value,

applying a first electrical signal to a vagus nerve of the patient based on one of a) a determination that the patient has not had an epileptic seizure, and b) a determination that the patient has had an epileptic seizure that is not characterized by a decrease in the patient'"'"'s heart rate, wherein the first electrical signal is not a vagus nerve conduction blocking electrical signal; and

applying a second electrical signal to a vagus nerve of the patient based on a determination that the patient has had an epileptic seizure characterized by a decrease in the patient'"'"'s heart rate, wherein the second electrical signal is a pulsed electrical signal that blocks action potential conduction in the vagus nerve.

12. The method of claim 11, wherein applying the first electrical signal comprises applying the electrical signal according to a programmed duty cycle having at least a programmed on-time and a programmed off-time.

13. The method of claim 11, wherein applying the second electrical signal comprises applying a high frequency pulsed electrical signal to at target site of the vagus nerve using at least one electrode, such that at least a portion of the axons in the vagus nerve are incapable of supporting action potential propagation across the target site.