Vagus nerve stimulation method

• US 8,280,505 B2
• Filed: 03/10/2009
• Issued: 10/02/2012
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Catholic Healthcare West (CommonSpirit Health (Illinois))
• Original Assignee: Catholic Healthcare West (CommonSpirit Health (Illinois))
• Inventors: Craig, Arthur D.
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): MALAMUD, DEBORAH LESLIE
• Application Number:
  US12/400,893
• Publication Number:
  US 20090171405A1
• Time in Patent Office: 1,302 Days
• Field of Search: 607 1- 2, 607 6- 7, 607/9, 607/45, 607/115, 607118-119
• US Class Current: 607/2
• 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 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/353 Detecting P-waves
• CPC Class Codes: A61B 5/355 Detecting T-waves
• CPC Class Codes: A61B 5/369 Electroencephalography [EEG] devices for psychotechnics A61B5/16
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• 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 1/36082 Cognitive or psychiatric applications, e.g. dementia or Alzheimer's disease
• CPC Class Codes: A61N 1/3611 Respiration control stimulating respiratory organs A61N1/3601
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36178 Burst or pulse train parameters

Abstract

An implanted electrical signal generator delivers a novel exogenous electrical signal to a vagus nerve of a patient. The vagus nerve conducts action potentials originating in the heart and lungs to various structures of the brain, thereby eliciting a vagal evoked potential in those structures. The exogenous electrical signal simulates and/or augments the endogenous afferent activity originating from the heart and/or lungs of the patient, thereby enhancing the vagal evoked potential in the various structures of the brain. The exogenous electrical signal includes a series of electrical pulses organized or patterned into a series of microbursts including 2 to 20 pulses each. No pulses are sent between the microbursts. Each of the microbursts may be synchronized with the QRS wave portion of an ECG. The enhanced vagal evoked potential in the various structures of the brain may be used to treat various medical conditions including epilepsy and depression.

Claims

1. A method of treating a brain disorder in a patient having a cardiac cycle, a vagus nerve, and a brain, the method comprising:

detecting at least a portion of the cardiac cycle of the patient;

applying to a selected location on the vagus nerve of the patient, in response to having detected the portion of the cardiac cycle of the patient, a pulsed electrical signal configured to increase afferent activity on the vagus nerve to be conducted thereby to the brain to treat the brain disorder, the pulsed electrical signal being selected from the group consisting of a single microburst and a plurality of microbursts, wherein each microburst of the pulsed electrical signal is applied to the selected location on the vagus nerve of the patient, and wherein each microburst of the pulsed electrical signal is patterned and comprises;

from 2 to 6 pulses per microburst;

at least one interpulse interval between adjacent pulses of the microburst, each interpulse interval ranging from about 5 to about 10 milliseconds; and

a microburst duration less than or equal to 100 milliseconds.

2. The method of claim 1 wherein detecting the portion of the cardiac cycle of the patient comprises:

detecting a portion of a QRS complex of the patient'"'"'s cardiac cycle, and

applying the pulsed electrical signal comprises synchronizing the application of the pulsed electrical signal to the vagus nerve of the patient with a QRS complex of the patient'"'"'s cardiac cycle.

3. The method of claim 1 wherein detecting the portion of the cardiac cycle of the patient comprises detecting an R wave of the patient'"'"'s cardiac cycle, and wherein applying the pulsed electrical signal comprises applying the pulsed electrical signal to the vagus nerve of the patient after a delay period following detection of each of a plurality of R waves of the patient.

4. The method of claim 3 wherein said delay period comprises from about 10 milliseconds to about 1000 milliseconds following detection of each of said plurality of R waves.

5. The method of claim 4 wherein said delay period comprises from about 10 milliseconds to about 500 milliseconds following detection of each of said plurality of R waves.

6. The method of claim 3 wherein said delay periods comprise random time periods within a specified range of delay values.

7. The method of claim 1 wherein the pulsed electrical signal comprises a plurality of microbursts, and wherein each microburst other than the last of said plurality of microbursts is separated from an adjacent microburst by an interburst period of from about 100 milliseconds to about six seconds.

8. The method of claim 1 wherein the pulsed electrical signal comprises a plurality of microbursts, and wherein the plurality of microbursts are applied to the vagus nerve at a microburst frequency of about 10 Hz to about 0.25 Hz.

9. The method of claim 1, further comprising:

providing at least one electrode;

providing at least one sensor;

coupling the at least one electrode to the vagus nerve of the patient;

providing an electrical signal generator coupled to the electrode;

detecting the portion of the cardiac cycle of the patient using the at least one sensor;

generating the pulsed electrical signal using the electrical signal generator; and

applying the pulsed electrical signal to the at least one electrode.

10. The method of claim 1 wherein the brain disorder is selected from the group consisting of epilepsy, neuropsychiatric disorders including but not limited to depression, eating disorders including obesity, traumatic brain injury, coma, addiction disorders, dementia, sleep disorders, pain, and migraine.

11. The method of claim 1 wherein a sum of the interpulse intervals separating the pulses of each of the microbursts is less than about 60 milliseconds.

12. The method of claim 1 wherein the pulsed electrical signal is applied to augment natural endogenous afferent vagal activity.

13. The method of claim 1 further comprising not providing the pulsed electrical signal during at least a portion of the cardiac cycle of the patient.

14. The method of claim 1 wherein detecting the portion of the cardiac cycle of the patient comprises acoustically detecting at least a portion of the cardiac cycle of the patient.

15. The method of claim 1 further comprising:

detecting at least a portion of a respiratory cycle of the patient;

wherein applying the pulsed electrical signal to the vagus nerve further comprises applying the pulsed electrical signal in response to having detected the portion of the respiratory cycle of the patient.

16. The method of claim 1 wherein each microburst comprises from 3 to 5 pulses per microburst, wherein the at least one interpulse interval comprises a plurality of interpulse intervals, and wherein at least one interpulse interval of the plurality of interpulse intervals in each microburst is selectively varied from the other interpulse intervals.

17. A method of treating a medical condition in a patient having a cardiac cycle, a respiratory cycle, and a vagus nerve, the method comprising:

detecting at least a portion of the cardiac cycle of the patient;

detecting at least a portion of the respiratory cycle of the patient, wherein detecting the portion of the respiratory cycle of the patient comprises detecting one of an inspiration of breath and an expiration of breath; and

in response to detecting the portion of the cardiac cycle of the patient and the portion of the respiratory cycle of the patient, applying a pulsed electrical signal to the vagus nerve of the patient, the pulsed electrical signal comprising a plurality of microbursts, wherein applying the pulsed electrical signal comprises applying a microburst to the vagus nerve of the patient after a delay period following the detection of one of the inspiration of breath and the expiration of breath, and wherein each microburst is separated from an adjacent microburst by an interburst period of at least 100 milliseconds and each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second.

18. The method of claim 17 wherein the delay period following the detection of the one of the inspiration of breath and the expiration of breath is about 0.5 seconds to about 1.0 seconds after the detection of the inspiration of breath.

19. The method of claim 17 wherein applying the pulsed electrical signal comprises applying a microburst to the vagus nerve of the patient within about 250 milliseconds after the detection of the inspiration of breath.

20. A method of treating a medical condition in a patient having a cardiac cycle, a vagus nerve, and a brain, the method comprising:

applying a first pulsed electrical signal comprising a plurality of microbursts to the vagus nerve of the patient;

measuring a first enhanced Vagal Evoked Potential (eVEP) in a target area of the patient'"'"'s brain;

changing at least one of a number of pulses per microburst, an interpulse interval between adjacent pulses of the microburst, a microburst duration, and an interburst period to provide a second pulsed electrical signal comprising a plurality of microbursts;

applying the second pulsed electrical signal to the vagus nerve of the patient;

measuring a second eVEP in the target area of the patient'"'"'s brain;

comparing the first eVEP and the second eVEP;

selecting one of the first electrical signal and the second electrical signal for continued application to the vagus nerve of the patient based upon the comparing;

detecting at least a portion of the cardiac cycle of the patient; and

in response to detecting the portion of the cardiac cycle of the patient, applying the selected electrical signal to the vagus nerve of the patient, wherein each of the microbursts of the first and second electrical signals is separated from an adjacent microburst by an interburst period of at least 100 milliseconds and each microburst is characterized by;

from 2 to 20 pulses per microburst;

an interpulse interval between adjacent pulses of the microburst of from about 1 to about 20 milliseconds; and

a microburst duration of not greater than 1 second.

21. The method of claim 20 wherein the target area of the patient'"'"'s brain is selected from the group consisting of the right thalamus, the right striatum, and the left insular cortex.

22. A method comprising:

for a patient having a brain, a vagus nerve, a cardiac cycle, and a neuropsychiatric disorder, detecting an R-wave of the cardiac cycle of the patient;

applying to a selected location on the vagus nerve of the patient, in response to having detected the R-wave of the cardiac cycle of the patient, a pulsed electrical signal configured to increase afferent activity on the vagus nerve to be conducted thereby to the brain to treat the neuropsychiatric disorder, the pulsed electrical signal being selected from the group consisting of a single microburst and a plurality of microbursts, wherein each microburst of the pulsed electrical signal is applied to the selected location on the vagus nerve of the patient, and wherein each microburst of the pulsed electrical signal is patterned and comprises;

from 2 to 6 pulses per microburst;

at least one interpulse interval between adjacent pulses of the microburst, each interpulse interval ranging from about 5 to about 10 milliseconds; and

a microburst duration less than or equal to 100 milliseconds.

23. The method of claim 22 wherein the neuropsychiatric disorder is depression.

24. A method of treating a brain disorder in a patient having a cardiac cycle, a vagus nerve, and a brain, the method comprising:

detecting at least a portion of the cardiac cycle of the patient;

applying to a selected location on the vagus nerve of the patient, in response to having detected the portion of the cardiac cycle of the patient, a pulsed electrical signal configured to increase afferent activity on the vagus nerve to be conducted thereby to the brain to treat the brain disorder, the pulsed electrical signal being selected from the group consisting of a single microburst and a plurality of microbursts, wherein each microburst of the pulsed electrical signal is applied to the selected location on the vagus nerve of the patient, and wherein each microburst of the pulsed electrical signal is patterned and comprises;

a plurality of pulses per microburst;

a plurality of interpulse intervals between adjacent pulses of the microburst, wherein each interpulse interval is between about 5 to about 10 milliseconds, and wherein at least one interpulse interval of the plurality of interpulse intervals in each microburst is selectively varied from the other interpulse intervals; and

a microburst duration less than or equal to 100 milliseconds.

25. The method of claim 24 wherein the plurality of pulses comprises between 3 and 20 pulses per microburst.

26. The method of claim 24 wherein detecting the portion of the cardiac cycle of the patient comprises:

detecting a portion of a QRS complex of the patient'"'"'s cardiac cycle, and

applying the pulsed electrical signal comprises synchronizing the application of the pulsed electrical signal to the vagus nerve of the patient with a QRS complex of the patient'"'"'s cardiac cycle.

27. The method of claim 24 wherein detecting the portion of the cardiac cycle of the patient comprises detecting an R wave of the patient'"'"'s cardiac cycle, and wherein applying the pulsed electrical signal comprises applying the pulsed electrical signal to the vagus nerve of the patient after a delay period following detection of the R wave.

28. The method of claim 27 wherein said delay period comprises from about 10 milliseconds to about 1000 milliseconds following detection of the R wave.

29. The method of claim 27 wherein the pulsed electrical signal comprises a plurality of microbursts, wherein the step of applying the pulsed electrical signal comprises applying at least one of the plurality of microbursts to the vagus nerve of the patient after a delay period following detection of each of a plurality of R waves of the patient, and wherein said delay periods comprise random time periods within a specified range of delay values.

30. The method of claim 24 wherein detecting the portion of the cardiac cycle of the patient comprises detecting an T wave of the patient'"'"'s cardiac cycle, and wherein applying the pulsed electrical signal comprises applying the pulsed electrical signal to the vagus nerve of the patient after a delay period following detection of the T wave.