METHODS AND APPARATUS FOR CONTROLLING NEUROSTIMULATION USING EVOKED PHYSIOLOGIC EVENTS

• US 20110313484A1
• Filed: 06/09/2011
• Published: 12/22/2011
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Hincapie Ordonez, Juan Gabriel, Ternes, David J., Hamann, Jason J., Ruble, Stephen
• Granted Patent: US 9,265,431 B2
• Time in Patent Office: Days
• US Class Current: 607/17
• CPC Class Codes: A61B 5/24 Detecting, measuring or recording bioelectric or biomagnetic signals of the body or parts thereof
• CPC Class Codes: A61B 5/4041 Evaluating nerves condition
• CPC Class Codes: A61B 5/4047 afferent nerves, i.e. nerves that relay impulses to the central nervous system
• CPC Class Codes: A61B 5/4058 for evaluating the central nervous system A61B5/4806, A61B5/4821 take precedence
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36071 Pain
• 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 1/36128 Control systems
• CPC Class Codes: A61N 1/36135 using physiological parameters
• CPC Class Codes: A61N 1/36139 with automatic adjustment
• CPC Class Codes: A61N 1/36167 Timing, e.g. stimulation onset

Abstract

A neurostimulation system provides for capture verification and stimulation intensity adjustment to ensure effectiveness of vagus nerve stimulation in modulating one or more target functions in a patient. In various embodiments, stimulation is applied to the vagus nerve, and evoked responses are detected to verify that the stimulation captures the vagus nerve and to adjust one or more stimulation parameters that control the stimulation intensity.

Claims

1. A system for delivering neurostimulation to a body having a vagus nerve and a laryngeal muscle, the system comprising:

a stimulation output circuit configured to deliver neurostimulation pulses to the vagus nerve;

an evoked response detection circuit configured to receive a physiological signal indicative of evoked responses being physiologic events evoked by the neurostimulation pulses and detect the evoked responses using the physiological signal and one or more detection thresholds; and

a control circuit including a sensing parameter adjustor configured to adjust the one or more detection thresholds using the detected evoked responses and a stored baseline response.

2. The system of claim 1, wherein the evoked response detection circuit is configured to generate one or more response signals representative of the detected evoked responses, and the control circuit is configured to control the delivery of the neurostimulation pulses using the one or more response signals.

3. The system of claim 1, wherein the evoked response detection circuit comprises an evoked neural response detection circuit configured to receive a neural signal representative of neural activities in the vagus nerve including evoked neural responses each evoked by one of the neurostimulation pulses and detect the evoked neural responses using the one or more detection thresholds.

4. The system of claim 1, wherein the evoked response detection circuit comprises an evoked muscular response detection circuit configured to receive a laryngeal signal representative of activities of the laryngeal muscle including evoked muscular responses each evoked by one of the neurostimulation pulses and detect the evoked muscular responses using the one or more detection thresholds.

5. The system of claim 4, wherein the laryngeal signal comprises an electromyographic (EMG) signal, and comprising an EMG sensing circuit configured to sense the EMG signal.

6. The system of claim 4, wherein the laryngeal signal comprises an acceleration signal, and comprising:

an accelerometer configured to sensing the acceleration signal; and

an activity sensing circuit configured to be coupled to the accelerometer to sense the acceleration signal.

7. The system of claim 4, wherein the laryngeal signal comprises a voice signal, and comprising:

a voice sensor configured to sensing the voice signal; and

a voice sensing circuit configured to be coupled to the voice sensor to sense the voice signal.

8. The system of claim 1, wherein the control circuit comprises a sensing adjustment timer configured to adjust the one or more detection thresholds using the detected evoked responses and the stored baseline response according to a specified schedule.

9. The system of claim 1, comprising an implantable medical device including the neurostimulation output circuit, the evoked neural response detection circuit, and the control circuit.

10. The system of claim 9, wherein the implantable medical device further includes a cardiac rhythm management device.

11. A method for delivering neurostimulation to a body having a vagus nerve and a laryngeal muscle, the method comprising:

delivering neurostimulation pulses to the vagus nerve;

sensing a physiological signal indicative of evoked responses each being a physiologic event evoked by one of the neurostimulation pulses;

detecting the evoked responses by comparing the physiological signal to one or more detection thresholds; and

adjusting the one or more detection thresholds using the detected evoked responses.

12. The method of claim 11, comprising:

comparing the detected evoked responses to a stored baseline response; and

adjusting the one or more detection thresholds using an outcome of the comparison of the detected evoked responses to the stored baseline response.

13. The method of claim 12, wherein sensing the physiological signal comprises sensing a neural signal representative of neural activities in the vagus nerve including evoked neural responses each evoked by one of the neurostimulation pulses, detecting the evoked responses comprises detecting the evoked neural responses by comparing the neural signal to the one or more detection thresholds, and adjusting the one or more detection thresholds comprises adjusting the one or more detection thresholds using the detected evoked neural responses.

14. The method of claim 12, wherein sensing the physiological signal comprises sensing a laryngeal signal representative of activities of the laryngeal muscle including evoked muscular responses each evoked by one of the neurostimulation pulses, detecting the evoked responses comprises detecting the evoked muscular responses by comparing the laryngeal signal to the one or more detection thresholds, and adjusting the one or more detection thresholds comprises adjusting the one or more detection thresholds using the detected evoked muscular responses.

15. The method of claim 12, wherein comparing the detected evoked responses to the stored baseline response comprises:

producing an evoked response waveform representative of the detected evoked responses; and

comparing the evoked response waveform to a stored baseline waveform.

16. The method of claim 12, wherein comparing the detected evoked responses to the stored baseline response comprises:

measuring one or more characteristic parameters of the detected evoked responses; and

comparing the one or more characteristic parameters to stored one or more baseline characteristic parameters.

17. The method of claim 16, wherein measuring the one or more characteristic parameters of the detected evoked responses comprises measuring the one or more characteristic parameters each as an average value from the detected evoked responses.

18. The method of claim 12, comprising producing an alert signal in response to the detected evoked responses substantially deviating from the stored baseline response.

19. The method of claim 11, comprising adjusting the one or more detection thresholds according to a specified schedule.

20. The method of claim 11, comprising adjusting the one or more detection thresholds in response to a user command.