DELIVERING SCHEDULED AND UNSCHEDULED THERAPY WITHOUT DETRIMENT TO BATTERY LIFE OR ACCURACY OF LONGEVITY PREDICTIONS

• US 20110270359A1
• Filed: 04/28/2010
• Published: 11/03/2011
• Est. Priority Date: 04/28/2010
• Status: Active Grant

• Current Assignee: Cyberoncs, Inc.
• Original Assignee: Cyberonics, Inc
• Inventors: COLBORN, John C.
• Granted Patent: US 8,874,229 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61N 1/025 Digital circuitry features of electrotherapy devices, e.g. memory, clocks, processors
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362
• CPC Class Codes: A61N 1/378 Electrical supply

Abstract

A method comprises applying a first open-loop electrical signal to a neural structure at a first rate. The method also comprises applying a closed-loop electrical signal to the neural structure in response to an event detection, thus causing an overall rate at which electrical stimulation is applied to the neural structure to exceed the first rate. The method further comprises applying a second open-loop electrical signal to a neural structure at a second rate that is lower than the first rate, thus causing the overall rate to be reduced to the first rate.

Claims

1. A method of providing electrical neurostimulation therapy to a patient to treat a medical condition, wherein said electrical neurostimulation therapy includes both an open-loop therapy mode and a closed-loop therapy mode and is characterized by a combined rate of electrical charge delivery to a neural structure, the method comprising:

applying a first open-loop electrical signal to the neural structure, said first open-loop signal defined by a plurality of parameters and characterized by a first open-loop rate of electrical charge delivery to the neural structure, said first open-loop rate determined by said plurality of parameters defining said first open-loop signal;

in response to a detection event, applying a closed-loop electrical signal to the neural structure, thereby causing said combined rate of electrical charge delivery to exceed said first open-loop rate;

adjusting at least one of said plurality of parameters defining said first open-loop signal to define a second open-loop electrical signal characterized by a second open-loop rate of electrical charge delivery less than said first open-loop rate;

applying said second open-loop electrical signal to said neural structure according to the second open-loop rate until said combined rate of electrical charge delivery is reduced to said first closed-loop rate; and

resuming applying said first open-loop electrical signal to said neural structure.

2. The method of claim 1, wherein said first open-loop electrical signal comprises applying a plurality of pulse bursts to said neural structure separated by an off-time period, and wherein applying said second open-loop electrical signal to said neural structure according to the second open-loop rate comprises skipping at least one burst of said first open-loop electrical signal after said application of the closed-loop electrical signal.

3. The method of claim 1, wherein said first open-loop electrical signal comprises a plurality of pulse bursts separated by a first programmed off-time period, and said second open-loop electrical signal comprises at least one pulse burst followed by a second off-time period, said method further comprising:

determining an early intervention time associated with applying the closed-loop electrical signal to said neural structure, said early intervention time comprising the difference between the first programmed off-time period and an actual off-time elapsed at the time of applying the closed-loop electrical signal to the neural structure; and

wherein said second off-time period is determined by adding at least a portion of said early intervention time to said first programmed off-time period.

4. The method of claim 1, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, wherein applying said second open-loop electrical signal to said neural structure comprises delivering n electrical pulse bursts after application of said closed-loop electrical signal;

and wherein said n electrical pulse bursts are defined by a second on-time less than said first on-time.

5. The method of claim 1, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, and said second open-loop electrical signal comprises at least one pulse burst having a second on-time followed by a second off-time,

wherein applying said closed-loop electrical signal comprises generating a closed-loop electrical signal having a duration defined by a fraction of said first programmed off-time;

and

wherein said second on-time is defined by a second fraction of said first programmed off-time.

6. A system, comprising:

detection logic adapted to detect an event; and

stimulation logic coupled to the detection logic and adapted to apply electrical stimulation therapy to a neural structure using one or both of an open-loop therapy mode and a closed-loop therapy mode, wherein said electrical stimulation therapy is characterized by a combined rate of electrical charge delivery to the neural structure;

wherein the stimulation logic applies a first open-loop electrical signal to the neural structure, the first open-loop electrical signal characterized by a plurality of parameters and by a first rate of electrical charge delivery to the neural structure that is determined by said plurality of parameters, and wherein said combined rate is said first rate;

wherein, upon receiving a notification from the detection logic as a result of the detection of said event, the stimulation logic applies a closed-loop electrical signal to the neural structure such that the combined rate exceeds said first rate;

wherein, upon applying said closed-loop signal to the neural structure, the stimulation logic adjusts one or more of said plurality of parameters to define a second open-loop electrical signal characterized by a second rate of charge delivery less than said first rate.

7. The system of claim 6 wherein the stimulation logic applies said second open-loop electrical signal to the neural structure until the combined rate is reduced to said first rate, and

wherein the stimulation logic resumes applying said first open-loop electrical signal to the neural structure.

8. The system of claim 7, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, wherein, to adjust said one or parameters to define a second open-loop signal, the stimulation logic imposes an off-time duration sufficient to cause said combined rate to equal said first rate following application of the closed-loop electrical signal;

and

wherein the stimulation logic resumes applying said first open-loop electrical signal to the neural structure.

9. The system of claim 6, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first programmed on-time, and separated by a first programmed off-time, and wherein, to adjust one or more of said plurality of parameters, the stimulation logic skips the next programmed burst of said first open-loop electrical signal after said application of the closed-loop electrical signal.

10. The system of claim 6, wherein said first open-loop electrical signal comprises a plurality of pulse bursts separated by a first programmed off-time period, and said second open-loop electrical signal comprises at least one pulse burst followed by a second off-time period;

wherein the stimulation logic determines an early intervention time associated with applying the closed-loop electrical signal to said neural structure, said early intervention time comprising the difference between the first programmed off-time period and an actual off-time elapsed at the time the closed-loop electrical signal is applied to the neural structure; and

wherein said second off-time period is determined by adding at least a portion of said early intervention time to said first programmed off-time period.

11. The system of claim 6, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, and wherein, to apply said second open-loop electrical signal to said neural structure, the stimulation logic delivers n electrical pulse bursts after application of said closed-loop electrical signal;

and wherein said n electrical pulse bursts are defined by a second on-time less than said first on-time.

12. The system of claim 6, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, and said second open-loop electrical signal comprises at least one pulse burst having a second on-time followed by a second off-time,

wherein, to apply said closed-loop electrical signal, the stimulation logic generates a closed-loop electrical signal having a duration defined by a fraction of said first programmed off-time;

and

wherein said second on-time is defined by a second fraction of said first programmed off-time.

13. A method, comprising:

applying a first open-loop electrical signal to a neural structure at a first charge delivery rate;

applying a closed-loop electrical signal to the neural structure in response to an event detection, thus causing an overall charge delivery rate to the neural structure exceeding the first charge delivery rate; and

applying a second open-loop electrical signal to a neural structure at a second charge delivery rate that is lower than the first charge delivery rate, thus causing said overall charge delivery rate to approach the first charge delivery rate.

14. The method of claim 13, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first programmed on-time, and separated by a first programmed off-time,

and wherein applying said second open-loop electrical signal to said neural structure at the second charge delivery rate comprises waiting for an amount of time sufficient to cause said combined rate to equal said first rate between said application of the closed-loop electrical signal and resuming delivery of said first open-loop electrical signal.

15. The method of claim 13, wherein said first open-loop electrical signal comprises a plurality of programmed electrical pulse bursts having a duration defined by a first programmed on-time, and separated by a first programmed off-time, and

wherein applying said second open-loop electrical signal to said neural structure according to the second rate comprises skipping the next programmed pulse burst of said first open-loop electrical signal after said application of the closed-loop electrical signal.

16. The method of claim 13, wherein said first open-loop electrical signal comprises a plurality of pulse bursts separated by a first programmed off-time period, and said second open-loop electrical signal comprises at least one pulse burst followed by a second off-time period, said method further comprising:

determining an early intervention time associated with applying the closed-loop electrical signal to said neural structure, said early intervention time comprising the difference between the first programmed off-time period and an actual off-time elapsed at the time of applying the closed-loop electrical signal to the neural structure; and

wherein said second off-time period is determined by adding at least a portion of said early intervention time to said first programmed off-time period.

17. The method of claim 16, further comprising adding the at least a portion of said difference to multiple off-cycles following said application of the closed-loop electrical signal.

18. The method of claim 13, wherein said first open-loop electrical signal comprises a plurality of electrical pulse bursts having a duration defined by a first on-time, and separated by a first programmed off-time, wherein applying said second open-loop electrical signal to said neural structure comprises delivering n electrical pulse bursts after application of said closed-loop electrical signal;

and wherein said n electrical pulse bursts are defined by a second on-time less than said first on-time.