Systems and methods for reversibly blocking nerve activity

• US 20040127953A1
• Filed: 02/17/2004
• Published: 07/01/2004
• Est. Priority Date: 02/20/2001
• Status: Active Grant

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: Grill, Warren M, McIntyre, Cameron C, Mortimer, John Thomas, Kilgore, Kevin L.
• Granted Patent: US 7,389,145 B2
• Time in Patent Office: Days
• US Class Current: 607/46
• CPC Class Codes: A61N 1/32 alternating or intermittent currents applying electric fields by inductive or capacitive coupling A61N1/40; microwave apparatus A61N5/02
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36164 Sub-threshold or non-excitatory signals non-excitatory signals to the heart A61N1/3628
• CPC Class Codes: A61N 1/36171 Frequency
• CPC Class Codes: A61N 1/36178 Burst or pulse train parameters

Abstract

Systems and methods for blocking nerve impulses use an implanted electrode located on or around a nerve. A specific waveform is used that causes the nerve membrane to become incapable of transmitting an action potential. The membrane is only affected underneath the electrode, and the effect is immediately and completely reversible. The waveform has a low amplitude and can be charge balanced, with a high likelihood of being safe to the nerve for chronic conditions. It is possible to selectively block larger (motor) nerve fibers within a mixed nerve, while allowing sensory information to travel through unaffected nerve fibers.

Claims

1. A system for selectively blocking activity of a nerve in an animal by application of an electric current, the system comprising:

a processing element to generate an electrical stimulus waveform having a first phase that produces subthreshold depolarization of the nerve membrane through a cathodic pulse and a second anodic phase having a shorter duration than the first phase; and

,

an output to apply the waveform to a targeted nerve region.

2. The system as set forth in claim 1, wherein said second phase balances the charge of the first phase.

3. A method for selectively blocking activity of a nerve in an animal by application of an electric current, said method comprising:

generating an electrical stimulus waveform having a first phase that produces subthreshold depolarization of the nerve membrane through a cathodic pulse and a second anodic phase having a shorter duration than the first phase; and

,

applying the waveform to a targeted nerve region.

4. The method as set forth in claim 3, wherein said first and second phases are charged balanced.

5. A method for selectively blocking conduction of an action potential in a nerve of an animal such as a human, said method comprising:

delivering an electrical stimulation waveform to a nerve, said waveform comprising a series of bi-phasic stimulation pulses that, when applied to said nerve, block conduction of an action potential by said nerve.

6. The method as set forth in claim 5, wherein said nerve comprises h gates and m gates and wherein said bi-phasic pulses of said waveform close said h gates and said m gates sufficiently to block said nerve from conducting said action potential.

7. The method as set forth in claim 6, wherein each pulse of said electrical stimulus waveform comprises:

a first phase having a first polarity, a first duration and a first amplitude, said first amplitude less than an activation threshold of said nerve; and

,

a second phase having a second polarity, a second duration and a second amplitude.

8. The method as set forth in claim 7, wherein said second amplitude is greater than said first amplitude.

9. The method as set forth in claim 7, wherein said second duration is less than said first duration.

10. The method as set forth in claim 7, wherein said pulses of said waveform are delivered at a rate of between 0.5 Hertz (Hz) and 10 Hertz (Hz) inclusive.

11. The method as set forth in claim 7, wherein at least one of said first and second amplitude are increased over time to block conduction of said action potential in progressively smaller nerve fibers.

12. The method as set forth in claim 5, further comprising:

receiving a control signal, wherein said step of delivering said electrical stimulation waveform is carried out in response to receipt of said control signal.

13. The method as set forth in claim 12, further comprising:

monitoring at least one of electroneurogram (ENG) activity and electromyogram (EMG) activity of the animal of which said nerve is a part; and

,

using said at least one of said electroneurogram and electromyogram activity to derive said control signal.

14. The method as set forth in claim 5, wherein said pulses are charged balanced.

15. An apparatus for selectively blocking conduction of an action potential in a nerve of an animal such as a human, said apparatus comprising:

means for delivering to a nerve an electrical stimulation waveform comprising a series of bi-phasic stimulation pulses that, when applied to said nerve, block conduction of an action potential by said nerve.

16. The apparatus as set forth in claim 15, wherein each pulse of said electrical stimulus waveform comprises:

a first phase having a first polarity, a first duration and a first amplitude, said first amplitude less than an activation threshold of said nerve; and

,

a second phase having a second polarity, a second duration and a second amplitude.

17. The apparatus as set forth in claim 16, wherein said second amplitude is greater than said first amplitude.

18. The apparatus as set forth in claim 16, wherein said second duration is less than said first duration.

19. The apparatus as set forth in claim 16, wherein said pulses of said waveform are delivered at a rate of between 0.5 Hertz (Hz) and 10 Hertz (Hz) inclusive.

20. The apparatus as set forth in claim 15, further comprising:

means for monitoring at least one of electroneurogram (ENG) activity and electromyogram (EMG) activity of the animal of which said nerve is a part; and

,

means for deriving a control signal from said at least one of said electroneurogram and electromyogram activity, said means for delivering said electrical stimulation waveform operatively connected to said control signal deriving means whereby said means for delivering said stimulation waveform are operative in response to input from said control signal deriving means.