Subthreshold direct current (DC) nerve conduction block after suprathreshold “priming”
A DC nerve conduction block can be maintained by delivering a subthreshold direct current (DC) after priming a neural structure with a suprathreshold DC. A waveform generator can provide a DC waveform including a first phase with a first amplitude capable of providing a nerve conduction block of a neural structure within 1 second and a second phase with a second amplitude less than the first amplitude. One or more electrodes can deliver the first phase for to the neural structure for a first time to provide the nerve conduction block of the neural structure within 1 second and deliver the second phase to the neural structure for a second time to maintain the block of the neural structure. By maintaining the DC nerve conduction block with the subthreshold DC, significant power can be saved, resulting in an extended battery life of the waveform generator.
1 . A method for accelerating a recovery time of a neural structure after ending a conduction block of the neural structure with only a direct current waveform having at least two phases, the method comprising:
providing a first phase of the direct current waveform from a waveform generator to one or more electrodes, the first phase of the direct current waveform having a first amplitude that provides the conduction block of the neural structure, wherein the first amplitude is a block threshold value for the neural structure;
delivering the first phase of the direct current waveform through the one or more electrodes to the neural structure for a first time to provide the conduction block;
providing a second phase of the direct current waveform from the waveform generator to the one or more electrodes, the second phase of the direct current waveform having a second amplitude less than the first amplitude but non-zero, wherein the second amplitude is a subthreshold value for the neural structure;
delivering the second phase of the direct current waveform through the one or more electrodes to the neural structure for a second time, after the first time, to maintain the conduction block of the primed neural structure; and
shutting off the second phase of the direct current waveform after the second time, wherein the recovery time of the primed neural structure is accelerated when the second phase of the direct current waveform is shut off compared to when only the first phase of the direct current waveform is delivered,
wherein the one or more electrodes are configured to be in electrical communication with the neural structure.
2 . The method of claim 1 , wherein the conduction block is a partial block.
3 . The method of claim 1 , wherein the one or more electrodes comprise a surface or transcutaneous electrode.
4 . The method of claim 1 , wherein the one or more electrodes reside in a cuff.
5 . The method of claim 1 , wherein the one or more electrodes comprise a percutaneous electrode.
6 . The method of claim 1 , wherein the one or more electrodes comprise at least one separated interface nerve electrode (SINE).
7 . The method of claim 1 , wherein a power required to deliver the first phase followed by the second phase of the direct current waveform is less than a power required to deliver the first phase of the direct current waveform alone over a same time period.
8 . The method of claim 1 , wherein the second time is greater than the first time.
9 . The method of claim 1 , wherein the first phase and the second phase of the direct current waveform have the same polarity.
10 . The method of claim 1 , where the first phase provides the conduction block of the neural structure within 1 second of delivery.
11 . A system comprising:
a waveform generator configured to provide only a direct current (DC) waveform having at least two phases to one or more electrodes, wherein the DC waveform comprises:
a first phase with a first amplitude that provides a conduction block of a neural structure within 1 second, wherein the first amplitude is a block threshold value for the neural structure; and
a second phase, after the first phase, with a second amplitude less than the first amplitude, but non-zero, wherein the second amplitude is a subthreshold value for the neural structure; and
one or more electrodes configured to be in electrical communication with the neural structure and to:
deliver the first phase for a first time to provide the conduction block of the neural structure; and
deliver the second phase for a second time, after the first time, to maintain the conduction block of the neural structure, wherein then the second phase is shut off after the second time, the recovery time of the neural structure is accelerated compared to when only the first phase is delivered.
12 . The system of claim 11 , wherein the one or more electrodes comprise a surface or transcutaneous electrode.
13 . The system of claim 11 , wherein the one or more electrodes comprise a subcutaneous electrode.
14 . The system of claim 11 , wherein the one or more electrodes comprise a percutaneous electrode.
15 . The system of claim 11 , wherein the one or more electrodes comprise at least one separated interface nerve electrode (SINE).
16 . The system of claim 11 , wherein the second time is greater than the first time.
17 . The system of claim 11 , wherein delivery of the first phase of the direct current waveform and the second phase of the direct current waveform for a time consumes less power than delivery of the first phase of the direct current waveform for the time.
18 . The system of claim 11 , wherein the conduction block is a partial block.
19 . The system of claim 11 , wherein the first phase and the second phase of the direct current waveform have the same polarity.