Method to treat pain through electrical stimulation of nerves
Methods of treating pain are disclosed, wherein a non-pulsed, low-frequency electrical current is applied to the nerve carrying the pain signals in order to suppress transmission of those signals. In desired embodiments, the current is applied in a direction transverse to the nerve axis. Such currents have been found not to induce motor-neuron recruitment, meaning these methods can treat pain without causing muscle spasm or other muscular responses. A cuff for applying such a current transverse to the nerve axis is also disclosed.
1. A method for treatment of pain, comprising:
generating, by a power supply device, a non-pulsed electrical current comprising a frequency between 10 Hz and 2000 Hz and a rise time from 0 to a peak amplitude of at least 10 μs;
supplying the non-pulsed electrical current to at least two electrodes at diametrically opposed locations about the peripheral nerve;
applying, by the at least two electrodes, the non-pulsed electrical current through the peripheral nerve in a direction substantially transverse to a longitudinal axis of the peripheral nerve; and
inhibiting conduction of C-fibers in the peripheral nerve based on the application of the non-pulsed electrical current to prevent the transmission of pain signals,
wherein motor nerve fibers and higher-sensory nerve fibers in the peripheral nerve are not substantially activated based on the application of the non-pulsed electrical current.
2. The method of claim 1 , wherein the frequency is between 10 Hz and 500 Hz.
3. The method of claim 1 , wherein the frequency is between 10 Hz and 150 Hz.
4. The method of claim 1 , wherein the frequency is about 130 Hz.
5. The method of claim 1 , wherein the non-pulsed electrical current comprises a charge-balanced waveform.
6. The method of claim 1 , wherein the non-pulsed electrical current comprises an analog waveform that exhibits a rise time between neutral and peak amplitude of at least 10 μs.
7. The method of claim 6 , wherein the rise time is at least 20 μs.
8. The method of claim 6 , wherein the analog waveform comprises a sinusoid.
9. The method of claim 6 , wherein the analog waveform comprises a declining segment that exhibits an instantaneous step from peak amplitude to neutral.
10. The method of claim 1 , wherein the non-pulsed electrical current comprises a digital waveform comprising a series of discrete steps whose sum approximates an analog waveform having a rise time between neutral and peak amplitude of at least 10 μs.
11. The method of claim 10 , wherein the frequency is between 10 and 20 Hz or at least 40 Hz.
12. The method of claim 10 , wherein the rise time is at least 1000 μs.
13. The method of claim 10 , wherein the digital waveform approximates a sinusoid.
14. The method of claim 1 , wherein the non-pulsed electrical current comprises an amplitude between 0.4 mA and 5 mA.
15. The method of claim 1 , further comprising simultaneously applying a second current, independent from the non-pulsed electrical current, through the peripheral nerve to inhibit or suppress transmission of motor signals through motor fibers in the peripheral nerve.
16. The method of claim 1 , wherein the non-pulsed electrical current consisting of one or more non-pulsed electrical waveforms.
17. The method of claim 1 , wherein the non-pulsed electrical current comprises a triangular waveform.
18. The method of claim 1 , wherein the non-pulsed electrical current comprises a trapezoidal waveform.
19. The method of claim 1 , wherein the non-pulsed electrical current comprises at least one of a logarithmic waveform and an exponential waveform.