Nerve fiber stimulation using symmetrical biphasic waveform applied

Abstract

Nerve fiber stimulation is disclosed using a symmetrical biphasic waveform applied through plural active electrodes to increase the activity of the nerve fibers then selected for stimulation. Bi-phased pulse pairs are repeatedly symmetrically generated and applied to the nerve fibers to be stimulated with the first pulse of each pulse pair being a positive polarity pulse applied through a first electrode to cause the nerve fibers to be set into the refractory period and with the second pulse of each pulse pair being a negative polarity pulse applied through the first electrode to occur substantially at the end of the refractory period for the nerve fibers then to be stimulated to thereby excite those nerve fibers. The pulse pairs are also applied in inverted polarity through a second electrode with the inverted second pulse thus resulting in an applied positive pulse at the second electrode to cause the nerve fibers to be stimulated to be set into the refractory period and with the inverted first pulse of the succeeding pulse pair resulting in an applied negative pulse at the second electrode occurring substantially at the end of the refractory period for the particular nerve fibers to be stimulated to thereby excite those nerve fibers. Plural channels having dual active electrodes can be provided with applied bi-phased pulses being timewise offset from one another to maintain isolation between channels.