Influence of stimulus waveforms of high-frequency electrical current on nerve conduction block

The aim of this study was to determine the effect of monophasic, biphasic symmetric, and biphasic asymmetric balanced rectangular stimulus waveforms utilized in high-frequency electrical conduction block of nerve fibers. From the animal studies, we found that blocking stimulus with monophasic or biphasic asymmetric waveform at varied blocking current amplitudes showed better blocking effect, which can manipulate the maximal available torque up to 99%. However, the blocking effect of biphasic symmetric waveform only had up to 73%. In muscle fatigue tests, the reactive torque resulted from biphasic symmetric stimulus exhibited a rapid decreasing fatigue curve when compared to the curves induced by other tested waveforms. All those results demonstrated that the stimulus waveform was an important factor affected the nerve blocking efficiency and muscle fatigue pattern.