Computational analysis of neural stimulation thresholds for several charge-balanced biphasic waveforms: a case study

Abstract

Charge-balanced biphasic waveforms are commonly used in chronic neural stimulation, especially in the form of pseudo-monophasic waveforms, where the active phase is of much higher amplitude, and the other one is of low amplitude and longer duration, serving only for charge balancing. We analyzed the excitation thresholds for three such waveforms, varying their timing parameters. Their thresholds were compared to the threshold of the monophasic waveform having the same active pulse duration. The results show that pseudo-monophasic thresholds are considerably higher than those of monophasic waveform having the same pulse duration for the shorter pulse durations, but tend to equalize towards long pulses, where it becomes practically irrelevant whether the waveform is purely monophasic or pseudo-monophasic. This case study was performed by computational nerve modeling and simulation using SENN (Spatially Extended Nonlinear Node) nerve model.