3-D electrical model of a neuroprosthesis stimulator based on the concept of stimulus router system

Lost sensory or motor functions can be restored using electrical neural prostheses (NP), which include surface NPs, implanted or subcutaneous NPs and the more recentStimulus Router System (SRS). The latter type of NP outperforms the other types in its selective excitation and least invasiveness.In each case, the achieved performance depends on a multitude of design factors among which the electrical excitation waveformshape, frequency, duration of pulses, configuration of electrodes,number of intervals, thermal conditions and electrode material. To investigate the effects of these parameters on the distributionof electric current inside biological tissues, numerical modeling can be employed as a powerful computational method. Inthis work, a 3-D electrical model is proposed to simulate the distribution of electric potentials and currents in the adulthuman forearm for an SRS NP. At the frequency of 50Hzand for a 5mA square waveform current source, results of our simulation show that the ratio of the current flowing insidethe implanted conductor to the current applied to the cathodal electrode (capture ratio) is approximately equal to 2:02%. Thisvalue is close to the experimentally reported result for the SRS, 1:9%, giving an absolute error of 0:12% and relative error of 6:3%.

3-D electrical model of a neuroprosthesis stimulator based on the concept of stimulus router system Keywords:

SRS , Simulation , COMSOL Multiphysics , Neuroprosthesis