A Numerical Analysis Of The Electric Field Generated By A Nerve Cuff Electrode

We have developed a three dimensional finite element model of an unifascicular nerve and studied the effects of electrode configurations and the effects of tissue conductivities in and around the nerve trunk on the potential distribution due to a cuff electrode. From the potential distribution we can estimate the region of the nerve trunk where fibers of specific diameter are excited. Our results indicate that selective activation of the nerve fibers was affected by the anisotropy of the nerve trunk and the perineurium. Tripolar configuration with a smaller spacing between the anodes and the cathode, was more effective in confining the current to the superficial regions of the nerve trunk relative to a monopolar configuration and selectivity of exatation was further improved by steering the current with an anode located across the cathode.