Initial results from a model of ephaptic excitation in the electrically excited peripheral auditory nervous system

This article reports on a study performed to investigate the occurrence and effect of ephaptic excitation in electrical stimulation of the auditory system. The objective of the study was to quantify the influence of ephaptic excitation on nerve stimulation and determine whether it is a necessary factor in neuromodeling. It was shown with a simple model that ephaptic excitation could be important at stimulus intensities close to threshold. The results show that the contribution of ephaptic excitation is significant up to at least 6-7 dB above threshold. Cochlear implant patients normally have a small dynamic range (average of 7 dB), indicating that the ephaptic effect might be important in models of the implanted cochlea.