[Determinants of the effectiveness of cochlear implants: I. Placement in the cochlea]

The present paper introduces a registration method for the electrical field produced by a cochlear implant in the scala tympani in vitro. It was possible to determine the electrical potentials with high spatial resolution using an additional recording electrode. The results indicate that the efficacy of the stimulation by the more apical electrodes is higher than by the more basal ones. The reason is the decreasing cross-sectional area of the scala tympani, which represents a decreasing shunt between the stimulation electrodes.