Measurement of electrical fields generated in physiological tissues by cochlear implants

Electric potential field distribution induced in the physiological tissues by bipolar current pulses, generated by a cochlear implant electrode array, was calculated by mathematical modeling the electrical properties of the human cochlea and of the electrode array, using a finite element method. At the same time it was planned an experimental setup to compare simulated data to the potential distributions measured in-vitro using a saline solution bath. Theoretical measurements were done under different stimulation conditions, i.e., by considering different electrode shapes and configurations, stimulus intensities, pulse stimulation rates, and pulse durations. All these parameters were found to affect the resulting field potentials. Preliminary results of this study provide a deeper knowledge of the relationship between the stimulation parameters and the actually delivered electric field, which is crucial to develop more efficient and spatially focused excitations of cochlear neural tissues