Impedance Sensing

In cochlear implant (CI) recipients, positioning the electrode array close to the cochlea’s inner wall, housing the auditory nerve, results in better hearing outcomes. This study investigates the usability of electrical impedance recordings at the CI’s electrode contacts for predicting electrode distances to the inner wall. We introduce a protocol for “three-point impedances” in which bipolar impedances are recorded in response to monopolar stimulation at a neighboring electrode. Using an experimental setup with cadaveric human temporal bones and a lumped-element model of an implanted CI, we show that three-point and existing four-point impedances are promising measures to predict electrode placement. read more