Abstract
Cochlear implant is a device that provides electrical stimulation directly to the cochlea. Stimulation pulses emitted from the inserted electrode is transmitted to the brain through the auditory nerves in the cochlea. Some patients with significant hearin g loss still have residual hearing for low frequencies. An attempt has been made to amplify acoustic sound at low frequencies with a conventional hearing aid and to apply electrical stimulation for the middle and high frequencies with the cochlear implant. This device is called the electric-acoustic stimulation (EAS). In this study, the electrode for the electric-acoustic stimulation was optimized by using a three dimensional finite-element model of the human cochlea. Dynamic behavior of the basilar membrane (BM) and the cochlear fluid caused by the vibration of the stapes footplate were analyzed. The effect of the Young's modulus of the electrode on the vibration of the BM was examined by modeling the electrode in the cochlea model. The results suggest that BM has large amplitude at low frequencies and the residual hearing is preserved by reducing the stiffness of the base of the electrode.
