Pulsed wavelength-dependent laser stimulation of the inner ear.

Conventional cochlear implants electrically stimulate the auditory nerve to bypass non-functional hair cells. The present study investigates optical stimulation as alternative to replace cochlear function. Although pulsed laser light is known to excite the organ of Corti, the interaction sites of pulsed lasers with the cellular elements of the inner ear have not been clarified yet. So far, two possible mechanisms of stimulation were suggested: optoacoustic stimulation of surviving hair cells and direct stimulation of auditory nerve fibres. In order to find the most effective stimulation with the least side effects the relation between cochlear compound action potential (CAP) and wavelength and pulse energy of optical stimulation were investigated.