Cochlear Implants

A cochlear implant bypasses missing or damaged sensory cells in the inner ear to directly stimulate the auditory nerve. The device includes an external microphone worn behind the ear, a sound processor, and transmitter. The transmitter delivers electrical stimulation to a receiver implanted beneath the skin, which relays the signals along an implanted electrode to the inner ear, or cochlea. Typically, eight electrodes are used to deliver eight different frequencies of sound. Since sounds heard through a cochlear implant do not recreate the subtleties of normal hearing, surgical implantation is followed by significant therapy to train users to interpret the sounds. Many users are eventually able to follow conversation unaided. Commercially available since the 1980s, by 2012, cochlear implants had been used by about 300,000 people worldwide. (1)


1. Semenov YR, Martinez-Monedero R, Niparko JK. Cochlear implants: clinical and societal outcomes. Otolaryngol Clin North Am. 2012 Oct;45(5):959-81. doi: 10.1016/j.otc.2012.06.003. Epub 2012 Jul 31. Review. PubMed PMID: 22980678.

Reviewed March 4, 2012
Lawrence Poree, MD, PhD
Member, International Neuromodulation Society
Professor, University of California School of Medicine, Department of Anesthesia, San Francisco CA, USA

Last Updated on Monday, November 22, 2021 11:04 AM