Cochlear implants

© 1998 Edward Arnold. This is a preprint of a chapter from S. R. Mawson, H. Ludman & T. Wright (Eds.), Diseases of the ear (pp. 143-163). London: Edward Arnold. Reproduced with permission of Hodder Education.A cochlear implant is a device to restore some hearing in severely-to-profoundly or profoundly deaf people when their organ of Corti has not developed or is destroyed by disease or injury to such an extent no useful hearing can be obtained with a hearing aid When the organ of Corti is absent, sound vibrations cannot be transduced into temporo-spatial patterns of action potentials along the auditory nerve for the coding of frequency and intensity, and a hearing aid which amplifies sound is of little or no use. A cochlear implant should reproduce the patterns of action potentials required for the coding of sound to such an extent that speech and environmental sounds can be recognised and understood