Sound processing for cochlear implants

Cochlear implants are devices designed to provide a measure of hearing to the deaf. Most deaf individuals have lost the ability to translate sound into the patterns of electric activity normally present on the 30000 fibers of the auditory nerve. Because these patterns of activity are the inputs to the brain that result in sound sensation, cochlear implants deliver electric stimuli to these fibers in an attempt to artificially elicit patterns of spike activity that mimic the patterns present in a normal-hearing ear. We introduce cochlear implants by describing the signal processing used by current devices. Measurements of patient performance in quiet and in noise are used to demonstrate the limitations of today's devices and to introduce the avenues of current research that show promise for improving the performance of these devices.