Question: How do cochlear implants work?

Rebecca Dewey answered on 16 Jun 2015:

A cochlear implant has a microphone that picks up sounds. It then converts these sounds into electrical signals (like in recording equipment). The electrical signals are transmitted to electrodes implanted in the inner ear. Modern cochlear implants usually have about 22 electrodes in the inner ear. This means that the person can only hear 22 distinct frequencies of sound, whereas our ears can hear thousands and thousands of distinct frequencies. These electrodes stimulate the hearing nerve, which carries nerve impulses to the brain.

So rather than being able to hear normal speech, people with a cochlear implant can only hear a mechanical/robotic sounding version of speech. They have to learn how to use this new sound to understand the world around them. We tend to talk about a cochlear implant “partially restoring hearing” rather than curing deafness or completely making someone hearing again because it is really not the same yet.