For hearing-impaired people, the cochlear implant (CI) opens the way to the world of sound.

An electrode carrier implanted in the cochlea, in conjunction with a speech processor worn over the ear, helps deafened people re-gain their hearing capabilities to a large extent. Microphones integrated in the speech processor pick up the sound and convert it into electrical impulses. These signals are relayed via a magnetic coil worn on the head to the implanted electrodes in contact with the auditory nerve and recognised as sounds and speech in the brain. If the auditory nerve is damaged, which is the case in less than 5% of all persons with a hearing impairment, a CI makes no sense. Since hearing does not automatically equate to understanding, professional hearing training is needed in the early years to help children born deaf (who have been provided with CI in time to acquire language) in the same way as children with normal hearing.

Even adults who suffer late-onset deafness need time and intensive hearing training in order to re-learn how to hear.