What Are Cochlear Implants?

A cochlear implant (CI) is an implantable medical device designed to provide sound detection and speech recognition for individuals with a severe to profound hearing loss. In contrast to a hearing aid, a cochlear implant bypasses the damaged part of the ear by providing electrical stimulation to the surviving auditory nerve fibers in the cochlea.  The sound that is heard is no longer acoustical sound, but is electrical sound.  In many cases, the cochlear implant provides improved understanding of speech and better overall hearing ability. 

A cochlear implant consists of an implanted electrode array and an external sound/speech processing unit.  Sounds are picked up by a microphone and transmitted to the speech processor.  The speech processor appearance is similar to a hearing aid or is a body unit (which is worn on a belt or in a pocket).  The sounds are converted to electrical information, which is delivered through the skin via a magnetic transmitting coil to the electrode array.  The electrodes send the sound information signals to the hearing nerve, which then relays it to the brain, where the sound is finally interpreted.  As with hearing aids, a battery powers the speech processing unit.