Cochlear Implant

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How it works

In a normal ear, sounds are transmitted through the air, causing the eardrum and then the ossicles (middle ear bones) to vibrate. This sends a vibratory wave into the cochlea (inner ear). These waves are then converted by the cochlea into electrical signals, which are sent along the auditory nerve to the brain.

A deaf person does not have a functioning inner ear. A cochlear implant attempts to replace the function of the inner ear by transforming mechanical energy (sound) into electrical energy, which can then be used to stimulate the cochlear nerve (the nerve for hearing), sending "sound" signals to the brain.

Most cochlear implants operate using several similar components. Sound is picked up by a microphone worn near the ear. This sound is then transmitted to a speech processor worn on the body, usually on a belt. The sound is then analyzed and converted into electrical signals -- which are transmitted to a surgically implanted receiver behind the ear. This receiver then sends the signal through an electrode array (wire) into the inner ear, where the electrical impulses are transmitted to the brain.