Cochlear implants

A cochlear implant uses a sound processor that's worn behind the ear. The processor takes sounds from outside the ear. It sends the sound signals to a receiver that's been put under the skin behind the ear. The receiver sends the signals to electrodes that have been put in the snail-shaped inner ear, called the cochlea. The signals activate the cochlear nerve, which sends the signals to the brain. The brain hears those signals as sounds. There are two styles of cochlear implant external processors. One type is a single unit worn off the ear that has a speech processor, microphone, magnet and transmitter in it (lower left). Another is the over-the-ear processor. The parts are in two pieces that are connected by a wire (upper left).