A cochlear implant is an artificial device that helps one hear by producing useful hearing sensations through electrical stimulation of nerves in the inner ear. It replaces the function of the haircells that have been damaged in those individuals with severe-profound hearing impairment.

The cochlear implant is composed of two main components. One is the receiver-stimulator (package and electrode array) and secondly, the speech processor and headset. The receiver-stimulator contains the electronic circuits that send the flow of electrical pulse to the inner ear. The package also contains an antenna that receives a radio frequency signal from the magnetic coil that holds the external magnet into place.

The electrode array is inserted by the surgeon into the cochlea. The receiver-stimulator and magnet are placed permanently into the mastoid bone under the skin.

The external portion of the implant system has two parts, a headset and speech processor. One portion of the headset contains a magnet/coil which adheres to the outside of the skin opposite the internal portion placed in the temporal bone. Attached to the coil is the microphone which is worn behind the ear.

A body worn processor (see below) is often worn in a shirt pocket, belt or a harness type device. An ear level processor is worn behind the ear similar to a behind-the-ear hearing aid. The speech processor and microphone are together as one unit attached to the coil by a cord.

The speech processor is programmed about 4-6 weeks after surgery.