Cochlear implants give a sensation of hearing if you are severely or profoundly deaf. A cochlear implant is an electronic device that is made up of two parts: the internal part and the external part and it works in a completely different way to your hearing aid.
The internal part is surgically implanted and includes a receiver with a magnet in the middle that is positioned under the skin behind and above your ear, and a set of electrodes, which is placed inside the cochlea (inner ear). The magnet is there to hold the external transmitter directly over the implanted receiver. The receiver picks up the signal from the transmitter coil on the outside of the skin and sends it to the electrodes inside the cochlea. The electrodes take over the job of the damaged cells in the cochlea and send electrical signals along the nerve of hearing to the brain. Your brain learns to recognise these signals as sounds.
The external parts consist of a microphone, a speech processor and a transmitter coil. The microphone picks up sounds from around you and converts them into electrical signals. The signal is then passed to the processor, which processes and adjusts the signal to suit your needs and sends it to the transmitter coil that is placed flat against the skin slightly behind your ear. This transmits the signal to the internal part (please see previous paragraph). The microphone and processor are normally positioned behind the ear,in a device that looks very much like a large hearing aid.