The University of Southampton

What is a cochlear implant?

  • Cochlear Implant User

    A cochlear implant is an electronic medical device that replaces the function of damaged inner ear hair cells.


  • The aim of a cochlear implant is to provide the recipient with access to the range of sounds that are important for hearing speech.


  • A cochlear implant does not amplify sound – it bypasses the damaged hearing system and stimulates the auditory nerve directly.



Why not use a hearing aid?

  • Hearing aids amplify sound via the normal hearing pathway.


Hearing Aid
Hearing Aid
  • For severe/profound hearing loss, the normal hearing pathway is damaged so amplification has little benefit.  Hearing aids will make the sound louder but not clearer.


  • Hearing aids cannot make high pitched sounds loud enough for a severe profound hearing loss.





The components of a cochlear implant

All current cochlear implants share the same basic components:

components of a cochlear implant

Please click on the tabs below to find out about the internal and external parts:

Internal Component (Implant)External Component (Speech Processor)

The internal component is inserted by a surgeon when the patient is under general anaesthetic. It consists of two parts:

1 – The receiver / stimulator package that sits underneath the skin and connects to the external speech processor via a magnet. It communicates with the external speech processor via FM signals.

2 – The electrode array is a cord of evenly spaced electrodes (contact points) which has been inserted inside the cochlea.

The external component consists of three parts:

1 – The microphones that collect the sound from the environment,

2 – The speech processor which converts the sound into a digital signal,

3 – The transmitting coil or headpiece that relays the information across the skin to the internal implant via an FM signal.

Key concepts

  1. What is a cochlear implant?
  2. How does it work?
  3. Who should have a cochlear implant?
  4. What does a cochlear implant sound like?
  5. Who manufactures cochlear implants?