What is a cochlear implant?
A Cochlear implant is an electronic device made up of two parts: an implanted component that is inserted during an operation, and external components worn on the head or body like a hearing aid. Cochlear implants provide a sensation of hearing for people who cannot obtain useful benefit from conventional hearing aids. Because the implant bypasses the damaged hair cells in the inner ear and stimulates the nerve of hearing directly. They are appropriate for both adults and children with severe to profound hearing impairment in both ears.
(Diagrams courtesy of MED-EL, Cochlear and Advanced Bionics)
Cochlear implantation can greatly improve quality of life; however the signal received via the implant is not normal hearing and therefore patients require time and training to become accustomed to it. Rehabilitation is required after implantation to promote optimal benefit from the device, especially in the case of young children who may never have heard before.
The cochlear implant electrode
An array of several electrodes is inserted into the cochlea. This delivers electrical pulses directly to the hearing nerve. Then the nerve carries the information to the brain, where it is interpreted as sound.
The internal part of the implant consists of a receiver-stimulator package and an electrode array. The receiver-stimulator package contains electronic components which pick up the information from the transmitting coil worn on the head. Then this information delivered to the electrodes on the electrode array, in the form of pulses of electricity.
The speech processor picks out the useful features of the incoming sound, and converts it into a digital signal. The speech processor is connected to the internal device by means of a coil/cable and held on with a magnet.
The type of processor the patient uses depends on the cochlear implant system they have and their own preference.