The Cochlear Implant is a device which when implanted into the inner ear, provides useful hearing to those with total or severe to profound sensory (inner ear) hearing loss.
It is not an ordinary hearing aid, but an electronic device that bypasses the damaged parts of the inner ear to stimulate the remaining auditory nerve fibres. Part of the cochlear implant is implanted under the skin in a surgical procedure.
How a Cochlear Implant works
With reference to the diagram on the right:
(a) Sounds enter the system through a small microphone attached behind the ear.
(b) The sound is sent from the microphone to the speech processor through a tiny cord that connects the two.
(c) The speech processor selects and codes the elements of sound that are most useful for understanding speech.
(d) These electronic codes are sent back through the cable to the transmitter.
(e) The transmitting coil, a plastic covered ring about 33mm in diameter, sends the codes across the skin to the receiver/stimulator.
(f) The receiver/stimulator contains a custom-designed integrated circuit that converts the codes into special electronic signals and sends them along the electrode array.
(g) The electrode array is a set of 22 tiny electrode bands, arranged in a row inside a piece of tapered flexible silicone tubing. Each electrode has a wire connecting it to the receiver/stimulator.
(h) The coded electronic signals are sent to specific electrodes, each of which has been separately programmed to deliver sounds that can vary in loudness and pitch. These electrodes then stimulate the appropriate hearing nerve fibres, which send the messages to the brain.
Frequently Asked Questions
Who should get a Cochlear Implant?
A cochlear implant may be considered for the following:
(a) Adults and children with a severe-to-profound or profound sensory hearing loss in both ears, who received limited benefit from hearing aids.
(b) Those who do not have any medical conditions that would prevent them from undergoing a surgical procedure.
(c) Those who have the support of friends and family.
(d) Those who want to be part of the hearing world.
(e) Children who will be enrolled into an education programme that stresses auditory and verbal language development.
(f) Children as young as one year of age may be implanted. It is usually said that the earlier the implantation, the better the outcome will be.
What are the benefits of having a Cochlear Implant?
The outcome varies with each individual and is influenced by:
- The age at which the hearing loss occurred
- How long it's been since the hearing loss occurred
- The integrity of the auditory nerve
- Motivation and emotional support from family and friends
- The amount of practice and training in the early stages of implant
- What are the follow-ups required after surgery?
The implant has to be programmed by the audiologist before it can work. Programming of the implant will be carried out 2 to 3 weeks after surgery, after which the implant needs to be programmed periodically to maximise the speech sounds that can be heard by the individual.
A period of (re)habilitation is also required, especially in children, to gain the maximum benefits from listening through the implant. Implanted children will be enrolled in therapy sessions in Listen and Talk Programme, where the Auditory-Verbal approach is adopted to help children develop speech and language.
What should my expectations be?
A Cochlear Implant may not be the right choice for everyone. An evaluation by an experienced cochlear implant team will help you to decide.
No Cochlear Implant is able to restore normal hearing completely. However, with the Cochlear Implant, adults can look forward to hearing sounds that may help them to carry on a conversation and participate in everyday life.
The outcome in children varies, but the ultimate objective is that children can develop speech and language. For further information, please do not hesitate to contact us for an appointment.