WHAT is a cochlear implant? If a child is born deaf, can he or she undergo the implant or is there an age limit to the procedure? Can they have normal hearing?

A cochlear implant is an electronic device that is surgically implanted under the skin behind the ear to provide useful sound or a sense of hearing to a person who is severely hard of hearing or profoundly deaf. It is not a bionic ear.

A cochlear implant receives external sound through a hearing device placed on the skin surface of the head. The sound is processed and converted into electrical impulses and introduced into the inner ear (cochlea) via tiny electrodes.

The impulses are then received by the auditory nerves and the signal is sent to the brain as a sound but it is not the same as normal hearing.

Children who are born deaf will need proper assessment to determine to cause of deafness.

Any child with severe to profound sensory neural hearing loss and who has failed with conventional hearing aids, can go for cochlea implant provided the child has intact auditory nerves and a normal anatomy of the cochlea (inner ear).

The prelingual stage is when the child has not learned to speak while postlingual is one who can speak.

Children with prelingual deafness or are born deaf must get some form of hearing aid before they are 5-6. The earlier hearing is established, the earlier they will be able to learn to speak.

In the United States, research shows that congenitally deaf children who receive cochlear implants at less than 2 years old have better success than those who get the implants at a later age.

For those with postlingual deafness, it can be of any age, as long as they are severe to profound sensoryneural deafness with failed trial of conventional hearing aid.

The younger a child is, the higher the learning capability of the brain. In the US, a child will be a candidate at 2 years of age.

Adults who have lost their hearing due to disease, accident or age are good candidates as the brain will recognise sound better and cochlea implants will prove more rewarding.

A cochlea implant does not give a person normal hearing but helps them perceive sound and regain some comprehension of speech.

Those who have lost their hearing (short term) as adults find cochlear implants useful. If an individual has been deaf for a long period of time, the brain may use the area of the brain for hearing for other functions.

If such a person receives a cochlear implant, the sounds can be very disorienting and the brain often will struggle to readapt to sound.

Dr Balachandran Appoo is an ENT head neck surgeon at Tropicana Medical Centre