What is a cochlear implant?
A cochlear implant is an electronic medical device that replaces the function of the damaged inner ear.
Unlike hearing aids, cochlear implants don’t just amplify sounds. They mimic the natural hearing function of the inner ear through electronic stimulation.
The system has two parts
- The internal device – This is surgically implanted and placed behind the ear under the skin and the electrode array is inserted into the cochlea
- External sound processor – This is placed over the skin about 2-3 weeks post surgery and it connects with the internal device by a powerful magnet
Incoming soundsare processed into electrical signals and then transmitted directly to the hearing nerve, bypassing the damaged parts of the inner ear.
- A sound processor worn behind the ear or on the body, captures sound and turns it into digital code. The sound processor has a battery that powers the entire system.
- The sound processor transmits the digitally-coded sound through the coil on the outside of your head to the implant.
- The cochlear implant converts the digitally-coded sound into electrical impulses and sends them along the electrode array placed in the cochlea (the inner ear).
- The implant’s electrodes stimulate the cochlea’s hearing nerve, which then sends the impulses to the brain where they are interpreted as sound.
Who can benefit from cochlear Implant surgery
- Have severe to profound hearing loss in both ears
- Receive little or no benefit from hearing aids
- Score 50% or less on sentence recognition tests done by hearing professionals in the ear to be implanted
- Score 60% or less on sentence recognition tests done by hearing professionals in the non-implanted ear or in both ears with hearing aids
The ideal candidates for cochlear implant are
- Children who have congenital deafness and have not developed speech as a result of hearing loss (Pre-lingual) These children can develop good speech if surgery is done as early as possible preferably before 5 years of age
- Children or adults who loose their hearing later during life due to disease, ototoxic drugs or infections like meningitis (Post-lingual)