What is a Cochlear Implant?
A cochlear implant provides sound sensations to the auditory nerve through vibrations in the inner ear, which help the wearer to make sense of the sounds in his environment. Initially, the wearer hears a robotic, metallic sound, but as he adapts to the sound and is trained to listen, his sound recognition and speech perception abilities improve.
Who Qualifies for a Cochlear Implant?
Currently, over 219,000 adults and children worldwide have cochlear implants. Implantation criteria are continually changing as technology evolves and more information about cochlear implants become available.
A cochlear implant effectively destroys any residual hearing that a person may have left in her inner ear. Consequently, only children with severe to profound hearing losses are considered for cochlear implants. A cochlear implant team consists of several professionals, such as an otolaryngologist, audiologist, psychologist, speech-language pathologist, and the parents of the hearing impaired child.
To determine candidacy for an implant, the team asks questions, such as:
- What is the degree of hearing loss? Should be severe to profound.
- Did the child show progress in speech and language development with conventional hearing aids? Poor progress is an indicator for candidacy.
- How old is the child? FDA regulations allow one type of implant from 12 months. The younger a child is during implantation, the more benefit she can derive from listening to sound during this critical period for language acquisition.
- Does the child have an adequate support system for ongoing therapy? A child with cochlear implants needs intensive therapy for a couple of years.
- Are there abnormalities in the inner ear or auditory nerve? It might be impossible to insert a cochlear implant into a deformed inner ear.
How Does a Cochlear Implant Work?
During cochlear implant surgery, an electrode is inserted into the inner ear of a child with severe to profound hearing loss. This electrode takes over the function of the inner ear and stimulates the auditory nerve electronically. The external parts of a cochlear implant are worn behind the ear or in a pocket pouch or harness on the body and have the following components:
- A microphone – picks up sounds from the environment;
- A speech processor – puts sounds from the microphone through a selection and arrangement process;
- A transmitter and receiver – transforms sounds from the speech processor to electrical impulses that are sent to the electrodes in the inner ear.
It is important to understand that a cochlear implant does not restore normal hearing, but gives a hearing impaired person an electrical representation of sound, which can help him to understand speech and other sounds in his environment.
What Happens After Surgery?
After a surgeon has inserted the electrodes in a child’s inner ear, there is usually a four to six weeks waiting period before the cochlear implant is switched on for the first time. For the child with the hearing loss, the first sounds heard may sound meaningless and even unreal. The first session is the beginning of a long journey in programming and fine-tuning the components of the cochlear implant for optimal hearing.
In addition to this fine-tuning process, intensive auditory training and speech-language therapy is commenced as soon as possible, to help the child to derive maximum benefit from her implant. Although cochlear implants are not a magical cure for deafness, it has the potential to change the life of a hearing impaired child dramatically.