Worldwide, approximately one person in a thousand is born with hearing impairment. Almost an equal number of people born with hearing will develop deafness during their lifetime.
The cochlear implant is an electronic device which restores partial hearing to the severe or profoundly hearing impaired. Part of a cochlear implant is surgically implanted in the ear and part is worn externally like a hearing aid. However, a cochlear implant is not a hearing aid in the sense of making sound louder or clear. It is a medical device which bypasses damaged parts of the inner ear and electronically stimulates the nerve of hearing. Our implant center is currently using the latest Nucleus Contour cochlear implant system and the Advanced Bionics Hi Res 90K cochlear implant.
How Cochlear Implants Work
Cochlear implants are electronic devices that bypass the damaged hair cells and stimulate the hearing nerve directly. The cochlear implant system consists of internal and external parts. The microphone and speech processor are worn outside the body, like a hearing aid. A surgically implanted receiver provides a direct connection between the speech processor and electrodes. The electrical stimuli are sent inside the body to the implanted electrodes. The electrical signal stimulates the auditory nerve fibers, and the signal is then sent to the brain.
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Who is a Cochlear Implant Candidate?
The cochlear implant is designed for individuals who receive no significant benefit from hearing aids. Candidates are usually one year of age or older. The criteria for cochlear implant candidacy are as follows:
Children
Ages: 12 months to 24 months
Becoming a Cochlear Implant Patient
Becoming a cochlear implant patient involves a series of evaluations including otologic, audiologic, radiographic and psychological tests. An examination must be performed to assure that there is no active infection or other problem with the middle or inner ear that would preclude the surgical placement of the implant. An audiologist performs extensive hearing tests to determine the degree of hearing with and without a hearing aid. Special tests are also performed to evaluate the benefits from hearing aids. Special x-rays, usually computerized tomography (CT) scans, are taken to evaluate the condition of the inner ear bone.
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Cochlear Implant Surgery
Cochlear implant surgery is performed under general anesthesia. An incision is made behind the ear. The mastoid bone is opened, leading to the middle ear. The operation takes about three hours and the patient usually goes home the same day.
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Postoperative Care and Follow Up
About a month after surgery when the incision is healed, the patient returns for the first fitting of the external components. The audiologist uses a computer and special software to program the speech processor to the best listening strategy for the patient.
The audiologist along with the patient’s assistance will determine the appropriate levels of stimulation for each electrode and these levels will be used to make “maps” for the patient to hear with their implant. The audiologist and the patient together will develop a schedule of follow-up visits for fine-tuning of your speech processor. As the patient becomes more experienced with their cochlear implant, the follow-up visits will become less frequent and the patient will only need to be seen once or twice a year for adjustments.
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Severe-to-profound sensorineural hearing loss in both ears