The cochlear implant is an electronic device which restores hearing to the totally deaf. Part of a cochlear implant is surgically implanted in the ear (temporal bone) and part is worn externally like a hearing aid. It is a medical device which bypasses damaged parts of the inner ear and electronically stimulates the nerve of hearing.
Normal Hearing:
The ear is divided into three parts: external ear, middle ear, and inner ear. Each part performs an important function in the process of hearing. Sound travels along the ear canal of the external ear and causes the ear drum to vibrate. The three small bones of the middle ear (malleus, incus and stapes) conduct this vibration from the ear drum to the cochlear or auditory chamber of the inner ear. Fluid waves in the cochlear, initiated by movement of the three small ear bones, stimulate the more than sixteen thousand delicate hearing cells (hair cells). Movement of these hair cells generates an electrical current in the auditory nerve. This current is transmitted through various complicated interconnections in the brain stem to the part action of brain that recognizes these electrical stimulations as sound.
How Cochlear Implant Works:
Cochlear Implants are designed to bypass the hair cells which are not functioning and provide stimulation directly to the auditory nerve. Cochlear implant systems consist of a microphone, a signal processor, a signal coupler (transmitter and receiver) and one or more electrodes that are implanted in the cochlea.
The microphone and signal processor are worn outside the body, like a hearing aid and the receiver and the electrode will be placed inside surgically, It won’t be visible after the surgery. The electrical stimuli are sent inside the body to the implanted electrodes. The electrical signals stimulate the auditory nerve fibers and the signal is then sent to the brain.
Who is a Cochlear Implant Candidate?
The cochlear implant is designed only for individuals who receive little or no benefit from hearing aids. Becoming a cochlear implantee involves an evaluation, including otologic, audiologic, radiographic and psychological tests:
Ear (Otologic) Evaluation
An examination must be performed to assure there is no active infection or other problem.
Hearing (Audiologic) Evaluation:
Extensive hearing tests must be performed to determine the degree of hearing with and without a hearing aid.
Imaging (Radiographic) Evaluation:
CT & MRI are taken to evaluate the condition of the inner ear bone and auditory nerve.
Neuro Psychological Evaluation:
Psychological evaluation is required for some cochlear implant children.
Cochlear Implant Surgery:
Cochlear implant surgery is performed under general anaesthesia. The operation takes from 2 to 3 hours depending on the specific cochlear implant being used. The hospital stay varies from one night to several days, depending on the device used and patient’s needs.
Postoperative Care, Training and Follow-up:
The patient returns to the implant clinic two to three weeks following surgery and is fitted with the external portions of the device (signal processor, microphone and transmitter). Cochlear implant programs differ in the amount of time required to fit the device and the amount of training provided. In addition, patients are usually required to continue returning to the clinic at regular interval for check-up and assessment.
What to Expect From a Cochlear Implant:
Cochlear implant provides near to normal hearing to the hearing impaired who gets limited or no benefit from usual hearing aid. The majority who receive a cochlear implant are able to learn speech and language and communicate like any other normal individual.
Results vary for different individuals, depending on factors such as age at time of deafness, age at implant surgery, duration of deafness, status of the remaining auditory nerve fibers, training, etc.
Cost of Cochlear Implant:
A cochlear implant is considerably more expensive than a hearing aid. Total costs (evaluation, surgery, device, rehabilitation may range from about 8,50,000 Rs to 21,50,000Rs for one ear.
N8 Sound Processor:
Cochlear have developed the Nucleus 8 Sound Processor (CP1110). The Nucleus® 8 Sound Processor is the world’s smallest and lightest behind-the-ear cochlear implant sound processor, delivering smarter hearing performance technology which can automatically and seamlessly adjust to patient’s listening environment. In addition, it’s ready for next generation Bluetooth® LE Audio technology, designed to help your patients engage and connect with life.
Introducing the Nucleus® 8 Sound Processor*, designed to:
• Provide the comfort and discretion as the world’s smallest BTE sound processor1
• Help patients engage and connect with life
• Enable better hearing in noisy situations2
• Compatible with Cochlear’s most reliable implants on the market3
Dr. Shiva Prasad Boddupally
Chief Audiologist & Clinical Specialist in Cochlear Implants
KIMS Hospital, Secunderabad
Shravya Speech and Hearing Center, Hyderabad
Shravani ENT Hospital, Kakinada