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Cochlear Implants
Cochlear implants are small, electronic devices that can be surgically implanted to enable profoundly deaf children and adults who are not helped by traditional hearing aids to hear better. The May 19, 2004, issue of JAMA includes an article about cochlear implantation in children, and the May 2004 issue of the Archives of Otolaryngology Head & Neck Surgery is a theme issue devoted to this topic.
HEARING
- Sound waves funneled into the ear cause the tympanic membrane (eardrum) to vibrate.
- These vibrations are transmitted across a bridge formed by 3 small bones to the cochlea of the inner ear.
- The fluid-filled cochlea contains hair cells that sense vibrations transmitted through the fluid.
- The hair cells trigger impulses in the auditory (hearing) nerve that transmit to the brain where they are interpreted as sound.
Most profound deafness is sensorineural—there is damage to the sensitive and vulnerable hair cells in the cochlea so that vibrations in the cochlea cannot be transmitted. Cochlear implants can restore hearing by bypassing the hair cells and stimulating the auditory nerve directly.
AFTER SURGERY
- After the patient recovers from surgery for about a month, the speech processor is placed and then adjusted as hearing improves in a process called mapping. As hearing gets better, further adjustments are made over time.
- Training with speech therapists or a teacher of the hearing-impaired will help patients learn how to use the cochlear implant. Children in their formative years need to be taught to understand new sounds and their meanings and to translate them into speech and language.
FOR MORE INFORMATION
INFORM YOURSELF
To find this and other JAMA Patient Pages, go to the Patient Page link on JAMA's Web site at http://www.jama.com. A Patient Page on adult hearing loss was published in the April 16, 2003, issue.
Sources: Cochlear Implant Association, Inc, National Institute on Deafness and Other Communication Disorders, American Speech-Language-Hearing Association
The JAMA Patient Page is a public service of JAMA. The information and recommendations
appearing on this page are appropriate in most instances, but they are not a substitute for medical diagnosis. For specific information concerning your personal medical condition, JAMA suggests that you consult your physician. This page may be photocopied noncommercially by physicians and other health care professionals to share with patients. Any other print or online reproduction is subject to AMA approval. To purchase bulk reprints, call 718/946-7424.
TOPIC: HEARING
Sharon Parmet, MS, Writer;
Cassio Lynm, MA, Illustrator;
Richard M. Glass, MD, Editor
JAMA. 2004;291:2398.
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