March 24, 2005 -- Most deaf kids learn to hear after getting cochlear implants. And they keep on hearing, a long-term study shows.
A cochlear implant isn't a hearing aid which amplifies sound. Part of the computerized device is implanted under the skin behind the ear -- with electrodes that go deep into the ear. The devices turn sound waves into electric signals that are passed to nerve fibers leading into the brain. They allow even profoundly deaf people to hear.
It's not an overnight cure. People have to learn how to make sense of the signals a cochlear implant gives to the brain. At first it sounds like a mechanical noise. But eventually the brain adapts and recognizes more normal speech sensations. This takes time and lots of work. And it's not cheap. The average cost, including surgery and rehabilitation, is $40,000.
Over the long haul, is it worth it? For kids the answer is yes, suggest Jan Haensel, MD, and colleagues at Germany's Aachen University Hospital. The researchers collected data on 16 kids who got cochlear implants 10 to 13 years ago. They report their findings in the March issue of Otolaryngology.
Best Results in Youngest Kids
Overall, Haensel's team found that 14 of 16 kids who got implants now say they can hear. Four of the kids learned to hear and speak well enough to enter mainstream schools. But six of the kids never learned to understand normal speech.
The kids in the German study were 3 to 12 years old when they got their implants. Those who never learned to understand normal speech got their implants latest. That's because there's a window of opportunity for children to get the maximum benefit from cochlear implants, says Douglas Mattox, MD, professor and chair of otolaryngology at Atlanta's Emory University.
"There is a window that closes after which the implant is of no value," Mattox tells WebMD. "That is sometime in childhood. Whether it is age 4 or 6 or 8 years we don't know, but clearly [getting implants] earlier is better."
Haensel's team says that their results led them to refuse to do implants on kids over the age of 6 years. That's anathema to Jane R. Madell, PhD, who bristles at the idea. Madell is co-director of The Beth Israel/New York Eye & Ear Cochlear Implant Center, and director of the hearing, speech, language, learning center at Beth Israel Medical in New York.
"I guarantee kids implanted at 6 or 8 or 10 won't do as well as those implanted at 10 months," Madell tells WebMD. "But they still will get outstanding benefit. That is not a reason not to do implants in older kids."
Mattox, too, says that doctors currently get better results than those reported by Haensel's team.
"This report understates, not overstates, the expected results of cochlear implants in children," he says. "In Atlanta, children implanted before age 3 are mainstreamed in school before they reach the middle years of primary school."
Next: What Are the Keys to Cochlear Implant Success?
Mattox, reflecting a surgeon's caution, says it's impossible to predict how well an individual patient will hear after getting a cochlear implant.
"We do need to communicate with patients to make sure their expectations are reasonable," he says. "This is not a brand new ear. But it is tremendously beneficial to many, many people. The exact results in a given patient are unpredictable. We do have adult patients who talk on the telephone the day after they get the implant. Some people don't achieve those levels, and we don't know why."
Madell says there's nothing wrong with high hopes -- providing children and their parents are willing to work hard for success.
"We expect outstanding results," she says. "I believe there is virtually nobody who doesn't do well with cochlear implants if they are managed appropriately."
Madell notes that cochlear implants in both ears give much better results than single-ear implants. Even so, she stresses proper management. That has three components:
- Fine-tuning. Madell's center sees each patient 10-12 times, making sure the implants are "mapped" to get the right frequency for each component of spoken language.
- Good therapy. Emphasizing listening to spoken language rather than lip reading or sign language.
- Involved parents. "Even more important is the need for a parent or caregiver who will participate in therapy and do it at home," Madell says. "Somebody needs to talk to this child every waking minute."