Kids do well with two cochlear implants: study

Deaf children who already had one cochlear implant had improvements in speech, hearing and related quality of life measures after a second was implanted in the other ear, researchers from the Netherlands reported this week.

And the degree of improvement didn't depend on how old kids were when they got their second implant, according to the study, published in the Archives of Otolaryngology - Head & Neck Surgery.

An improved quality of life after a second implant "is not surprising," said Betty Loy, who studies deafness and cochlear implants at the University of Texas Southwestern Medical Center in Dallas.

"I definitely would expect that to improve over time as the brain adjusts to that second implant. You're going to get better and better and better at doing all the things that bilateral hearing allows you to do," added Loy, who was not involved in the new study.

Cochlear implants transmit sound directly to the auditory nerve. Getting an implant requires surgery on the ear, and costs of the procedure and follow-up care can exceed $50,000. There's also the possibility of complications from infection or damage to the device - but those are relatively rare.

What a cochlear implant is A cochlear implant is a device that helps some deaf people hear. A surgeon puts part of the implant under the skin behind the ear and inside the inner ear. The implant has four parts:

The headpiece is worn behind the ear. Magnets hold it in place over the parts that are under the skin. It has a microphone that picks up sounds from the environment. A transmitter sends the sounds to the speech processor.
The speech processor is worn on the body. It takes sounds from the transmitter and changes them into electrical signals. Then it sends the signals to the receiver.
The receiver is placed under the skin behind one ear.
A wire from the receiver goes to the electrodes.
A doctor puts the electrodes in the cochlea. The electrodes take signals from the receiver and send them to the brain.

Because of the costs and risks, Loy said that doctors were initially hesitant to give young kids cochlear implants in both ears. But over time, she added, that trend has changed in the United States, and studies have shown that deaf children with two implants do better on hearing tests than those with a single implant.

Recently, Canadian researchers also provided reassuring news on cochlear implants, reporting that only a small fraction of children they operated on in the last 20 years had technical problems with their cochlear implants and needed new ones (see Reuters Health story of December 21, 2011.)

Who is a candidate for a cochlear implant?