The implants send the sounds through a processor and back to a transmitter that delivers the sounds through electrodes, which stimulate the auditory nerve. Scientists are working on producing smaller units that process signals faster, enhanced processing to improve the perception of speech and music, and fully implantable devices, which are expected in three to five years. Unlike hearing aids, implants are covered, at least in part, by most insurance companies. Their use in children has been controversial, and their success somewhat spotty. Generally, Niparko says, the younger the child is when implanted, the easier it is for him or her to learn to understand sounds and to speak.
Research shows that exposure to speech early in life is crucial to language development.
If the brain has no knowledge of sound, it can't immediately interpret sound information accurately. Three may not be as good as 18 months, and 18 months may not be as good as 12 months. That doesn't mean children who are older are never successful with implants. When a child is born deaf and doesn't get an implant for years, there is a language gap, he says. It's easier to backfill that gap if a child is younger.