Implant Lets Deaf Children Enter World of Hearing

Congenitally deaf children who would otherwise be condemned to a world of silence are hearing for the first time with a system that electronically provides what their ears cannot.

“The reason these children are deaf is because hair cells in the inner ear are not transmitting vibrations into nerve impulses,” said Los Angeles ear specialist William House, inventor of the cochlear implant.

A portion of the system is surgically placed deep within the inner labyrinth of the ear and serves as part of a four-prong system. It brings hearing to children who are either born deaf or developed hearing impairments from meningitis or other illnesses.

Nerve Stimulated

House said the system electronically stimulates the auditory nerve, causing the brain to perceive the impulses as the varied and integrated sounds recognized as speech, music and just plain old noise.

Seven research centers across the country are testing the device that so far has shown only a 1% failure rate in the 125 children who have received the electronic hearing system since 1984.

The implant has been approved by the Food and Drug Administration for use in scientific testing but is not available for deaf children who are not part of a scientific research project, House said.

“In the cases that failed, the inner ear did not have enough nerve endings to be stimulated,” House said of the process required to bring hearing to the deaf.

Metal Disk Implanted

The implanted portion of the system is a small metal disk that acts as a receiver for electronic impulses sent by the transmitter, a device that looks like a small pocket radio and can be tucked away in a pocket.

The transmitter, which has a highly sensitive microphone, picks up sounds and sends the impulses through a device much like an ordinary hearing aid.

The ear specialist said electronic impulses transmitted to the receiver are relayed to the brain as fast as sound impulses are transmitted to the brain by the normal ear.

Before the system’s development, “sign language was the only way these children were able to communicate,” House said.

A similar device has been available to adults for nearly two decades, but that version was described as inappropriate for children, especially those as young as 2, because of its size, he said.

“There are still a lot of refinements we’d like to make to improve the implant for children,” said House, who serves as co-director of the House Ear Institute in Los Angeles and who designed a similar system for adults.

“We’re developing devices that are even more compact and have better sound fidelity,” he said.

House describes the sound children heard by way of the implant as like “a radio not quite tuned in.”

He said that with the help of lip-reading, the children are learning to speak and communicate with others, a factor aiding in their transition from schools for the deaf to classrooms for children with normal hearing.

Device Has Critics

However, the electronic hearing system is not without its critics.

House said there are some scientists who have told him that the answers to childhood deafness will not be found through electronics, but through animal research.

But he added: “Those scientists will spend the next three generations working with guinea pigs, and deaf people will still be deaf.”

One in every 1,000 children in the United States is born deaf each year, and three in every 1,000 are born with hearing impairments, House said.