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September 13, 2005

Breaking the silence

From: Los Angeles Daily News, CA - Sep 13, 2005

Pediatric cochlear implants reconnect deaf children with the world around them

Emanual Parker, Staff Writer

A milestone in the battle against childhood deafness occurred 25 years ago last month with the first pediatric cochlear implant, a device that helps children who cannot benefit from hearing aids to regain some hearing.

Dr. William House developed the device in the 1960s at the House Ear Institute in Los Angeles and successfully implanted them in adults. In 1981, he implanted one in a preschool-age child, a medical first.

The institute was founded by Dr. Howard House, William's brother. Today, Howard's son, Dr. John House of Pasadena, is institute president. Last year, institute doctors performed 93 implants on adults and 64 on children, some as young as 1 year old.

John House, who outfitted President Reagan with his first hearing aid (the tiny device is on display in his office), described how the 60- to 90-minute outpatient procedure can change a deaf person's life.

"A patient told me that life was like looking through a peephole in a black-and-white world," he said. "And when she got her implant, it was like the world opened up and it was in Technicolor. I thought that was kind of a cool example of what it was like."

The cochlear implant is an electronic device that stimulates the auditory nerve with electrical signals the brain can interpret as sound.

The device consists of an external processor, microphone and battery, and a surgically implanted internal receiver with electrodes embedded in the cochlea, the tiny snail-shell-shaped organ in the inner ear.

House said deafness is caused when a person loses the 15,000-plus delicate hair cells that line the inner ear. Those cells convert mechanical vibrations into electrical messages sent to the brain.

"A person who loses their hearing due to a nerve loss, loses those hair cells," he said. "They're gone. It doesn't matter how loud the sound is, there's nothing to make it go to the nerve."

The implant uses 16 to 24 multichannel electrodes to replace the missing hair cells, House said. The miniaturization of computer components and faster microchips have benefited implant wearers, he said.

The first implants were bulky, single-electrode, single-channel boxes with protruding wires. Now they're sleek, over-the-ear units, while processing speeds have zoomed from 100 hertz to 1 billion hertz.

"Which makes it so much better for the ability to process sound," House said. "We can take complex sounds and manipulate them in a multitude of ways to allow the patient to get the optimum benefit from the implant."

He stressed that implant recipients don't instantly regain normal hearing.

"It requires a great deal of work on the part of the patient and their audiologist to tune the device, or what we call program it," he said.

"When they program it, they change the program as time goes on because the patient will find that different programs work better for them. There are actually several different programs within a CI (cochlear implant), depending upon the listening situation."

House said that the earlier a deaf child receives an implant, the better. An implant allows the child to learn language skills naturally, he said, and lets him or her attend regular school classes instead of special education programs.

Kristen Corey, 25, from Vista, received her implant when she was almost 3, after spinal meningitis robbed her of hearing when she was 22 months old.

In a telephone interview, with an operator typing questions and reading Corey's typed responses, she said implants are not for everyone, but the operation helped her.

"When I got the procedure and proceeded with vocal rehabilitation, I gradually learned to accept sounds and appreciate how much better the CI helped me in understanding speech, as opposed to just speech reading without sound," she said.

Corey said she can hear 95 percent of the sounds around her, but what she hears is not the natural sound of a hearing person.

"It's like listening to a radio that's not tuned in to the correct station," she said. "There's some static and blurriness to the sound."

Casey Correia, 24, from Yorba Linda, got his implant when he was almost 6. He said, through his mother, Frankie:

"I'm extremely happy I got it. Without it, I couldn't communicate with anybody I know. I'd definitely recommend it to anybody who can get one. I don't know what life would be like without it. I love it."

Frankie Correia said her son initially struggled to use the implant and needed lots of professional support.

"He went through a lot; it was not easy at the beginning," she said. "Implants are not for everyone. You need an audiologist to work with. He needed a lot of one-on-one instruction at a language school for the deaf. He had to learn to speak and hear with the implant. It took a while for him to respond to sound and to talk clearly again."

Laurie Eisenberg, an audiologist and associate scientist in the research department of the House Institute's Children's Auditory Research and Evaluation Center, said doctors were criticized for performing the first implants on children. The procedure even ran into resistance from the deaf community, where some feared implants would destroy a well-established deaf culture.

Today, doctors are looking at auditory brain stem implants that would bypass the inner ear. So far, the procedure doesn't work as well as CIs, Eisenberg said. Scientists have speculated that electrodes may not be planted in the right place on the brain stem, she said.

House envisions a day when CIs will be totally implanted: "When we can implant them so that there's no external components. That's obviously sometime in the future," he said.

Both House and Eisenberg mentioned institute experiments with hair cell regeneration.

"If we can get them to regrow, then we won't have to worry about CIs," he said. "We're able to show some results in animals. Certain animals do it naturally, like fish and birds.

"Most mammals don't, but we've been able to do it in mice, which are not too far from humans (in the structure of their inner ears). There's been some progress, but that's a long way away."

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