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Life has grown quieter recently in the North Side home of Conrad Hart.
Since doctors turned on his newly implanted hearing aid last month, "I don't have to have the radio and everything else turned up as high it will go," explained Hart, 66.
There's less noise, but he hears more.
Hart was one of four patients to have the still-experimental hearing aid implanted in his ear in March at Allegheny General Hospital.
Conventional hearing aids amplify sounds before they reach the eardrum. Implantable hearing aids, by contrast, directly stimulate the bones of the middle ear. The Envoy model made by St. Croix Medical Inc. that is being tested at Allegheny General thus far is the only fully implantable version; it uses the eardrum as its microphone, rather than relying on an external microphone.
For patients such as Hart, whose hearing loss was so great that conventional aids were losing their ability to help, the implantable aids promise to restore hearing. But eventually, if the devices prove reliable, they may offer an alternative to millions of people who have milder hearing loss, but hate the idea of having a visible hearing aid, said Dr. Moises Arriaga, co-director of the hospital's Hearing and Balance Center.
For now, the experimental device is not for everyone, emphasized Dr. Douglas Chen, the other co-director. "This technology is really pushing the envelope," so investigators will be monitoring its longevity, looking for signs of rejection by the body and checking for any coupling problems that develop between the hearing aid and the ear.
The implantable device is powered by the same type of battery used in cardiac pacemakers and should last between three and five years. Minor surgery will be required to replace the battery. Arriaga said the device's sound-processing circuitry also is replaced along with the battery, so users can enjoy the advantages of the latest electronic advancements.
Of the first four patients, two have had to undergo second surgeries because the device's stimulator was not properly engaged with the stapes bone of the middle ear, Arriaga said. Both of those patients are still healing and their aids will be turned on in about a month.
But both Hart and Donna Burk, 58, of Greensburg, report good results since their hearing aids were activated last month.
Ten patients will be implanted during this first phase of the clinical trial, five at Allegheny General and five at Virginia Mason Medical Center in Seattle. A second phase, if approved, might include another 50 patients.
All of the initial patients had the hearing aid implanted in only one ear, in case problems arose. So Hart has the Envoy in his left ear and a conventional hearing aid in his right.
"There's a lot of difference between the left and the right," he said, noting his left ear is no longer bothered by background noise and feedback. That's been a boon to him in his role as secretary for the East McKeesport Masonic Lodge. "It was getting hard to hear the guys talk from the floor."
A truck and auto mechanic for 40 years, he attributes his hearing loss to a noisy work environment. But he also admits that he ignored his steadily deteriorating hearing for almost two decades. Five years ago, his wife and family got so fed up with his "Huh? Huh?" replies to them that he finally got his hearing checked. He was soon fitted with a pair of hearing aids.
The implantable aid requires some fine tuning once it has been activated and Hart's device is not yet set at its full volume. Still, the sound is clear enough that Hart finds he can sometimes turn off the conventional hearing aid in his right ear.
"It's working beautiful."
Friday, June 21, 2002
By Byron Spice, Science Editor, Post-Gazette
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