STORY BYPart II of Now Hear This!
Until Bethany Boyles was 15, her hearing was like a symphony. Her ears composed the spectrum of sound, and she could hear all the distinct, rich and subtle noises around her. A car accident in 1980 damaged her middle ear, deafening her right ear. Over the next four years, as a result of her injuries, the hearing in her left ear also began to diminish.
By the time Boyles was in her late 30s, she couldn’t use the telephone or hear the radio over the road noise in her truck.
A cochlear implant in 2003 helped restore hearing in her right ear. Then, late last year, Boyles became one of a growing number of hearing-impaired patients to get a second cochlear implant in the other ear. The bilateral implant, she says, was literally music to her ears.
In the past, because Boyles had some amount of hearing, she wouldn’t have been a candidate for one cochlear implant – much less two. But as a result of technological improvements related to the devices, cochlear implants are becoming an option for more patients with significant levels of residual hearing function.
Dr. C. Y. Joseph Chang, professor and chairman of the Department of Otolaryngology – Head and Neck Surgery at The University of Texas Medical School at Houston, says people who don’t benefit from traditional hearing aids may be candidates for a cochlear implant, a medical device that can functionally restore hearing.
Unlike a hearing aid that amplifies sound, the implant bypasses the damaged part of the ear and sends sound signals directly to the auditory nerve. It is surgically placed under the skin behind the ear and has an external device that looks like a hearing aid which includes a microphone, speech processor, transmitter and receiver/stimulator and electrodes.
“The technology has changed since cochlear implants were developed in the 1970s,” Chang says. “Instead of a single electrode, it is now a multi-channel device, which gives improved performance. Also, the hearing loss criteria have changed. Initially, cochlear implants were only for people who were stone deaf and had no hearing at all. The criterion is now based on the number of words a patient understands during a test, so more will qualify for a cochlear implant.”
A small but increasing number of those patients may benefit from a second cochlear implant, Chang says.
“Bilateral cochlear implants have only been offered commercially in the last year,” he says. “Most benefit from the first implant. They can hear, but they can’t hear where the sound is coming from. With a second implant, they are better able to figure out where the sound is coming from and also hear better in noisy environments.”
Boyles, a patient of Chang’s, says her hearing vastly improved with the first implant. She no longer had to rely solely on her lip-reading skills. She could listen to talk radio in her truck on the way to work. She actually took up violin lessons, but even with “a very patient” teacher, playing was a struggle.
The second implant helped her hear in stereo. “It’s nothing short of a miracle,” says Boyles, an active volunteer with the Hearing Loss Association. “I am now beginning to hear the fine differences between the notes when I play the violin. And when I listen to a song on the radio, I can tell what instruments are being played.”
Chang says these are exciting results for adults like Boyles who once could hear normally and for children who were born profoundly deaf and never knew sound until they received a cochlear implant.
“The newer devices are producing more natural sound,” Chang says. “And in the future, I think they will continue to improve the sound processing and electrodes.”
He expects that cochlear implants will one day be completely implantable, eliminating the need for an external ear piece. “It’s only going to improve and give patients the ability to hear and hear better,” Chang says.
He cautions that even with the technological advances, the cochlear implant is not for everyone with profound hearing loss. Those who benefit from hearing aids are not candidates.
“Once you implant the cochlear device, because you drill into the middle ear, the natural hearing is gone,” Chang says. “That means once you have a cochlear implant, you can’t go back to hearing aids.”
As with any surgery, there are risks. Patients could suffer an injury to the facial nerve during surgery, dizziness, ringing in the ears, cerebrospinal fluid leakage or an infection at the site of the incision.
Patients with cochlear implants also appear to be at an increased risk of developing meningitis, an infection of the lining of the surface of the brain. Because of that, the U.S. Food and Drug Administration recommends that patients be vaccinated against meningitis before undergoing surgery.
Boyles says patients should not expect to hear as soon as they wake up from surgery. Physicians wait about a month for everything to heal before they activate the sound processor. Even then, hearing is a work in progress, she says.
Patients may need auditory verbal therapy and they also need to visit their audiologist routinely to have the processor checked for adjustments and upgrades. “Like everything else that is worth it, it takes time and work,” Boyles says. “Practice listening, and don’t get frustrated. It does get easier, and trust me, it’s worth it.”
Last Updated: 02-03-2006
Dr. Joseph Chang is professor and chairman of the Department of Otolaryngology—Head and Neck Surgery at the UT Medical School.
See Dr. Chang also at:
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