Brain Implant for Deafness

February 10, 2010 12:00:00 AM PST
Living in a world of complete silence can be difficult, and for certain types of deafness, even cochlear implants don't help. Surgeons are turning to a new type of implant that helps retrain the brain and open up a new world of sound.Danny Sanborn wishes he could go back to a time before his world went silent. He suffers from a disease that causes brain tumors. In order to get the tumors out, doctors had to sacrifice his auditory nerve.

"Before I had the tumors, I had hearing, but as soon as they took the tumors out, I didn't have any," Sanborn told Ivanhoe.

A cochlear implant wasn't an option, so surgeons put in an auditory brainstem implant or ABI to restore certain sounds.

"We are bypassing the auditory nerve to directly stimulate the next level of sound processing in the brain," Daniel Lee, M.D., a surgeon at Massachusetts Eye and Ear Infirmary in Boston, told Ivanhoe.

Surgeons place 21 electrodes on the bundle of nerves that sit on the brain stem, the lower part of the brain.

"The electrodes provide electrical current," Dr. Lee explained. "It stimulates those nerves that are responsible for continuing a signal of sound to the rest of the brain."

A tiny microphone is positioned by the ear. It picks up sounds from the environment and digitally transmits them to a decoding chip placed under the skin. The chip stimulates the electrodes, allowing the patient to hear sounds.

It doesn't restore complete hearing, but Sanborn is now able to hear the phone, an alarm clock and even his best friend.

While the device can restore some hearing, it can't restore a patient's balance that is damaged by the tumors. Up to one in 25,000 Americans suffer from the condition that causes hearing loss like Sanborn's, called NF2.

If You Would Like More Information, Please Visit:
Public Affairs
Massachusetts Eye and Ear Infirmary
(617) 573-4170
http://harvardabi.org


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