Medical Breakthrough: Hear Clearly

Wednesday, December 22nd 1999, 12:00 am
By: News On 6

Background:28 million Americans suffer from hearing loss, yet many do not get the help they need. The condition is not only frustrating, but dangerous as well. Many people that have hearing loss are not even aware they have a problem. Wax blockages, infection or some other easily treatable problem can cause hearing loss. It can also be caused by overexposure to loud noises or simply genetics. Damage to the hair cells and cochlea (inner ear) caused by genetics or overexposure to sound is the largest single form of hearing loss affecting 17 million Americans. Excessive sound exposure damages hearing by over stimulating the tiny hair cells within the inner ear. There are between 15,000 and 20,000 of these microscopic sensory receptors in the cochlea. When these hair cells are damaged, they no longer transmit sounds to the brain.

Hearing Aids:Hearing aids can help people who suffer from hearing loss which can not be fixed by surgery or medicine. Traditional hearing aids are made up of a microphone which captures the sound, an amplifier which makes it louder and a speaker that turns it into a louder sound and sends it to the inner ear. One problem with this type of aid is that because all three parts are so close together, there is often acoustic feedback or a squeal. The problem is somewhat corrected by sealing all the sound into a tight-fitting ear-mold, but that often causes distortion. Essentially, very loud sounds are being sent into a very small space. Also, the device can be uncomfortable to wear. For these reasons, many people who do have hearing aids do not wear them.

Using Magnets:Jonathan Spindel, Ph.D., a biomedical engineer at the University of Virginia, is studying a hearing aid that uses magnets to transmit sound. The goal with the new device is to get vibrational energy into the inner ear by means other than sound.
Instead, increased energy is sent into the ear to make sound.

First, a mini-microphone is implanted in the ear that captures the sound. From there it is sent through a small processing unit and an electromagnetic coil, both of which are also implanted. These amplify the vibrations which are sent to the inner ear. There, a magnet the size of a pencil-point takes the vibration and sends it into the cochlea where the tiny hairs are stimulated and noise is produced.

Other New Ways:There are also a number of newer hearing aids on the market that can help with hearing loss. They are digital and can be custom-programmed to amplify only the frequencies that cause the most trouble.

For more information, contact:

Marguerite Beck
Director, Media Relations
University of Virginia
Box 800795
3078 McKim Hall
Charlottesville, VA 22908
(804) 924-5679