ROSSLYN, Va., Sept. 11, 1998 --Imagine an invisible hearing aid that never squeals with feedback and digitally enhances speech while silencing background noise.
Such a device is under development and has been tested in animals with encouraging results. Jonathan Spindel, Ph.D., a biomedical engineer and assistant professor at the University of Virginia's Department of Otolaryngology, is preparing to take the next step toward developing a fully implanted prototype for humans.
"Our tests to date have shown that the signals produced with our magnetic hearing device are very nearly those of natural acoustic sound," said Spindel.
The unique device would capture sounds with a miniature microphone implanted in the ear. After passing through a small processing unit and an electromagnetic coil, both also implanted, amplified vibrations would be sent to the inner ear via a tiny magnet attached to the inner ear's round window, a thin membrane at one end of the cochlea.
About as large as a pencil point, the tiny magnet would send vibrations through the cochlea, the fluid-filled organ shaped like a snail shell, and stimulate its thousands of hair cells used in normal hearing. The new device is the first to use an electromagnet to stimulate the inner ear via the round window.
A major feature of Spindel's approach is that the device doesn't obstruct the normal hearing process. "Leaving the middle ear system intact and establishing a second independent input pathway to the inner ear opens the possibility for using the normal acoustic pathway and round window electromagnet simultaneously to establish constructive and destructive sound patterns in the inner ear," said Spindel.
The device could enhance the sound of a person's voice, for example, by
generating sound waves matching those of the voice as it reaches the ear.
What ultimately reaches the brain and what the user actually h
Contact: Mark Bowman