Designed to be attached to the cochlea, the implant comprises tiny, flexible bar-shaped elements which are coated with a special film that makes them vibrate in response to sound, it says.

Advertisement

Responds to wider range
By adjusting the length and diameter of each element, the researchers can tune each bar to resonate in response to a different, narrow range of frequencies.

When the bar vibrates, the flexing of its piezoelectric coating produces a tiny voltage which is transmitted directly to the auditory nerve in the cochlea, which then sends on the signal to the brain.

Existing inner-ear implants have a very limited range of frequencies that enable deaf people to pick up speech. But they are not very good for picking up the broader frequency ranges in music.

Conventional hearing aids, meanwhile, only amplify sound rather than make it clearer.

Commercial version
The prototype cochlear implant devised by Britain's National Physical Laboratory and Institute of Nanotechnology has four vibrating bars.

The scientists intend to boost this to 10 bars to pick up speech and believe 20 or maybe more will be needed for listening to music.

A commercial version of this early work is likely to be at least a decade away, being the time needed to miniaturise the two-square-centimetre device so that it fits into the inner ear.

Users will have manual control
Once it is complete, users will have manual control over what they want to hear, New Scientist says.

For instance, they could tune in to individuals in a crowded room and filter out the background chatter.

Unlike existing implants, the device would not need an external supply, as the piezo coating by itself produces the necessary voltage. – (Sapa-AFP)

Visit our Hearing Centre for more information.

October 2005
 

Print this article on

Rate this article Poor 1 2 3 4 5 Excellent