Scientists find key protein helps people hear

LONDON (Reuters) - A protein in the inner ear helps

people differentiate between sounds and understand

speech, French researchers reported on Wednesday in a

finding that could help treat the hard of hearing.

The study also helps explain why some people have

difficulty hearing in crowded restaurants or other noisy

places, said Paul Avan, a researcher at the University of

Auvergne in Clermont-Ferrand, France.

"This won't help cure deafness but will help diagnose why

some people have hearing problems, especially in noisy

places," Avan, who worked on the study, said in a

telephone interview.

The study, which used genetically engineered mice,

looked at the part of the inner ear called the cochlea,

which contains two types of sensory cells to detect

sounds.

Scientists often study mice because of the biological

similarities between the animals and humans.

Until now people had thought that structures called ion

channels found in the cells -- which work like a

microphone to transform sound into electrical messages

to the brain -- were mainly responsible for distorting sound

in the inner ear.

Distortion is important because it allows people to pick out

the correct sounds from a mixture of noises whether it be

competing conversations at a cocktail party or other kinds

of background noise, Avan said.

But the researchers showed how a protein called

stereocilin -- not the ion channels -- was keeping sensory

cells intact and allowing the inner ear to properly distort

sounds, Avan said.

Mice without stereocilin did not hear properly even when

their ion channels worked, Avan and colleagues reported

in the journal Nature.

The findings could help doctors diagnose more subtle

hearing problems and fit certain people with special

hearing aids that eliminate noise coming from certain

directions, Avan said.

"Until now it was thought that if the ion channels worked

everything would be okay," Avan said. "We show that this

is not the case. Sensitivity will be good but that does

nothing if you don't understand anything if it is noisy

around you."

(Reporting by Michael Kahn; Editing by Maggie Fox and Opheera McDoom)

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