London, Oct 14: 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.

Bureau Report