Science / Medicine : Studies of Birds’ Ears Offer Hope to the Deaf

Two studies of key cells in the inner ear of birds may suggest a possibility of developing therapy to correct deafness caused by exposure to loud noises.

In companion studies published in the journal Science, researchers report that after exposure to traumatic levels of noise, adult quails and young chickens are able to regrow damaged cells essential to hearing. The studies suggest that there is a hormone or protein secreted by the damaged cells that causes a growth of the replacement cells.

Edward W. Rubel of the University of Washington, part of the quail study, said, “We have not found a cure for deafness, but we have found something in the ear of birds that we haven’t before thought possible.”

“We can’t yet show that it happens in mammals or humans,” but the discovery offers a possibility of correcting one type of deafness in humans, said Douglas A. Cotanche of Boston University, part of the chicken study.

Both studies concentrated on an inner ear organ called the cochlea. The researchers discovered that when sensory cells within the cochlea are destroyed by loud noise, some chemical process causes the growth of new cells, apparently restoring a key link in the hearing process.