The scourge of deafness has always tortured humanity, from everyday senior citizens to classical composer Beethoven. However, new research may see a sea change in the battle against hearing loss.
Intercollegiate research led by Gary Housley of the University of New South Wales has given science a brand new direction to go in when studying noise-induced hearing loss. This is big news for anyone who attends concerts or works in construction and other loud environments.
Scientists have discovered, in lab mice, genetic mutations which control the receptor for the hormone ATP inside the inner ear’s cochlea. The cochlea is a snail-shaped organ which uses tiny sensory hairs to detect vibrations and send those auditory signals to the brain. If the receptors are turned off from a certain mutation, then the mice experienced no temporary hearing loss after exposure to loud noises but they are more susceptible to permanent, long-term hearing damage.
This is the first evidence of a new mechanism which protects us from loud noises. In humans, this defense registers as an “underwater” or “fuzzy” character to sounds heard after attending loud places like concerts or nightclubs.
Ann Hickox, a post doctorate research associate with the speech and hearing department, works daily in the auditory physiology lab. Hickox finds this new research exciting, but still doesn’t expect any direct medical applications for a long while.
She also wants to make sure students understand just because temporary hearing loss goes away a day or two after a concert doesn’t mean your ears are healthy again. She is aware of not-yet-publicized research which shows there is often still subtle and cumulative permanent hearing loss after an apparent recovery.
“Our field thinks of two kinds of hearing loss after loud exposures – we think of temporary and of permanent hearing loss,” Hickox said. “It’s too simplistic to think they’re a continuum, too simplistic to think that if you just keep upping the exposure you get from temporary to permanent. They’re actually different processes going on.”
While Housley’s team’s research may lead to future drugs to help prevent hearing loss in people like musicians or factory workers, Hickox still referred to it as “pie in the sky” at this stage.
This research on temporary hearing loss came just one month after another study done this year which shows promise as a path to restoring permanently lost hearing. Current knowledge says once sensory hair cells die, that range in one’s hearing is lost for ever.
Albert Edge and his team at Harvard Medical School have been working with an experimental drug named LY411575. It shows promise in preventing a protein named Notch from keeping stem cells dormant. This allows these cells to develop into new sensory hair cells. Because the stem cells are the patients’ own, there should be no negative ethical and political judgements to interfere with research.
Don’t hedge your lifelong hearing bets on this research alone. Instead, Hickox has a simple solution to permanent damage and tinnitus, the ringing in the ear after loud exposures – invest in a pair of $30 musician’s ear plugs.
“A lot of people that enjoy concerts don’t want to wear ear plugs because they’re afraid it will lessen their experience,” Hickox said, “that it’s going to make the sound distorted. But there’s been a lot of advancements ... It will attenuate the sound without distorting so much ... Some who wear them say they enjoy the music more because it sounds less distorted and is a less painful volume.”
In spite of this advice, students more often than not go into loud situations with no protection. Julia Lewter, a sophomore in the College of Liberal Arts, worries after concerts which give her tinnitus but hasn’t taken precautions. It seems for some to be a problem of culture.
“I know a friend who has a pair (of quality ear plugs),” Lewter said, “but she never wears them because she thinks she’ll look goofy or like she isn’t enjoying the show as much as those around her.”