UF researchers find way to test hearing-loss drugs in humans
Published: Tuesday, February 12, 2013 at 11:22 a.m.
Last Modified: Tuesday, February 12, 2013 at 11:22 a.m.
For troops in the line of fire, hearing loss is most likely a secondary issue, but in the past decade, those returning from Iraq and Afghanistan are showing signs of permanent hearing damage, and a recent University of Florida study might pave the way for treatments to reduce and prevent at least some of that damage.
Colleen Le Prell, an associate professor in the department of speech, language and hearing sciences at the UF College of Public Health and Health Professions, led a study in which researchers created temporary, reversible hearing loss in 33 college students in order to test how well anti-hearing loss drugs work.
"Right now the only options for protecting against noise-induced hearing loss are to turn down what you're listening to, walk away from it or wear ear plugs, and those options may not be practical for everyone, particularly for those in the military who need to be able to hear threats," Le Prell said in a UF news release.
Le Prell, in an interview, added that hearing loss and tinnitus (ringing in the ears) are the top two disabilities for returning troops, with treatment costs exceeding $1 billion.
The Army wouldn't comment on a specific dollar amount, but Lyn Kukral, the public affairs officer for the U.S. Army Public Health Command, said: "The cost to the Army associated with auditory injuries can be high."
Kukral added that hearing loss creates many costs — from operational costs caused by failed missions to the costs involved in retraining a soldier with hearing loss in a role with fewer hearing demands, in addition to treatment costs.
In combat situations specifically, "reduced hearing of environmental sounds, decreased speech understanding and ‘phantom' auditory sensations" are some of the hearing-related problems that compromise a soldier's ability to respond to dangerous situations, Kukral said.
Le Prell's study, published in the November/December issue of the journal Ear & Hearing, recruited 33 healthy UF student volunteers to listen to rock and pop music for four hours on headphones from a decibel range of 93 to 102 (a lawnmower to a loud truck). Their hearing then was tested every 15 minutes for three hours after they had listened to the music, then the next day and one week later.
Only the students who had listened to music levels at the highest levels suffered some hearing loss, but their hearing was back to normal within three hours after they had stopped listening.
This model — the first to cause low-level, temporary hearing loss with music — can now safely be used to test anti-hearing loss drugs in humans, Le Prell said.
That opens a huge door, since until now, drugs have been tested only in animals — and those studies suggest that the same drugs can be used to treat temporary and permanent hearing loss, Le Prell said.
Antioxidant drugs are especially promising in preventing hearing loss.
"We are trying to protect the (outer hair) cells so they are not damaged in the first place," Le Prell said.
"Almost every case, regardless of which specific antioxidants … there has been a reduction in noise-induced hearing loss in animals."
Hearing loss prevention drugs could help troops, factory workers and other professionals working in noisy environments, Le Prell said.
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