Hearing Loss From Explosions May Be Treatable, Mouse Study Hints
Researchers say findings might help people after airbag injuries, bomb blasts
MONDAY, July 1, 2013 (HealthDay News) -- Long-term hearing loss caused by explosions and other extremely loud noises may be treatable, according to a new study of mice.
The findings could be good news for soldiers deafened by roadside bombs and gunfire or civilians who've lost their hearing from sources such as jet engines or deploying air bags.
In their experiments with mice, Stanford University School of Medicine researchers found that loud blasts cause hair-cell and nerve-cell damage -- rather than structural damage -- to the cochlea, which is the auditory portion of the inner ear.
"It means we could potentially try to reduce this damage," study senior author Dr. John Oghalai, an associate professor of otolaryngology, said in a Stanford news release.
Previous studies have concluded that explosions shred and rip apart the cochlea, which is extremely delicate. If that was the case, the damage would be irreversible, according to the news release. The findings in those studies may be due to the use of older, less sophisticated imaging techniques, the researchers said.
The Stanford team exposed mice to loud blasts and then used a micro-CT scanner to examine the inner workings of the rodents' ears, in the study published July 1 in the journal PLoS One.
"When we looked inside the cochlea, we saw the hair-cell loss and auditory-nerve-cell loss," Oghalai said. "With one loud blast, you lose a huge number of these cells. What's nice is that the hair cells and nerve cells are not immediately gone. The theory now is that if the ear could be treated with certain medications right after the blast, that might limit the damage."
Much of the hearing loss caused by explosions and other extremely loud noises is caused by the body's immune response to the injured cells.
"There is going to be a window where we could stop whatever the body's inflammatory response would be right after the blast," Oghalai said. "We might be able to stop the damage. This will determine future research."
While the findings of the new study are promising, scientists note that research involving animals often fails to produce similar results in humans.
The U.S. National Institute on Deafness and Other Communication Disorders has more about noise-induced hearing loss (http://www.nidcd.nih.gov/health/hearing/Pages/noise.aspx ).
SOURCE: Stanford University, news release, July 1, 2013