“Earning potential drops if you can’t communicate,” said Lt. Col. Mark Packer, MD, a neurotologist and director of the Department of Defense’s Hearing Center of Excellence. “So if you have a $30,000 drop in pay, that’s also $30,000 that’s not getting taxed. Hearing loss affects much more than just the individual and the individual’s family.”
Explore This IssueJanuary 2013
Military physicians and safety officers are working in concert with civilian physicians, researchers and scientists to better protect troops’ hearing, and to restore hearing and quality of life post-service.
The Problem: Constant and Acute Noise Exposure
Military members experience unique auditory environments. While it’s not uncommon for civilians to work in chronically noisy environments, the duration and intensity of exposure is typically increased in military environments. “In the civilian sector, you have people working eight- to 10-hour days in fabrication, manufacturing and construction. Noise levels can be as high as 118 dBA,” Yankaskas said. “When you go to a military operation, the decibel level can be much higher, and it can be for 24 hours a day.”
Service members who work on ships or around airfields are chronically exposed to high levels of noise. But military members are also at risk for acute auditory insults. Active military operations in both Iraq and Afghanistan have increased the number of service members exposed to bombs, weapons fire and blasts, changing both the nature and mechanism of the auditory injury.
“Chronic noise exposure affects hearing within the sensory organ and cochlea; the hair cells are toxified by chronic exposure to loud noise,” Dr. Packer said. “Blast injuries can be much more traumatic. The peak pressures in the ear rise much more quickly, so the impact on the hearing system is not chronic and insidious but explosive. Some of the injuries we see from blasts not only show sensory hearing loss but also brain injury, tympanic perforation and disruption of the ossicular chain. The blast may also create flying debris, so there are secondary blunt impacts and trauma. And if you’re close enough, severe heat injuries and burns can also happen at the same time.”
Often, hearing is a secondary consideration; when a solider is injured, preference is always given to life-threatening injuries, and hearing injuries are often invisible. Some resolve quickly, for reasons physicians don’t quite understand. “Some patients who come in with complaints of hearing loss and tinnitus following an acoustic or blast-related injury will have subjective improvement fairly rapidly, but most patients do not. In the theater, audiometric testing is usually not available,” said Lt. Col. Mitchell Ramsey, MD, an otolaryngologist who served in Afghanistan. “Many factors contribute to presence or absence of recovery, including the blast intensity, innate inner ear tolerance to injury, co-existing conditions, prior trauma and probably many others, all of which need to be further researched.”