Study links some ear damage to brain injuries
Mideast edition, Sunday, August 26, 2007
WASHINGTON — Eardrum damage resulting from the blast waves of explosions could be a sign of undetected traumatic brain injury among troops, according to new research unveiled last week.
One of the authors of the study, which tracked 662 blast injury survivors, said the data should serve as a warning to physicians and troops to watch for long-term neurological damage even after what seems to be a minor ear injury.
“A lot of troops, they get knocked unconscious or lose some hearing after an explosion, but they laugh about it,” said Air Force Dr. (Lt. Col.) Michael Xydakis, an assistant professor at the Uniformed Services University of the Health Sciences. “They just don’t see it as a potentially serious injury. But it can be.”
The research, done while Xydakis and his colleagues were stationed at Iraq’s Balad Air Base in late 2005, shows a troop whose eardrums were damaged by the blast waves of roadside bomb explosions were significantly more likely to also be knocked unconscious in those attacks.
A blow that renders servicemembers unconscious could cause brain trauma even if they come to quickly, and show no immediate signs of trouble.
Nearly 61 percent of patients who had perforation or tears in their eardrums blacked out in the blasts. Only about 22 percent of those whose eardrums were unharmed were hit hard enough to lose consciousness.
Xydakis said the relationship isn’t a major surprise; Other studies his team has worked on shows similar connections between retinal bleeding and loss of smell after explosions and subsequent blackouts.
But the force needed to damage these more obvious functions is also enough to cause potentially long-term cognitive problems, especially if patients aren’t given time to recover, he said.
“The idea is always triage, to deal with patients right away and then to quickly return them to their unit,” Xydakis said. “But this may be a sign there is more damage, and that they need more time.
“For troops who know their hearing is down or their (eardrum) was perforated, they should have a higher index of suspicion about how healthy they are.”
Researchers could not pinpoint exactly how much of a blast wave was needed to knock troops unconscious, but Xydakis warned that the equivalent of twice atmospheric pressure is enough to cause damage to the inner ear — a measurement easy to achieve in a sizeable explosion.
The research was published in the Aug. 23 issue of the New England Journal of Medicine.
Symptoms of ruptured eardrum
n Hearing loss, either partial or total
n Ear noise/buzzing
n Earache or ear discomfort
n Bleeding or drainage from the ear
Source: National Institutes of Health