BOSTON -- A team of US researchers found that soldiers exposed to even one bomb blast can develop chronic traumatic encephalopathy (CTE), a degenerative brain disease usually found in boxers, football players and hockey players who experience repeated head trauma.
Researchers from Boston University studied the brains of four deceased US military personnel who were exposed to a blast alongside the brains of four deceased young athletes who had a history of repeated concussions.
The signs of CTE in the brains of the blast-exposed veterans were "virtually indistinguishable" from the marks of the disease found in the brains of the young athletes, said co-leader of the study Ann McKee.
The early stages of CTE, which can only be diagnosed postmortem, are characterized by abnormal brain deposits of a protein called tau. A similar build-up occurs in Alzheimer's patients and these tau lesions eventually lead to brain cell death.
CTE is suspected of have connections to symptoms such as depression, memory loss, erratic behavior and dementia.
The researchers believe it is not the shock wave, but the blast wind from an improvised explosive device, or IED, that leads to traumatic brain injury (TBI) and later CTE in soldiers.
An IED's blast wind can reach speeds up to 330mph (531kph) -- faster than any wind gust ever recorded on earth.
"Our study provides compelling evidence that blast TBI and CTE are structural brain disorders that can emerge as a result of brain injury on the battlefield or playing field," said co-author Lee Goldstein.
"Now that we have identified the mechanism responsible for CTE, we can work on developing ways to prevent it so that we can protect athletes and our military service personnel."
TBI may affect about 20 percent of the 2.3 million servicemen and women deployed since 2001, the researchers said.
Their findings were published Wednesday in Science Translational Medicine.