Some soldiers walk away from explosions with no obvious injuries, but the concussion can have a lingering effect.
"A lot of time, there are no outward signs,” Schlegel said. "There's no bleeding and the only indication is if the soldier or his buddies say this guy is just not acting right. A lot of these injuries are similar to a football concussion.”
Most brain injuries are mild, and soldiers can recover with rest and time away from the battlefield. But the military estimates that one-fifth of the troops with these mild injuries will have prolonged or lifelong symptoms requiring continuing care.
Thirty percent of soldiers taken to Walter Reed Army Medical Center since 2003 suffered traumatic brain injuries, according to the Defense and Veterans Brain Injury Center.
The brain injury center, which has seven facilities around the country, has seen 2,669 patients between 2003 and 2007. But doctors believe many less obvious brain injury cases go undetected.
Funds for the testing project come from the Office of the Surgeon General of the Army and a $1.6 million grant from the U.S. Department of Defense.
Contributing: The Associated Press