Friday, April 10, 2009

Military studies shed light on brain injuries

Military studies shed light on brain injuries

By Gregg Zoroya - USA Today
Posted : Wednesday Apr 8, 2009 16:33:32 EDT

ARLINGTON, Va. — Military scientists are learning how roadside bombs — the most common weapon used against U.S. troops in on the battlefield — harm the brain even when there is no other physical damage, according to research results released by the project’s lead scientist.

Researchers discovered a sliding scale of injury ranging from brain cell inflammation to cell damage or cell death, depending on the power of the blast, said Army Col. Geoffrey Ling, a neurologist at the Defense Advanced Research Projects Agency.

Future research that builds on these findings may lead to ways battlefield medics can use a combination of helmet sensors and over-the-counter pain reliever to identify and treat mild cases of blast-caused brain injury, Ling said.

Scientists also found that brain damage from an improvised explosive device can be made worse for those riding inside an armored Humvee because materials in the vehicle magnify the blast wave effect, Ling said.

Up to 360,000 veterans of the wars in Iraq and Afghanistan may have suffered brain injuries, the Pentagon announced in March. Many of those injuries are from IED blasts, and about 90 percent are so-called mild cases, in which recovery is expected.

An estimated 45,000 to 90,000 victims, however, suffer persistent symptoms such as memory loss, lack of balance and problem-solving difficulties.

“This really sheds light where there was none,” said Army Col. Mike Jaffee, director of the Defense and Veterans Brain Injury Center. “I think it’s extraordinarily important. It’s some of the first research and findings that help to illustrate ... the evolution of” traumatic brain injury.

During an 11-month period of research ending in December, scientists wrapped pigs in body armor and placed them in a Humvee simulator, in open fields and in a closed room and subjected them to varying degrees of explosions at a research laboratory in a location researchers declined to disclose. Pigs were used because their brains are structured much like the human brain, Ling said. Rats also were part of the study that has cost about $10 million so far.

Some key preliminary findings from the studies:

• A blast can injure the brain even without shrapnel or a victim being knocked down. The power of the explosion in the first fraction of a second — known as the primary blast effect — can damage or destroy brain cells in ways conventional imaging devices cannot see.

• The brain can tolerate low levels of blast, measured in pounds per square inch. At a certain pressure level that Ling would not disclose, brain cells become inflamed. At higher levels, cell death begins, Ling said.

• Brain cell inflammation occurs in mild TBI cases, he said. It caused balance and coordination problems in pigs, but healed in hours or weeks depending on the blast severity, Ling said. “It’s probably what a lot of the guys [in combat] are getting,” Ling said. “Shaken up a little bit, but they recover quickly. No surprise. That’s the natural order of the disease.”

• In the most severe of these mild cases, the inflammation can damage areas of the brain that have been associated with the later onset of Alzheimer’s and Parkinson’s, Ling said. No connection between the blasts and these later diseases has been proved, he cautioned.

• Research will continue to determine whether basic over-the-counter drugs such as Motrin can help reduce the inflammation, Ling said, which could help treat troops suffering mild TBI on the battlefield. “That would be awesome,” he said.

• As scientists learn more about how much of a blast can cause brain cell inflammation or worse, they may use helmet sensors to alert medics when a service member needs a break from combat to heal a mild brain injury, Ling said. That would help scientists diagnose or identify the soldiers who are most at risk, he said.

• Unlike a blow to the head, where damage occurs at the point of impact, blast damage radiates across the brain, although it’s heaviest on the side facing the explosion, Ling said.

Pentagon: Pigs used for brain-injury testing

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