Soldiers at War Can Escape Blast Shrapnel, Yet Suffer Brain Injuries

2 conditions diagnosed; symptoms often overlap 
by Carol Smith

The overlap between classic symptoms of post-traumatic stress disorder and those of mild traumatic brain injury is substantial. Even those who appear to have no external damage from explosions can suffer lasting brain injury that causes behavioral and other symptoms.

To make a definitive diagnosis, doctors use both brain scans and neuropsychological testing. Often the two conditions coexist.

Anger outbursts, in particular, can be a sign of concussion, or PTSD, said Dr. Evan Kanter, a psychiatrist who works at the University of Washington and the VA Puget Sound.

The amygdala, an almond-shaped mass of neurons buried in the temporal lobe of the brain, is sometimes called the "emotional" or dinosaur brain, and thought to be one of the critical areas that govern strong survival instincts…

"It’s responsible for powerful emotions — anger and fear," Kanter said. This is where the "fight or flight" instinct comes from.

"In PTSD, the amygdala is hyperactive," said Kanter, who works with vets who have PTSD.

The other part of the brain involved in modulating emotions is the frontal lobe. It allows for our executive functions — planning, guidance, thought, deciding you’re going to do something, or not.

With PTSD, it’s like the frontal lobe goes off line and the amygdala is in control, Kanter said.

With traumatic brain injury, the actual nerve connections in the frontal lobe and amygdala seem to be disconnected.

"Practically, what you see in both cases is terrible anger problems," he said.

The mechanism of damage is complex and largely unknown, but appears to be related to the nature of explosions.

The leading edge of a bomb explosion in Iraq, the "blast wall," travels at supersonic speeds, generating a blast wind, then a massive sucking vacuum in its wake. Helmets can protect the brain from flying fragments and debris, but not the rapid compression and decompression of shock waves. The pressure fronts slam through the brain’s 3 pounds of fragile white and gray matter, shearing delicate neural connections, disrupting cellular function, and, some believe, littering the brain with microscopic cavities like ghost shrapnel.

No one knows yet what cumulative exposure to multiple blasts might do to the brain.

So far, polytrauma centers that see veterans with multiple injuries from the war are diagnosing at least 20 percent with some kind of brain injury, said Jay Uomoto, neuropsychologist and director of the Center for Polytrauma at the VA Puget Sound. And that number is likely to grow.

PTSD AND VETERANS

Treatment can shorten the duration of symptoms. About 40 percent of people with PTSD recover within the first year. However, one-third to one-half of people with symptoms do not fully recover even after many years.

PREVALENCE OF PTSD

Vietnam veterans: 9 percent to 15 percent

Gulf War veterans: 2 percent to 10 percent

Afghanistan active duty: 6.2 percent

Iraq active duty: 12.6 percent

U.S. general population: males — 5 percent; females –10.4 percent

Source: VA Puget Sound

WHAT TO LOOK FOR

Some symptoms of TBI: headaches, dizziness, memory problems, ringing in ears, irritability, sleep disturbances, trouble concentrating, slowed thinking, fatigue, sensitivity to light or noise, anger problems.

Some symptoms of PTSD: memory problems, loss of appetite, trouble concentrating, slowed thinking, fatigue, re-experiencing trauma, disturbed sleep, startle reflex, anger outbursts.

ON THE WEB

For more information on traumatic brain injury: Defense and Veterans Brain Injury Center, dvbic.org.

For more information on PTSD: ncptsd.va.gov.

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