By Brenda L. Mooney
SALISBURY, NC – Veterans exposed to explosions during deployment but not reporting common symptoms of traumatic brain injury (TBI) could have similar damage to the brain’s white matter, according to a new study.
In a small study published recently in the Journal of Head Trauma Rehabilitation, researchers at the VA and Duke University School of Medicine point out that the full extent of brain injury from explosions cannot be determined by symptoms alone.1
The study is the latest to suggest that subconcussive events have an effect on the brain, which is especially significant because so many veterans of recent military conflicts in Iraq and Afghanistan have had exposure to explosive forces from bombs, grenades and other devices.
According to past research, as many as 20% of the 2.3 million troops deployed to Iraq and Afghanistan since 2001 could have suffered a TBI as a result of exposure to improvised explosive devices (IEDs) and other incendiary weapons.
“Similar to sports injuries, people near an explosion assume that if they don’t have clear symptoms — losing consciousness, blurred vision, headaches — they haven’t had injury to the brain,” said senior author Rajendra A. Morey, MD, associate professor of psychiatry and behavioral sciences at Duke University School of Medicine and a psychiatrist at the Durham, NC, VAMC. “Our findings are important because they’re showing that, even if you don’t have symptoms, there may still be damage.”
The findings are based on 45 volunteer veterans who served in the military after September 2001 and who had primary blast exposure without external injuries from direct hits to the head. Researchers from the W.G. (Bill) Hefner VAMC in Salisbury, NC, divided the veterans into three groups: those with a history of blast exposure with symptoms of TBI; those with a history of blast exposure without symptoms of TBI; and those without blast exposure.
To measure injury, the researchers used Diffusion Tensor Imaging (DTI), which measures the flow of fluid in the brain. Injured fibers allow the fluid to diffuse while, in healthy white matter, fluid moves in a directional manner, suggesting that the white matter fibers are intact.