Not all concussions are caused by blows to the head, like the type typically incurred in sports, falls or auto accidents. Concussion also can be caused by explosions.
Concussion is caused when the brain bounces or twists inside the skull, leading to chemical changes inside the brain and stretching and damaging of brain cells. An explosion can cause a concussion by creating rapid changes in air pressure.
A new study has found that how the concussion occurred – whether by a blow or a blast – can dictate changes in brain activity and behavior later.
The researchers found that blast-related concussions caused a different pattern of brain activity than those caused by a blow to the head. The findings are the first to demonstrate these differences in humans.
“The causes of the injury can make a very important difference in the way that’s expressed behaviorally and also in the way the brain is altered by the traumatic brain injury,” says Stephen Rao, PhD, a neuroscientist who helped lead the study.
The study could have important implications for military personnel. Fifteen percent to 28 percent of military personnel serving in Afghanistan and Iraq suffered concussions, the study says. Of those, 50 percent to 79 percent received that injury as a result of a blast from an improvised explosive device.
Researchers say the study suggests a blast-related concussion could result in loss of the ability to control impulses and could lead to behaviors such as gambling or heavy drinking.
In the past, such behavior changes may have been attributed to post-traumatic stress disorder, Dr. Rao says.
Nearly 100 military personnel and civilians took part in the study. Dr. Rao and his research team asked the participants to perform a task that measured their ability to stop or suspend an intended or initiated action. At the same time, researchers recorded the participants’ brain activity using a magnetic resonance imaging (MRI) scanner.
More studies are needed, but knowing how a patient with a concussion was injured could result in improved, more specialized treatment, Dr. Rao says.
“Because we are showing differences in the way the brain is affected by blast versus mechanical injuries, it is conceivable that the types of rehabilitation efforts and the types of rehabilitation strategies may be very different for the two types of brain injuries,” Dr. Rao says.
The findings were published today in Journal of Neurotrauma.