May 17, 2012
Exposure To Blasts And Concussive Injuries Have Similar Brain Effects
Connie K. Ho for RedOrbit.com
Researchers from Boston University (BU) and the Veterans Affairs Boston Healthcare System recently found chronic traumatic encephalopathy (CTE) in the brain tissue of military service personnel who were exposed to blasts. The experiment showed that a single blast to an improvised explosive device (IED) resulted in CTE and long-term brain impairments related to the disorder. As well, blast wind from the IED resulted in traumatic brain injury (TBI) and long-term consequences that were similar to the head traumas that athletes have suffered.
CTE, a progressive neurodegenerative brain disorder, can only be diagnosed postmortem and has been seen in athletes who have suffered multiple concussions or subconcussive injuries. With CTE, there is an abnormal amount of protein deposits called tau that are neurofibrillary tangles, glial tangles and neuropil threads found throughout the brain. Brain cell death is the eventual result of the tau lesions. CTE has clinical features that are similar to TBI, such as the evidence of psychiatric symptoms as well as long-term memory and learning disabilities. TBI can affect around 20 percent of the 2.3 million men and women who have been exposed to blasts and have served in the military since 2001. Blast winds from an IED can go up to 330 miles per hour, which is stronger than any gust wind ever recorded on the planet.
"The force of the blast wind causes the head to move so forcefully that it can result in damage to the brain," said Dr. Lee Goldstein, a lead author in the study.
The study is the first to look at a series of postmortem brains from U.S. military personnel that have been exposed to a blast or have had a concussive injury. The research, recently published in Science Translational Medicine, was a collaborative effort by Goldstein, an associate professor at Boston University School of Medicine (BUSM) and Boston University College of Engineering, and Dr. Ann McKee, a professor at BUSM and a director of the Neuropathology Service for VA New England Healthcare System. They looked at the brain tissue samples from four military servicemen who had been exposed to blasts or concussive injuries; three young amateur football players and a wrestler that had suffered multiple concussive injuries; and four who had no prior exposure to blasts, concussive injuries, or neurological diseases.
The researchers found that the CTE neuropathology in the military servicemen who had been exposed to blasts was similar to the athletes who had prior history of concussive injuries.
"Our results showed that the neuropathology from blast exposure, concussive injury, or both were virtually indistinguishable from those with a history of repeat concussive injury," noted McKee, director of the Brain Banks for BU's Alzheimer's Disease Center and the Center for the Study of Traumatic Encephalopathy, in a prepared statement.
The two also worked with experts in blast physics, experimental pathology, and neurophysiology. The team observed that a blast felt by the military personnel could have the neuropathological and the behavioral evidence of CTE. Two weeks after the blast, the long term impairments in the brain function were already evident.
"Our finding of clear impairments in the ability to both learn and remember one month after a blast exposure leads us to wonder just how long-lasting these impairments are, and whether they can be prevented or rescued,” remarked Dr. Libor Velisek, a professor and director of the New York Medical College Developmental Epilepsy Laboratory and Behavioral Phenotyping Core Facility who assisted in the project, in the statement.
With these results, the researchers hope to continue their studies and examine how brain injuries can be prevented. They showed that immobilizing the head could help prevent disabilities related to learning and memory. This could be applied to assist in the development of strategies to treat and rehabilitate people who have been exposed to blasts in the past or have suffered concussive injuries.
"Our study provides compelling evidence that blast TBI and CTE are structural brain disorders that can emerge as a result of brain injury on the battlefield or playing field," concluded Goldstein in the statement. "Now that we have identified the mechanism responsible for CTE, we can work on developing ways to prevent it so that we can protect athletes and our military service personnel."