Unlike violent hits in the NFL which can lead to a concussion requiring rest and recovery time, the effects from a single blast sustained in a military operation, equivalent to a typical improvised explosive device (IED), sets in motion chronic traumatic encephalopathy (CTE) and long-term brain impairment.
This recent study derives its conclusions from the examination of brain tissue (postmortem) from blast-exposed military service personnel and appears to confirm what has been reported in athletes with multiple concussions: abnormal deposits of the tau protein cause lesions which eventually kill brain cells.
To arrive at its conclusions, investigators compared the brains of four military servicemen, with known blast exposure, to four athletes who had sustained repetitive concussions, to four samples from individuals with a concussion-free history. The results of the analyses of CTE in the military personnel and the athletes were similar in many respects.
“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,” said Ann McKee, MD, who is the director of the Brain Banks for BU’s Alzheimer’s Disease Center and the Center for the Study of Traumatic Encephalopathy, both of which are housed at the Bedford VA Medical Center.
“The neuropsychiatric symptoms of CTE that have previously been associated with athletes diagnosed with CTE could also be attributed to military personnel who were exposed to blast,” added Lee Goldstein, MD, PhD, associate professor at Boston University School of Medicine.
One of the factors studied in the explosion of an IED was the blast wind, which can reach a speed of up to 330 miles per hour. This causes the head to move so forcefully that brain damage occurs. Taking this information, the investigators determined that immobilizing the head during a blast negated the learning and memory losses associated with CTE.
Clearly, compelling evidence is now emerging that explains what happens to the brain where violent forces are involved, providing direction for how to best diagnose, prevent, and treat head injuries.