A new study sheds some light on the previously “invisible” brain injuries suffered by military members exposed to high-explosive blasts.
The findings show that the brains of deceased military personnel who had been exposed to high-explosive blasts exhibit a distinct and previously unseen pattern of scarring that differs from other types of head injury, according to the new research published online in the journal Lancet Neurology.
The findings help neuroscientists better understand the neurological and behavioral symptoms suffered by blast victims.
“Those areas of the brain, damaged by blast, suggest that they may be correlated with the symptoms displayed by those who sustained a traumatic brain injury, or TBI. This scarring pattern also suggests the brain has attempted to repair brain damage from a blast injury,” said Dr. Daniel Perl, study senior author and professor of Neuropathology at the Uniformed Services University of the Health Sciences in Maryland.
Military members sustaining a TBI have often reported suffering from persistent post-concussive symptoms, which include a mixture of both neurologic symptoms and behavioral disturbances.
“These can include problems such as headaches, difficulty concentrating, sleep disorders, memory problems, depression and anxiety. Despite these prominent symptoms, conventional neuroimaging for mild TBIs typically has not allowed providers to ‘see’ brain abnormalities, leading this to be considered the ‘invisible wound,’” said Perl.
To gain a better understanding of these specific types of brain injuries, researchers from the Uniformed Services University of the Health Sciences (USU), the Department of Defense Joint Pathology Center and the University of Colorado’s School of Medicine, examined brain tissue specimens of deceased service members, who had been exposed to a high explosive blast injury and had suffered several persistent symptoms.
These included the brain tissues of five service members who had suffered from remote blast exposures, as well as the brain tissues of three service members who died shortly after severe blast exposures. The researchers compared these results with brain tissues from civilian (non-military) cases, including five with remote impact TBIs, and three cases with no history of a TBI.
The findings show that the brain scarring from explosive blasts involves the portion of tissue immediately beneath the superficial lining of the cerebral cortex — where the gray and white matter meet — as well as in vital areas close to cavities filled with cerebrospinal fluid.
“This changes the earlier paradigm of ‘battle injury’ and demonstrates unique and specific biological changes in brains due to these injuries,” said Perl, who also serves as director of USU’s Center for Neuroscience and Regenerative Medicine TBI Brain Tissue Repository.
“This publication sheds some light, for the first time, into the nature of the persistent behavioral/ neurologic issues being reported in numerous service members who have been exposed to high explosives.”