A new study conducted by military scientists may finally explain how the blast force from explosives manages to injure the brains of U.S. servicemen deployed in combat zones.
Neuropathologist Dr. Daniel Perl and his colleagues at the Uniformed Services University of the Health Sciences (USU) in Maryland set out to determine how shockwaves from explosives are linked to the development of a mental condition known as post-traumatic stress disorder (PTSD).
They examined scars in the brains of eight servicemen who survived bomb blasts during their tour of duty but eventually died within four to nine days following the trauma. All of them were exposed to blasts caused by combat explosives, but only five of them were diagnosed with PTSD.
The researchers saw that the damage the soldiers sustained mostly centered on the parts of the brain typically associated with sleep, memory and cognitive function.
One of the soldiers the team examined was a 45-year-old veteran who had been exposed to a number of shockwaves throughout his 25 years in the service. He had committed suicide after having been diagnosed with anxiety, depression and PTSD, but subsequent MRI scans of his brain taken when he was still alive revealed that he had no abnormalities.
Perl explained that routine MRIs for explosion-related traumatic brain injuries often show no abnormalities on the brain of soldiers.
However, many of these servicemen continue to report about debilitating symptoms associated with structural brain damage such as headaches, memory problems, sleep disturbance, depression and even erratic behavior.
Perl said that because there isn't enough information available on the pathophysiology of the injury, it has been difficult for doctors to properly diagnose and treat these "invisible wounds" on the soldiers.
Potential Factors Contributing To The Development Of PTSD
According to the researchers, the damage seen on the brain areas linked to PTSD may increase the likelihood of soldiers exposed to blasts to develop the condition.
The researchers saw a unique yet consistent pattern in the scarring on the brain of five of the servicemen who survived for over six months following their trauma. The damage was found on areas crucial for sleep, memory, thinking and other vital brain functions.
They identified significant scarring on a number of brain structures linked to PTSD.
Three of the servicemen who died within four to 60 days after their exposure to explosive blast also showed a similar scarring pattern in the same regions of their brain. This suggests that the pattern of damage may likely have been caused by the explosion itself.
Soldiers who sustained other forms of brain injury, such as those from contract sports or vehicular accidents, showed a different type of scarring.
Perl said they were not able to find similar brain scarring from these controls such as those on the blast cases. This means the unique pattern they saw in the eight soldiers they examined were most likely caused by their exposure to high explosives.
The findings of the Uniformed Services University of the Health Sciences study are featured in the journal The Lancet Neurology.
