You don’t have to sustain a head injury from a hit to the head, it can also come from sudden head movement caused by whiplash, or even a high-pressure shock wave from an explosion.

Soldiers in the field, either in battle or in training, are subject to high-pressure shock from explosions. Construction workers can sustain head injuries when exploding a building or setting off charges to clear a worksite. At the time they not realize it, but more and more evidence is coming forth to prove this may be happening.

According to a team of researchers at Boston University, many blast victims can develop symptoms consistent with a degenerative brain disease called chronic traumatic encephalopathy (CTE), that can cause memory problems, depression and learning disabilities. CTE previously was thought to be caused by repeated concussions, such as those experienced by football players in the NFL, not from one-time explosions from a blast.

What they did not understand was if the brain trauma could be caused by the high-pressure shock waves penetrating the skull, or was it coming from some other source. It wasn’t until the researchers performed autopsies on soldiers were they able to establish how the brain injury occurred from the blasts.

“The damage in football players has been linked to acceleration forces due to head impact,” explains medical engineer Robin Cleveland, who worked on the project at Boston University before moving to the University of Oxford. “Our goal was to see if the same mechanism was responsible for blast injury.”

A post-mortem evaluation was performed by Cleveland and his colleagues on the brains of  four soldiers who had been impacted by explosions. They compared the brains of the soldiers to those of American football players and wrestler who had histories of repeated concussions, as well as those with no head trauma. They found abnormal deposits of the protein tau in the brain of the soldiers that were no different than that of the athletes with concussions. This was concrete evidence of CTE to the researchers.

Their research also was trying to establish the mechanics behind brain trauma. They worked with mice to replicate the shock forces in the humans by using high-speed cameras. The mice that experienced the blast took longer to navigate the maze than the unexposed mice did, and showed memory problems as a result of the exposure. The presence of tau deposits in the brain of the mice in the explosion was consistent with that of CTE.

When the heads of the mice were protected and restrained to protect their head movement, no brain damage or memory problems occurred. “It was the movement of the head, not the passage of the shockwave, that produced the damage,” explains Cleveland.

The implications of the study may help those in the military be protected from head trauma. “In the past, the main effort has focused on designing helmets to prevent shock-wave transmission into the head,” says Cleveland. “But based on our results, providing resistance to head motion would be far more effective.”

The study impressed Jennifer Wild from the University of Oxford, who said, “It’s a well-conducted study, and it’s good to finally have definitive research about the effects of explosion on brain function.”  She suggests there could be wider implications from this study. “Those suffering traumatic brain injury are at increased risk of developing post-traumatic stress disorder and respond less well to conventional treatments for it,” she says. “This finding could help reduce the incidence of PTSD in soldiers.”



About the author:

Ron White is a two-time U.S.A. Memory Champion and memory expert. As a memory speaker he travels the world to speak before large groups or small company seminars, demonstrating his memory skills and teaching others how to improve their memory, and how important a good memory is in all phases of your life.



New Scientist – Explosions cause brain damage through head movement: