.Explosions cause brain damage through head movement
Soldiers experience high-pressure shock waves and immense forces during explosions in the field, but research suggests brain trauma is caused merely by the sudden head movements.
It has been unclear whether trauma from explosions is caused through high-pressure shock waves penetrating the skull, or through another mechanism. Now a team of researchers from Boston University have performed post mortems on soldiers to establish how traumatic brain injury occurs during explosions.
Many blast victims develop symptoms consistent with chronic traumatic encephalopathy (CTE), a degenerative brain disease that can cause memory problems, depression and learning difficulties. However, CTE is usually caused by repeated concussions such as those experienced by American football players – not one-off blasts.
"The damage in football players has been linked to acceleration forces due to head impact," explains Robin Cleveland, a medical engineer 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."
Cleveland and his colleagues performed a post mortem analysis of brains from four soldiers who had experienced blasts. They compared the brains to those of American footballers and a wrestler who all had a history of repetitive concussive injury, as well as with a person with no brain trauma. They found firm evidence of CTE, as indicated by abnormal deposits of the protein tau in the brain of the soldiers, which was indistinguishable from CTE in the athletes.
Shock force
The team also sought to establish the mechanics behind brain trauma. They exposed mice to shock forces equivalent to humans subjected to improvised explosive devices (IEDs), and measured head oscillations using high-speed cameras.
Mice that had experienced the blast took longer to navigate a maze than unexposed mice, and they showed signs of memory retention problems. Further examination revealed the presence of tau deposits within their brains consistent with CTE.
When their heads were restrained to prevent movement, though, no brain damage or memory problems were observed. "It was the movement of the head, not the passage of the shockwave, that produced the damage," explains Cleveland.
The finding may impact the way that we protect troops. "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."
Jennifer Wild, at the University of Oxford, is impressed. "It's a well-conducted study, and it's good to finally have definitive research about the effects of explosion on brain function," she says.
Wild also suggests the results could have wider implications. "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 explains. "This finding could help reduce the incidence of PTSD in soldiers."
NewScientist
It has been unclear whether trauma from explosions is caused through high-pressure shock waves penetrating the skull, or through another mechanism. Now a team of researchers from Boston University have performed post mortems on soldiers to establish how traumatic brain injury occurs during explosions.
Many blast victims develop symptoms consistent with chronic traumatic encephalopathy (CTE), a degenerative brain disease that can cause memory problems, depression and learning difficulties. However, CTE is usually caused by repeated concussions such as those experienced by American football players – not one-off blasts.
"The damage in football players has been linked to acceleration forces due to head impact," explains Robin Cleveland, a medical engineer 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."
Cleveland and his colleagues performed a post mortem analysis of brains from four soldiers who had experienced blasts. They compared the brains to those of American footballers and a wrestler who all had a history of repetitive concussive injury, as well as with a person with no brain trauma. They found firm evidence of CTE, as indicated by abnormal deposits of the protein tau in the brain of the soldiers, which was indistinguishable from CTE in the athletes.
Shock force
The team also sought to establish the mechanics behind brain trauma. They exposed mice to shock forces equivalent to humans subjected to improvised explosive devices (IEDs), and measured head oscillations using high-speed cameras.
Mice that had experienced the blast took longer to navigate a maze than unexposed mice, and they showed signs of memory retention problems. Further examination revealed the presence of tau deposits within their brains consistent with CTE.
When their heads were restrained to prevent movement, though, no brain damage or memory problems were observed. "It was the movement of the head, not the passage of the shockwave, that produced the damage," explains Cleveland.
The finding may impact the way that we protect troops. "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."
Jennifer Wild, at the University of Oxford, is impressed. "It's a well-conducted study, and it's good to finally have definitive research about the effects of explosion on brain function," she says.
Wild also suggests the results could have wider implications. "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 explains. "This finding could help reduce the incidence of PTSD in soldiers."
NewScientist
posted by madtom at 9:22 PM
1 Comments:
The brain is one of the most delicate organs of the human body and as such, it can be incredibly vulnerable to serious damage in the event of a head injury. Depending on the injuries sustained, the resulting damage can affect one or many regions of the brain with 5% of cases being classed as a moderate form of injury and 10% as severe. Patients in the latter can be left with a debilitating and life-long disability.
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