November 10, 2009
Progress Made In Detecting PTSD Signs On Brain Scans
Veterans of the Iraq and Afghanistan wars are benefiting from powerful scans that allow doctors to see just how the brain changes in soldiers with post-traumatic stress disorder and concussion-like brain injuries, The Associated Press reported.
The procedures may lead to easier diagnosis for patients - civilian or military - who struggle to get help for these largely invisible disorders.
Now that scientists are learning where and how to look for such injuries, these problems that are too often shrugged off as "just in your head" do, in fact, show physical signs.
Dr. Jasmeet Pannu Hayes of Boston University, who is helping to lead that research at the Veterans Affairs' National Center for PTSD, said that just putting a real physical marker on the brain encourages more people to seek care for these types of injuries.
PTSD symptoms are common in up to one in five U.S. veterans from the long-running combat in Iraq and Afghanistan. An equal number of soldiers are believed to have suffered traumatic brain injuries, or TBIs - most that don't involve open wounds but hidden damage caused by explosion's pressure wave.
A number of these TBIs are considered similar to a concussion because symptoms may not be apparent immediately. But many soldiers are exposed multiple times, especially if there's little time between assaults.
A recently retired Marine whom Hayes identifies only as Sgt. N described the injuries by saying his brain had been rattled. He estimates he felt some 50 to 60 explosions as part of an ordnance disposal unit.
Hayes tracked how water flows through tiny, celery stalk-like nerve fibers in Sgt. N's brain and found otherwise undetectable evidence that those fibers were damaged in a brain region -"“ explaining his confusion and memory problems.
The process, called diffusion tensor imaging, is a noninvasive technique that merely adds a little time to a standard MRI scan.
During the scan, water molecules constantly move, bumping into each other and then bouncing away. Measuring the direction and speed of that diffusion in nerve fibers can reveal whether the fibers are intact or damaged. Those fibers are sort of a highway along which the brain's cells communicate. The brain's work becomes increasingly interrupted the bigger the gaps become.
Hayes told a military medical meeting last week that Sgt. N's brain is very different, as his connective tissue had been largely compromised.
Dr. James Kelly, a University of Colorado neurologist tapped to lead the military's new National Intrepid Center of Excellence, said there's a remarkable overlap of symptoms between those brain injuries and PTSD.
He said that headaches are a hallmark of TBI while the classic PTSD symptoms are flashbacks and nightmares. Meanwhile, both tend to cause memory and attention problems, anxiety, irritability, depression and insomnia -"“ meaning the two disorders share brain regions.
Hayes said they could now measure how some of those regions go awry during PTSD, where patients feel like they're re-living a trauma instead of understanding that it's just a memory.
She explained that the brain processing system that includes the amygdala - the fear hot spot - becomes overactive, while other regions important for attention and memory that usually moderate our response to fear, are tamped down.
Hayes said the good news is that the neural signal is not permanent and can change with treatment.
They performed MRI scans while patients either tried to suppress their negative memories, or followed PTSD therapy and changed how they thought about their trauma. They discovered that when people followed the PTSD therapy, their fear-processing region quickly cooled down.
Experts say at least a quarter of a million Americans will develop PTSD at some point in their lives and anyone can develop it after a terrifying experience.
More research is needed for the scans to be used in diagnosing either PTSD or a TBI.
However, another MRI-based test can spot lingering traces of iron left over from bleeding, thus signaling a healed TBI. Kelly said that if the brain was hit hard enough to bleed, then more delicate nerve pathways surely were damaged.
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