(Bloomberg) — David Hay was almost out of ammunition when a rocket-propelled grenade exploded in the turret of his Centurion tank in the rubber plantation village of Binh Ba, Vietnam, spraying shrapnel into the 21-year-old radio operator's body.
That was 46 years ago, and while the flesh-wounds healed within weeks, Hay had nightmares and bouts of depression for decades. Now, he and hundreds of other Vietnam veterans are helping doctors try to trace pathways in the brain that may connect the trauma he suffered with the development later in life of one of the world's fastest-growing and most debilitating diseases: Alzheimer's.
For decades, dementia-causing conditions like Alzheimer's were a mystery, illnesses that couldn't be diagnosed for sure except at post-mortem. The development of advanced PET scans, combined with new tracer dyes means that doctors can now follow subtle biological routes in the brain and spinal fluid. That could explain how and why physical and psychological wartime traumas can double the risk of such conditions.
"Vietnam veterans are getting to an age now where we should be picking up changes in those people who are going to develop Alzheimer's," said Christopher Rowe, director of molecular imaging research at the Austin Hospital in Melbourne, who is leading the Australian arm of the research.
Football concussions
The findings will offer insights into what causes dementia, cases of which are projected to almost double every 20 years. They could shed light on the long-term effects of assaults on the brain — whether sustained in battle, in a car wreck or on the football field, said Michael Weiner, professor of radiology at the University of California, San Francisco School of Medicine, who's leading the study.
"It's long known that there's an association of head injury with Alzheimer's disease," Weiner said. "But no study has been done with biomarkers to establish the risk."
About 2 percent of Americans live with disabilities caused by a traumatic brain injury, amounting to $77 billion in costs, according to the U.S. Centers for Disease Control and Prevention. It was associated with about 2.5 million emergency department visits, hospitalizations, or deaths in the U.S. in 2010.
The new study, funded by the U.S. Department of Defense, is looking for early signs of disease in healthy veterans who, like Hay, experienced post-traumatic stress disorder, as well as those who suffered a physical brain injury. The data is compared with results from veterans who had neither form of injury. About 125 men have been enrolled so far — about a quarter of the number sought in the U.S., Canada and Australia.
Diagnostic tools
The tests are a sign of the growing demand in developed nations for advanced equipment and medical techniques that can diagnose ailments before they become difficult to treat.
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