New DoD-funded study to track Alzheimer's in Veterans with head injuries
Tracking brain outcomes for Vietnam Vets-Marines riding atop an M-48 tank cover their ears as a 90mm gun fires during a road sweep in Vietnam. A VA-led study is exploring whether Vietnam Veterans who experienced traumatic brain injury or posttraumatic stress disorder are more likely to develop dementia as they age. (Photo: National Archives)
A new study funded by the Department of Defense and involving VA researchers will seek to confirm whether Vietnam Veterans with traumatic brain injury or posttraumatic stress disorder are at higher risk for Alzheimer's disease as they age.
Past studies clearly point to head injury as a risk factor for dementia. "We've known for many years that TBI is a risk factor for Alzheimer's," says Michael Weiner, MD, the study's lead investigator. "If you've been knocked unconscious—say you fell out of a tree when you were a kid, or you suffered a concussion playing football—you're at much greater risk for Alzheimer's disease in your 70s than if you were never knocked unconscious."
Among other research, a study published in Neurology in 2000 by Brenda Plassman, PhD, a dementia researcher at Duke University and frequent collaborator with VA investigators, tracked the outcomes of World War II Navy and Marine Veterans who had been hospitalized during their service with non-penetrating head injuries. Moderate and severe injuries were strongly linked to an increased risk for Alzheimer's and dementia later in life, although the researchers said they couldn't rule out the possibility that other factors affected the trend.
The evidence tying PTSD to Alzheimer's is less robust, but some studies suggest a connection. For example, PTSD, like Alzheimer's, is associated with reduced volume in the hippocampus, an area of the brain crucial for forming new memories.
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The new $6.5-million study is a spin-off of the main Alzheimer's Disease Neuroimaging Initiative (ADNI), also led by Weiner. The DoD initiative will take advantage of the methods and research network developed through ADNI.
Says Weiner: "We're using all the methods developed in ADNI. We're diagnosing Alzheimer's with biomarkers—amyloid imaging, lumbar punctures, MRIs—as well as neuropsychological tests and medical exams."
Weiner's team at the San Francisco VA is scanning military and VA databases for prospective participants and reaching out to them with phone calls and brochure mailings. The researchers aim to do an initial interview with 1,000 Veterans, and identify at least 400 who will complete clinic visits and all the assessments.
To learn more, visit http://www.adni-info.org/ADNIDOD.aspx.