Mild brain trauma may raise long-term Alzheimer's risk |
Posted 12/8/2010 Updated 12/8/2010
by Cheryl Pellerin
American Forces Press Service
12/8/2010 - WASHINGTON -- Improvised explosive devices and multiple deployments to Iraq and Afghanistan are boosting the incidence of mild traumatic brain injury, a condition that some early studies indicate may increase a person's future risk for Alzheimer's disease, a researcher said Dec. 7.
Dr. Elaine Peskind spoke at the 3rd Annual Trauma Spectrum Conference held today and yesterday at the National Institutes of Health in Bethesda, Md.
The conference -- sponsored by the Defense Centers of Excellence for Psychological Health and Traumatic Brain Injury, the National Institutes of Health and the Department of Veterans Affairs -- targeted emerging research on polytrauma, recovery and reintegration for servicemembers, veterans and their families.
Traumatic brain injury severe enough to cause loss of consciousness -- from a sports concussion, an automobile accident or an IED -- "is the best-established environmental risk factor for Alzheimer's, the late-life dementing disorder occurring in up to 50 percent of people over age 85," she said.
Dr. Peskind is a geriatric psychiatrist and a research professor of psychiatry and behavioral sciences at the University of Washington School of Medicine in Seattle.
She also is a Veterans Administration doctor who is credentialed at Washington's Joint Base Lewis McChord. There, since 2007, she and a colleague have conducted a clinical trial to evaluate the drug Prazosin for active-duty soldiers with post-traumatic stress disorder.
It was during the Lewis McChord study that Peskind noticed the link between PTSD and mild traumatic brain injury, or mTBI, and memory problems.
During study visits, she noticed that soldiers regularly took little notebooks out of their shoulder pockets and wrote down everything she said -- so they would not forget, they told her. And study coordinators had to call and remind the soldiers to come to their appointments.
Dr. Peskind, who once considered mTBI a problem of rehabilitation rather than mental health, called it a "classic light bulb moment."
"I said, wow, maybe we do have a problem here," she added, "and I became very interested in TBI research."
The nature of the wars in Iraq and Afghanistan is contributing to the mTBI problem, she said.
"As of this month, something in the vicinity of 2 million soldiers and Marines have been deployed to the wars in Iraq and Afghanistan -- OIF and OEF -- and nearly 800,000 have been deployed more than once," she said.
And the weapon of choice for insurgents in both war zones is a range of improvised explosive devices, she said.
"The estimate of the number who returned with symptomatic mild traumatic brain injury due to blast exposure has varied from the official VA number of 9 percent officially diagnosed with mTBI to over 20 percent," she said, "and I think, ultimately, it will be higher than that."
Compared with the wars in Vietnam and Korea, she said, a significant improvement in body armor and battlefield medicine have altered the ratio of wounded to killed in battle from 4 to 1 in previous wars to 10 to 1 today.
"So we have a lot more soldiers and Marines and other servicemembers surviving blast exposure," Dr. Peskind said.
News reports highlight the damage that can result from head injuries experienced by some collegiate and professional football players, she said.
John Grimsley, a former Houston Oilers linebacker, developed a dementing disorder in his mid-40s, Dr. Peskind said. After his death at age 45 in 2008 from an accidental gunshot wound, a brain autopsy showed multiple neurofibrillary tangles, one of the two major indicators of Alzheimer's disease.
Similar cases include Cincinnati Bengals wide receiver Chris Henry, who died in a 2009 accident at age 26, and 21-year-old University of Pennsylvania defensive end Owen Thomas, who committed suicide in 2010.
Autopsies of both young brains showed neurofibrillary tangles, she said.
"There is a growing concern that multiple concussive and subconcussive events -- you know, head injuries -- may set in motion pathogenic processes that may later emerge as these neurodegenerative dementing disorders," Dr. Peskind said.
But for servicemembers with mTBI, the concern is that mTBI could eventually lead to Alzheimer's disease later in life, she said.
"There has been lively controversy regarding the etiology, course and treatment of the persistent post-concussive somatic, cognitive and behavioral symptoms in OIF/OEF veterans following a blast exposure and TBI," Dr. Peskind said.
An epidemiologic study in active-duty soldiers at Walter Reed found that many of the chronic post-concussive symptoms, except headache, were more correlated with PTSD and depression than with mTBI, she added.
"But I and many other skilled clinicians are pretty well convinced that for warfighters these chronic, post-concussive symptoms following a blast concussion and TBI reflect real but reasonably subtle persistent brain damage," Dr. Peskind said.
To find out whether the chronic symptoms represent structural or functional brain changes, Dr. Peskind said she and her colleagues are involved in an ongoing study that involves four different kinds of brain imaging technologies and multiple physiological and neuropsychological tests.
In preliminary results of the work, which she called a "snapshot in time," Dr. Peskind said the imaging is beginning to show a "pattern of functional deficits [that] is somewhat reminiscent of the very, very earliest changes seen in Alzheimer's disease."
But, she added, "caution is needed ... We need more data, we need more analysis and of course replication [of these results] by other [research] groups is needed ... We really need to figure out what the long-term risk is for this group of veterans."