Study aims to track long-term effects of traumatic brain injury on service members
Biologist Rebecca Jimenez infuses gel samples with fluorescent properties in order to discover technology solutions to protect soldiers. (Photo by David McNally)
By Rindi White
Traumatic Brain Injury, or TBI, is significant concern of the U.S. military. Nearly 20 percent of the 2.5 million service members and veterans who deployed to Iraq and Afghanistan are known to have sustained at least one TBI; most of those injuries have been classified as mild.
However, a mild TBI can still have long-term consequences. Many mild TBIs go undocumented. Most resolve themselves within a few weeks or months, but some people with even mild TBIs report long-term effects on their thinking ability, memory, mood and focus. Other symptoms include headaches and vision and hearing problems.
A new federal study is enrolling at least 1,100 service members and veterans who fought in Iraq or Afghanistan to learn more about mild traumatic brain injury and how it can be best evaluated and perhaps prevented and treated, according to a story in the U.S. Department of Veterans Affairs’ VA Research Currents blog.
Researchers hope to follow the study participants for 20 years or more to gain a better understanding of the long-term neurological effects of mild TBI and other deployment-related conditions. One significant concern is whether mild TBI increases the risk for early dementia.
The study is being done through the Chronic Effects of Neurotrauma Consortium, or CENC, funded through the National Research Action Plan in 2013. A second consortium will focus on Post Traumatic Stress Disorder, also a “signature” injury of the wars in Iraq and Afghanistan. The two studies received $107 million in funding total and involve broad collaborations between researchers from the VA, the Department of Defense, other federal agencies and academia.
Leading the study is Dr. William Walker, a TBI expert at the Richmond VA Medical Center and Virginia Commonwealth University, where the CENC is based. According to the VA, Walker said the long-term study is one of the most comprehensive TBI projects to date. At the center of the study is a comprehensive interview that study volunteers undergo when they begin their participation. The team asks not only about any mild TBI events that may have happened in combat zones but also those that might have happened earlier in their life or after military service.
“The cornerstone of this study is that we’re doing a very intensive standardized interview to get at all of the lifetime potential concussive events,” Walker said. “Many of these individuals have had multiple concussions throughout their lifetimes. We’re looking at it from an epidemiologic standpoint of lifetime exposures.”
Walker explained that participants will be asked about whatever head impacts they can recall, whether from falling off a swing set as a child and hitting their head or an automobile accident with a whiplash injury or a blast that went off nearby while on military deployment. Each event is being catalogued and investigated to find out whether it was a TBI.
Participants will also undertake a variety of exams, including: brain scans, eye-movement tracking, computerized balance tests, neurophysical tests, blood tests and more. Volunteers will come to the clinic about once every five years for the array of tests, which will take about eight hours. On the non-testing years, participants will have a 45-minute phone assessment with a study team member to test for memory and concentration, along with other measures.
Eight sites are enrolling study participants: the National Center for the Intrepid at Fort Belvoir, Virginia; and VA centers in Boston; Minneapolis; San Antonio; Houston; Portland, Oregon; Richmond, Virginia; and Tampa, Florida.
Researchers hope to learn how the circumstances of an injury make a difference in long-term outcomes. For example, are blast-related injuries more harmful than blunt injuries? Are the effects of multiple TBIs more harmful than a single one?
Genetics will also be examined. If a veteran has the AOP E4 gene variant, which heightens Alzheimer’s risk, will that person have more harmful long-term consequences from a TBI? Do changes in the thickness in the brain’s cortex or abnormalities in the brain’s white matter spell different outcomes for individuals with TBI?
And perhaps most importantly, Walker said, is the long-term focus, which should help researchers understand more clearly the link between TBI and late-in-life neurodegenerative conditions such as Alzheimer’s and chronic traumatic encephalopathy, or CTE. CTE has recently been in the news because of its link to concussions among athletes in sports such as football, boxing and hockey.
“One of the main impetuses for the study is the risk of, and the fear of, CTE,” Walker said. “To fully capture that incidence, we feel we need at least 20 years. But we would like to continue the study as long as we have resources available to do so and as long as a significant number of the individuals we enroll remain living.”
Other studies at work
At Aberdeen Proving Ground, Maryland, U.S. Army researchers are studying the physiological effects of blast pressure on the brain to discover technology solutions to better protect soldiers.
Scientists at the Army Research Laboratory, or ARL, are developing nanomaterials aimed at helping understand how the brain responds when soldiers are exposed to a blast.
The scientists, in cooperation with the DOD Blast Injury Research Program Coordinating Office and U.S. Army Medical Research and Materiel Command, have developed a fluorescent, gel substance that mimics the texture and mass of the human brain. According to a story from the ARL, the goal is to show the scale of damage to the brain under pressure conditions that soldiers encounter in combat or training.
“We develop materials solutions that enable us to understand the mechanisms of damage at the cellular level,” said Dr. Shashi P. Karna, ARL nanofunctional materials senior research scientist. “What are the mechanisms by which the blast pressure waves travel to the brain?”
The lab is also creating materials that will enable researchers to see details that have never been recorded before. Using nanotechnology, scientists will see what happens to the brain at a cellular level during an explosion.
“We have nanomaterials that are highly robust so that in real time, when the blast occurs, it will be possible to image the effects like an MRI, but with fluorescence,” Karna said. “Colors will show the motion of the cells.”
The laboratory has built a partnership with the Japanese Ministry of Defense, which is working on the same problem. In December 2016, Japanese medical researchers visited Maryland for an update.
“The Japanese are addressing this through a medical technique … to look at the oxygen level, for example in the tissue,” Karna said. “They also look at the cortical depressant. When the blast waves hit the brain, there is fluctuation in the blood circulation level. So they look at these physiological systems to assess what is affected by the blast.”