The U.S. Department of Defense identifies mild traumatic brain injury, or mTBI, as one of the signature injuries impacting veterans who served in Iraq and Afghanistan. Often associated with the blast of an improvised explosive device (IED) in the field, an mTBI is commonly diagnosed in concurrence with posttraumatic stress disorder, a separate condition triggered by the traumatic event.
A recent study suggests that 12 to 16 percent of all veterans involved in the Iraqi conflict have a history of mTBI and an estimated 13 to 17 percent of veterans return with a diagnosis of PTSD resulting from an injury.
One-third of all veterans with a TBI also suffer from PTSD. Since the time both conflicts began, medical researchers have studied the short- and long-term psychological and neuropsychological effects of PTSD and mild TBI as independent conditions.
Recently, researchers at the University of Kentucky published findings from a collaborative, multi-site study considering the collective, as well as individual, effects of mTBI and PTSD on psychological and cognitive functioning.
The results, which are scheduled to appear in The Journal of Neurotrauma, suggest veterans suffering from both conditions have poorer cognitive and psychological outcomes than veterans diagnosed with only one of the conditions.The research also raises the possibility that mTBI results in persistent but mild cognitive challenges for some veterans.
Dr. Walter High, an adjunct associate professor in the UK Department of Physical Medicine and Rehabilitation, Neurosurgery and Psychology, and researchers at the University of Kentucky Department of Psychology, worked with veterans at the Lexington Veterans Affairs Hospital on the UK campus to conduct a series of neuropsychological tasks measuring their cognitive function.
Participating veterans were classified as mTBi only, PTSD only, or both mTBI and PTSD. The tests evaluated cognitive processing speed, IQ, verbal memory, psychological distress and more. Participants were also grouped according to their similarities in IQ, age and other characteristics.
“Most previous studies have not adequately separated out the cognitive effects due to mTBI from the cognitive effects due to PTSD,” High said. Our study is relatively unique because it includes a comparison group of veterans with PTSD only. This is extremely important because the effects of mTBI and PTSD can be very similar.
The inclusion of a group of veterans with both mTBI and PTSD also allowed us to look at the interactive effects of these conditions." While research has suggested that infrequent isolated concussions (mTBI) have minimal long-term effects, PTSD has been linked to long-term impairment of psychological functioning and memory loss.
The set of data was distinctive from other research trials on long-term effects of mTBI in that the researchers were able to rule out confounding variables influencing cognitive processing. Through an analysis of the data, High and UK doctoral student Hannah Combs, who published the paper as her master's degree thesis, found small decrements in information processing efficiency, attention and memory that could be attributed to the mTBI.
David Berry, Ph.D, professor in the Department of Psychology, was a key collaborator in the study helping to characterize the validity of veteran performances and chairing Combs' master’s committee. "We feel we know this phenomenon, but this shows there is more to it than we originally expected," Combs said of the effects of mTBI.
"If a veteran is complaining about these issues, there's a good chance they are true." High said the decrements attributable to mTBI are small and not disabling. Veterans can overcome the mild cognitive impairment caused by mTBI with proper education about mTBI and therapies. The study will help guide psychologists implement proper cognitive therapies for injured veterans suffering from these mild effects.
“The take-home message is that we need to validate to the veteran that the problems they are experiencing are real, but to reassure them that their cognitive abilities are within normal limits and they can still be successful,” High said. “There are strategies to rehabilitate and exercise their memory.”
Researchers at UK, the Northwestern University Feinberg School of Medicine, and Southern Arizona Department of Veteran Affairs collaborated on the study. One-third of the study’s participants represented patients at the Lexington Veterans Affairs Hospital. The study was supported by a grant from the U.S. Department of Veterans Affairs.