Study Links PTSD to Hidden Head Injuries Suffered in Combat
A study from the University of Rochester Medical Center suggests that very subtle brain injuries sustained during combat—injuries so slight they are detectable only with advanced imaging—may increase the risk of developing post-traumatic stress disorder (PTSD). This finding has implications for how clinicians evaluate and treat veterans whose symptoms may overlap between mild traumatic brain injury (mild TBI) and PTSD.
The researchers examined 52 U.S. veterans from western New York who served in combat zones between 2001 and 2008. On average, the assessments occurred about four years after the veterans’ final deployments. Investigators collected detailed histories of blast exposure, concussion events, and combat-related stress, and they evaluated each veteran for PTSD symptoms. In addition to conventional magnetic resonance imaging (MRI), the team used diffusion tensor imaging (DTI), a more sensitive scan that can reveal axonal injury—damage to the nerve fibers that connect different regions of the brain.
Results showed that 30 of the 52 veterans reported at least one mild traumatic brain injury during deployment, and seven reported multiple incidents. Blast exposure was common: roughly 60 percent of participants experienced one or more explosive blasts. All veterans in the study had at least one PTSD symptom, and 15 met diagnostic criteria for PTSD.
Importantly, the extent of axonal injury identified on DTI correlated with the severity of PTSD symptoms. A smaller group—five of the 52 veterans—had abnormalities visible on standard MRI scans; those individuals tended to have more severe PTSD than veterans with normal MRIs. By contrast, the clinical diagnosis of mild TBI based on reported loss of consciousness or amnesia did not reliably predict PTSD severity.
These findings suggest that subtle brain injury can occur without the classic clinical signs used to diagnose mild TBI. In other words, an individual might sustain axonal damage that does not cause obvious loss of consciousness or memory loss but still increases vulnerability to psychiatric consequences when combined with intense, prolonged combat stress.
Lead author Jeffrey J. Bazarian, M.D., M.P.H., associate professor of Emergency Medicine at the University of Rochester Medical Center and a member of the 2007 Institute of Medicine committee on veterans’ brain injuries, commented that while chronic stress from combat clearly contributes to PTSD, physical forces such as blast exposure may also play a role in the syndrome’s development. The study highlights that some brain injuries remain hidden to routine clinical evaluation yet may be important contributors to long-term mental health outcomes.
Detecting these subtle injuries currently depends on advanced neuroimaging such as DTI, which can be costly and is not universally available. The authors emphasize the need to develop simpler, practical diagnostic tools that reliably indicate brain injury in large populations of service members, so clinicians can better identify those at higher risk for PTSD and tailor treatment plans accordingly.
About this PTSD research article
The study was funded by the U.S. Department of Veterans Affairs. Co-authors included Kerry Donnelly, Ph.D., VA Western New York Healthcare System; Derick Peterson, Ph.D., Department of Biostatistics and Computational Biology at the University of Rochester Medical Center; Gary Warner, Ph.D., Canandaigua VA Medical Center; and Tong Zhu, Ph.D., and Jianhui Zhong, Ph.D., Department of Radiology at the University of Rochester Medical Center.
Source: University of Rochester Medical Center press release. Image credit: adapted from Flickr user Truthout.org. Original research discussed in context: Journal of Head Trauma Rehabilitation (May/June 2012, Volume 27, Issue 3), with article titled “Diffusion Tensor Imaging Findings Are Not Strongly Associated With Postconcussional Disorder 2 Months Following Mild Traumatic Brain Injury.”