For many years, researchers have looked for objective measures to help diagnose traumatic brain injury or post-traumatic stress disorders.

Information from the Defense and Veterans Brain Injury Center’s 15-year natural history study is assisting medical researchers in determining whether a protein found in a patient’s blood could be a promising candidate for future diagnostic tools.

A blow to the head is one of the ways a service members can sustain a TBI, and after witnessing psychologically disturbing events, they may also experience PTSD. Diagnosing these can be complex as they have similar symptoms that can be compounded when both are present.

Since 2000, more than 400,000 active-duty service members have been diagnosed with TBI, according to figures from DVBIC, the Department Department’s center of excellence for traumatic brain injury and a division of the Defense Health Agency Research and Development Directorate. However, a statistic revealing those co-presenting with PTSD has not been compiled.

In a 2018 research review on mild TBI (mTBI) and PTSD, the DVBIC noted that “differential diagnosis will likely continue to be a challenge.”

Jessica Gill, a researcher at the National Institutes of Health, and Dr. Kimbra Kenney, an associate professor of neurology at the Uniformed Services University of the Health Sciences, both located in Bethesda, Maryland, are currently examining patients’ blood to see whether it can help in diagnosing and treating TBI.

“By pairing advances in the laboratory we are now able to detect very small proteins in the blood that provide key insights into pathology that contribute to long-term symptoms in military personnel and veterans with TBIs, as well with PTSDs,” said Gill.

At a recent conference, Kenney explained how specific types of blood proteins were significantly elevated among those with concussions, compared to subjects who had been deployed but not sustained TBIs. Blood samples are being collected at Walter Reed National Military Medical Center as part of their research in a study of the natural history of TBI funded by the DoD and Department of Veterans Affairs.

In another project using data from the 15-year natural history study, researchers are examining blood proteins in subjects who had both sustained a TBI and reported PTSD symptoms. Earlier studies had shown that tau and amyloid-beta-42 proteins indicated the presence of TBI; now researchers believe the presence of both proteins could reveal individuals with both TBI and PTSD.

Study participants consisted of 107 service members. Evidence of TBI was obtained from medical records and interviews at Walter Reed Bethesda. Most participants were diagnosed with a mild traumatic brain injury while the remaining subjects experienced an injury unrelated to TBI but did not lose consciousness. Each participant provided a blood sample and completed a detailed questionnaire. Three groups were formed: those with both TBI and PTSD; those with some other injury and no PTSD; and those with TBI but no PTSD.

The researchers found “tau in plasma is significantly elevated in military personnel who have sustained an mTBI and display concurrent PTSD symptomology.” This finding agrees with earlier civilian studies. Following a TBI, tau elevations are associated with poor recoveries and greater neurological problems.

These studies may show relationships between neurological outcomes and changes at the molecular level. “The novel design of the 15-year study provides the first longitudinal data to untangle complex pathological processes that result in lasting neurological and psychological symptoms and impairments,” Gill said. “By better understanding these processes, we can personalize the care we provide to treat military personnel and veterans to have the biggest impact on their health and well-being.”