BRAIN Health Project 1: Effects of Repetitive Mild Traumatic Brain Injury BRAIN Health

Nearly 378,000 mild traumatic brain injuries (mTBIs) have occurred among U.S. military personnel since 2000, making this a signature wound of post-9/11 conflicts. These injuries can cause a myriad of symptoms (e.g., dizziness, headache, fogginess) and impairments (e.g., cognitive, ocular, vestibular).

In most cases, these issues resolve within a month, but for many, they remain for months or years and become chronic. A complicating factor for many military personnel is that occupations hazards from combat and training put them at high risk for repetitive mTBI (rmTBI).

These repeated injuries can lead to persistent effects including chronic migraine, cognitive impairment, dizziness, psychological health problems, and sleep problems that can result in long-term morbidity, reduced operational readiness, and adverse effects for service members, veterans, and their families.

Research gaps in the field

Currently, there is a gap in the understanding of the long-term consequences of rmTBI and whether or not there is a dose-response for these effects. Some research shows that multiple mTBIs are linked to long-term behavioral, cognitive, neuromotor, and psychological health consequences, while contrary evidence suggests that may not be true, especially if the mTBIs are assessed and managed in a timely fashion. Still other evidence indicates the greatest risk for long-term effects comes after three or more mTBIs.

Neither is there a clear set of predictors, be they clinical assessments or biological markers, that can be used to identify service members who are most at risk of long-term consequences. Good scientific data is needed in all of these areas to help guide patient care and mitigate the rmTBI’s effects on military service members and civilians.

Looking for answers

This STRONG STAR-affiliated project is one of a group of separate but related studies led by Anthony Kontos, PhD, of the University of Pittsburgh called “Brain Risk Assessment for Individual Neurological (BRAIN) Health: Understanding/Preventing Consequences From Repetitive mTBI and Head Impact Exposures,” which seeks to inform the field on the unique contribution of different levels of mTBI exposure along with biological risk factors on BRAIN health outcomes.

For this aim, investigators will conduct a retrospective study with 150 military service members from Fort Hood, Texas, and 150 civilians recruited through the University of Pittsburg. Those individuals will be divided into three groups: (1) 100 participants who have had three or more rmTBIs, (2) 100 who have had one or two rmTBIs, and (3) 100 with no history of mTBI.

With each group, they will evaluate a unique and clinically feasible combination of evidenced-based individual risk factors and multidomain clinical markers (e.g., cognitive, behavioral, and neuromotor) as well as blood-based biomarkers.

Expected outcomes

At the end of the project, investigators expect to have characterized BRAIN health-related outcomes including chronic migraines, dizziness, neurocognitive symptoms, posttraumatic headaches, psychological health, and sleep-related problems, as well as mild cognitive impairment and traumatic encephalopathy syndrome associated with different levels of rmTBI exposure in service members and military-aged civilians.

They expect project findings to support the overall multi-study effort to characterize the dose-specific effects of rmTBI and identify those at risk for these effects by providing the following:

1. empirical evidence to better characterize dose-specific effects of chronic exposure to rmTBI
2. evidence of potential early mild cognitive impairment in service members with high rmTBI exposure
3. data to inform the development of targeted strategies to mitigate the domain-specific effects of rmTBI in civilians and service members
4. empirical evidence to inform exposure-based guidelines for rmTBI for military service members,
5. characterization of blood-based biomarker signatures associated with dose-specific exposure to rmTBI,
6. direct comparison of differences in rmTBI-related outcomes between service members and civilians.

Overall, the findings from the proposed project will inform strategies to mitigate the short and long-term effects of rmTBI on military service member’s BRAIN health.