The aim of this study is to quantify the relationship between exposure to traumatic brain injuries (TBI) and persistent post-concussion symptoms (PPCS) in a large group of post-9/11 veterans.
The long-term risks of TBI and repeated non-concussive head impacts have received increasing attention in the last twenty years. At this time, there is still a controversy around the relationship between exposure to TBI and other head impacts as a risk factor for chronic symptoms. Recent case studies have implicated even low-level blast exposure as a potential risk for neurological decline in life and a distinct neuropathology on autopsy, interface astroglial scarring.
Data from post-9/11 service members and veterans (SMVs) who have applied to UCLA Health’s Operation Mend were analyzed for this study. SMVs completed an adapted version of the Ohio State University TBI Identification Method along with screening questions for TBI in military personnel and the Rivermead Post-Concussion Questionnaire (RPQ).
From 705 SMVs (age mean = 39.4 yrs, SD = 8.4 yrs; 88% male) between January 2016 and May 2019, more than 80% report having been near a blast or explosion during deployment. On the RPQ, more than 90% report three or more moderate or severe symptoms, an average of 11 symptoms overall (SD = 4.4) and a score of 44.4 points (SD = 13.0) on a scale of 0 to 64 possible points. We found no significant correlation between the number of different mechanisms of lifetime head or neck injuries and RPQ score.
The number of different mechanisms of injury alone was not a reliable predictor of symptoms in this highly symptomatic population. This illustrates a need for higher resolution brain injury exposure data. The next step will be to investigate whether repeated low-level blast exposure is a unique predictor of neurological outcomes.