Abstract
OBJECTIVE: This study assessed the strength of military-related concussion-, psychological-, and behavioral-related measures to predict neurobehavioral symptom (NBS) reporting in order to help clarify the extent to which persistent NBS reflect lingering effects of concussion vs other psychological/behavioral factors among veterans. METHODS: Baseline analysis included 351 consecutively enrolled veterans in the Translational Research Center for Traumatic Brain Injury and Stress Disorders longitudinal cohort study. One hundred eighty-six returned for a follow-up evaluation averaging 24 months post baseline. The Neurobehavioral Symptom Inventory (NSI) was used to measure NBS reporting. Predictor variables included diagnosis of military-related mild traumatic brain injury (M-mTBI), psychological measures, including posttraumatic stress disorder, mood, anxiety, and substance abuse disorders, and behavioral measures, including self-reported current pain and sleep impairment. Hierarchical and multivariable regression analyses examined the relationships between the predictor variables and NSI scores. The k-fold cross-validation assessed generalizability and validity of the regressions. RESULTS: Baseline analysis revealed that psychological and behavioral conditions independently accounted for 42.5% of variance in the NSI total score compared to 1.5% for M-mTBI after controlling for psychological and behavioral conditions. Prospective analysis revealed that M-mTBI at baseline did not significantly predict NSI score at follow-up, while psychological and behavioral measures at baseline independently accounted for 24.5% of NSI variance. Posttraumatic stress disorder was the most consistent predictor. Cross-validation analyses supported generalizability of the results. CONCLUSIONS: Psychological and behavioral-related measures are strong predictors of persistent NBS reporting in veterans, while M-mTBI is negligible. NBS more likely reflect influential comorbidities as opposed to brain injury, per se.