Context Matters: Influence of Injury Context on Long-Term Psychiatric and Cognitive Outcomes in Combat Veterans With Mild Traumatic Brain Injury History.

OBJECTIVE

To examine the relationship between injury context with psychiatric and cognitive outcomes among combat-exposed Veterans and Service Members with remote mild traumatic brain injury (mTBI).

SETTING

Veterans and Service Members enrolled in the Long-Term Impact of Military-Relevant Injury Consortium (LIMBIC)-Chronic Effects of Neurotrauma Consortium (CENC).

PARTICIPANTS

LIMBIC-CENC-enrolled participants who had sustained an mTBI exclusively in combat zones (c-mTBI +; n = 314), mTBI sustained exclusively in non-combat settings (c-mTBI-; n = 526), or no history of mTBI (no TBI; n = 347). Inclusion criteria for this study included (1) availability of all mTBI injury-related characteristics, (2) completion of all psychiatric symptom measures, and (3) completion of all neuropsychological measures used for this study.

DESIGN

Cross-sectional secondary analysis.

MAIN MEASURES: Primary outcomes of interest included total scores on self-reported psychiatric symptom measures (post-traumatic stress, neurobehavioral, and cognitive concerns) and objective cognitive composite test scores (attention, learning, processing speed, executive function, and delayed recall). All analyses adjusted for age, gender, and education.

RESULTS

Results of separate multivariate analyses of variance indicated that the c-mTBI+ group reported higher post-traumatic ( ηP2  =  .08) and neurobehavioral symptoms ( ηP2  =  .07), and cognitive concerns ( ηP2  =  .04) compared to the c-mTBI- and no TBI groups, whereas the c-mTBI- and no TBI groups did not differ except on cognitive concerns. Additionally, groups did not differ across cognitive composite performance except for significant though weak group differences on learning ( ηP2  =  .01), delayed recall ( ηP2  =  .03), and processing speed ( ηP2  =  .01). Separate hierarchical regression analyses indicated psychiatric symptom burden explained 7-18% of the total variance in cognitive composite performance as a function of mTBI group history ( p s ≤ .002).

CONCLUSIONS

These findings build upon prior work showing that injury context - the context in which mTBI occurs - may play an important role in long-term psychiatric and cognitive outcomes.