Effect of clinical characteristics on cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury.

Objective: To examine the relationship between clinical characteristics and cognitive performance in service members and veterans with histories of blast-related mild traumatic brain injury (mTBI).

Design: This study consisted of 40 Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) service members and veterans; 20 participants reported blast exposure and alteration of mental status consistent with mTBI and 20 participants denied blast exposure and had no history of traumatic brain injury (TBI), but could have experienced extra-cranial injuries. Measures of simple reaction time, processing speed, visual attention, working memory and mathematical processing were used to assess long-term effects of mTBI. Measures of post-traumatic stress symptom severity, pain intensity, sleep difficulty and subjective appraisal of cognition at time of testing were also obtained. Multivariate analyses were conducted with clinical characteristics and mTBI history as predictors of cognitive performance.

Results: There was no evidence of an effect of mTBI history on cognitive performance in this sample. However, post-traumatic stress symptom severity was significantly related to two measures of cognitive performance.

Conclusions: This study demonstrated the importance of considering the effects of current clinical symptoms (e.g. post-traumatic stress) as possibly having greater influence on current cognitive functioning than the effects of a remote history of mTBI.