A - 133 Self-Reported Loss of Consciousness Predicts Executive Functions in Veterans with a History of Traumatic Brain Injury

The long-term cognitive effects of traumatic brain injury (TBI) in military personnel remain unclear and need to be better understood. We assessed how cognitive performance was related to the remote history of TBI involving loss of consciousness (LOC) and blast injury (regardless of LOC) in veterans.Veterans (N = 101; age 42.8 ± 10.5 years; 10 Females) with a self-reported history of TBI and persistent cognitive symptoms were recruited. Effects of (1) the presence of LOC, (2) total number of TBIs with LOC (0, 1-2, >2), and (3) the presence of blast injury were examined on composite scores from tests of executive function (Trail-Making Test B, Color Word Interference), word retrieval (Boston Naming, Letter and Category Fluency), processing speed (Trail Making-A, Color Word Naming/Reading), and episodic memory (Rey-Auditory Verbal Learning Test-total learning and delayed recall), while controlling for age, sex, years of education, and total number of TBIs.TBI with LOC was a significant predictor of executive function (p = 0.014) and processing speed (p = 0.014), with more episodes of LOC predicting lower functioning, but not of word retrieval or episodic memory (p > 0.1). Additionally, presence of a blast injury, regardless of LOC, did not predict differences in function on any of the composite measures.Self-reported TBI history with LOC was associated with poorer executive function and processing speed. The findings further characterize the relationship between TBI history and long-term cognitive sequelae in veterans, particularly suggesting LOC can affect neural systems underlying executive function and processing speed.