Abstract
Objective: To examine the association between employment status and neuropsychological functioning in veterans with a history of remote mild traumatic brain injury (mTBI) using 2 approaches to assess cognitive performance: (a) standard, traditional mean cognitive performance; and (b) across-test intraindividual variability (IIV).
Setting: Outpatient Veterans Affairs (VA) hospital.
Participants: Eligibility criteria included veterans with a history of mTBI who performed adequately on performance validity tests. Participants (N = 75; 37 employed, 38 unemployed) were evaluated, on average, about 5.5 years after their most recent mTBI.
Design: Observational cohort study; all participants completed a clinical interview and a comprehensive neuropsychological assessment.
Main Measures: Primary outcomes of interest included mean cognitive composite test scores and IIV scores on tasks of memory, attention/processing speed, and executive functioning.
Results: Logistic regression models showed that mean cognitive performance was not predictive of employment status; however, IIV indices were ( = 7.88, P = .048) and accounted for 13% of the variance. Greater memory-IIV was significantly associated with being unemployed ([beta] = -.16, SE = .07, P = .020, Exp(B) = 0.85; 95% CI, 0.74-0.98).
Conclusion: These findings build upon prior work showing that IIV, or cognitive dispersion, is associated with important functional outcomes following mTBI, including employment status. Future studies are needed to verify these findings, but the present study suggests that IIV indices offer a clinically meaningful marker of cognitive functioning and should be considered when evaluating functional outcomes following head trauma.