Cognition and Other Predictors of Functional Disability among Veterans with Mild Traumatic Brain Injury and Posttraumatic Stress Disorder

Background: Limitations in everyday functioning are frequently reported by veterans with a history of mild traumatic brain injury (mTBI) and/or posttraumatic stress disorder (PTSD). Multiple factors are associated with functional disability among veterans, including depression, poor social support, cognition, and substance use. However, the degree to which these factors, particularly cognitive capacities, contribute to functional limitations remains unclear. Methods: We evaluated performance on tests of processing speed, executive functioning, attention, and memory as predictors of functioning on the World Health Organization Disability Assessment Scale (WHODAS) 2.0 in 288 veterans. Participants were placed in one of the following groups: PTSD-only, mTBI-only, mTBI + PTSD, and neither PTSD nor mTBI (deployed control group). Cognitive test performances were evaluated as predictors of WHODAS 2.0 functional ratings in regression models that included demographic variables and a range of mood, behavioral health, and postconcussive symptom ratings. Results: Multiple cognitive test performances predicted WHODAS 2.0 scores in the deployed control group, but they generally did not predict functioning in the clinical groups when accounting for demographics, mood, behavioral health, and postconcussive symptoms. Conclusions: In veterans with mTBI and/or PTSD, cognitive test performances are less associated with everyday functioning than mood and postconcussive symptoms.