A - 139 Neurobehavioral Symptoms Are Not Associated with Objective Neuropsychological Test Performance in a Group of Veterans and First Responders Seeking Care for Post-Concussive Symptoms.

OBJECTIVE: Subjective post-concussive neurobehavioral symptoms do not often relate to objective cognitive assessment. This archival analysis aimed to characterize the relationship of subjective neurobehavioral symptoms to neuropsychological tests among military veterans and retired first responders with previous mild TBI (mTBI) presenting to an outpatient multidisciplinary program.

METHODS: 51 patients (88% male; 82% White; 94% veteran), ages 25-68 (M = 43.9, SD = 10.1) underwent neuropsychological evaluation with a flexible battery (M subtests = 29.6; SD = 5.2), through the Transforming Health and Resilience in Veterans (THRIVE) Program at UNC-Chapel Hill. The proportion of below average neuropsychological scores (i.e., ≤ 8th percentile on published norms) was modeled as a function of three subscales (Affective, Cognitive, Somatosensory) on the Neurobehavioral Symptom Inventory (NSI) and estimated premorbid IQ (PIQ) using fractional logit regression with quasi-maximum likelihood estimation and heteroskedasticity consistent "HC1" standard errors. Model diagnostics and sensitivity analyses for overly influential cases (|DFBETAS| ≥ 2/√n) were conducted.

RESULTS: Thirty-eight individuals were included in analyses after removing those with invalid test performance (n = 4) and missing data (n = 9). The mean (median) observed below average scores was 10.9% (5.7%), with the predicted proportion at 8%. No NSI subscale was related to neuropsychological performance. However, upon removal of two overly influential cases, PIQ was inversely associated with rate of low scores - OR: 0.61 (95% CI: 0.36-0.97), SE: 0.14, p = 0.035.

CONCLUSION: Subjective neurobehavioral symptoms were unrelated to objective neuropsychological tests in veterans and first responders seeking care for TBI-related symptoms.