B - 66 Cognitive Dispersion Is Uniquely Associated with Executive Functions in HIV Disease

Abstract Objective Among persons living with HIV (PLWH), higher levels of intraindividual variability (IIV) across a battery of neuropsychological measures (i.e., dispersion) increase the risk of dependence in everyday functioning. Higher levels of dispersion are theorized to reflect lapses in executive aspects of attention, but few studies have directly evaluated the construct validity of dispersion. Method 72 PLWH completed the Cogstate battery (www.cogstate.com). Exclusion criteria were inability to provide informed consent, psychosis, active substance use disorders, and major neurological conditions. Dispersion was operationalized as a coefficient of variance (CoV) across age-adjusted scores on six tests from the Cogstate battery (i.e., intra-individual standard deviation divided by the intra-individual mean). The predictor variables were mean-level, demographically-adjusted performance scores from well-validated clinical measures of executive functions (Trailmaking Test B, WCST-64 Perseverative Responses, PASAT-50, and Verbal Fluency), psychomotor speed (WAIS-III Digit Symbol, Trailmaking Test A, Grooved Pegboard), and episodic memory (HVLT-R and BVMT-R Learning and Delayed Recall). Results A multiple regression analysis indicated that the three domain-level cognitive predictors explained 12.1% of the variance in Cogstate CoV (p = 0.03). Within this model, lower levels of executive functions were significantly associated with higher CoV on the Cogstate (p = 0.01), but the psychomotor and memory domains were not (ps > 0.05). Conclusion The findings from this cross-sectional study align with cognitive theory in demonstrating dispersion is uniquely associated with external measures of executive functions (e.g., cognitive flexibility) among PLWH. Future experimental studies are needed to determine the precise executive mechanism of dispersion.