Intra-individual neurocognitive variability confers risk of dependence in activities of daily living among HIV-seropositive individuals without HIV-associated neurocognitive disorders

Abstract

Although HIV-associated neurocognitive disorders (HAND) are the strong predictors of everyday functioning difficulties, approximately half of all functionally impaired individuals are labeled "neurocognitively normal" according to the standard neuropsychological measures, suggesting that novel predictors of functional problems in this prevalent subgroup are needed. The present study hypothesized that increased neurocognitive intra-individual variability as indexed by dispersion would be associated with poor daily functioning among 82 persons with HIV infection who did not meet research criteria for HAND. An intra-individual standard deviation was calculated across the demographically adjusted T-scores of 13 standard neuropsychological tests to represent dispersion, and functional outcomes included self-reported declines in basic and instrumental activities of daily functioning (basic activity of daily living [BADL] and instrumental activity of daily living [IADL], respectively) and medication management. Dispersion was a significant predictor of medication adherence and dependence in both BADL and IADL, even when other known predictors of functional status (i.e., age, affective distress, and indices of disease severity) were included in the models. As a significant and unique predictor of a performance on the range of daily functioning activities, neurocognitive dispersion may be indicative of deficient cognitive control expressed as inefficient regulation of neurocognitive resources in the context of competing functional demands. As such, dispersion may have clinical utility in detecting risk for functional problems among HIV-infected individuals without HAND.