Abstract
This study examined the association between cognitive intra-individual variability (IIV), a non-mean-based indicator of underlying neuropathology, and self-reported everyday functioning of 1,086 women with HIV (WWH) and 494 socio-demographically similar women without HIV (WWoH). Objective cognitive performance across seven domains and the self-rated Lawton & Brody scale of Instrumental Activities of Daily Living (IADL) were assessed among participants of the Women's Interagency HIV Study. Two types of cognitive IIV were calculated by taking the standard deviation across seven cognitive domains to calculate dispersion: 1) intra-individual standard deviation (denoted as sdIIV) and 2) coefficient of variation (denoted as covIIV). To account for the longitudinal nature of the data, generalized linear mixed effect models were conducted to examine associations between the dispersion coefficient of cognitive IIV (predictor (sdIIV and covIV)) and functional outcomes (item level scores). Models were conducted in the overall sample (WWH + WWoH), WWH only, virally suppressed (VS)-WWH, and WWoH. sdIIV and covIIV were not associated with any of the IADL items among WWoH but were for WWH and VS-WWH. In WWH covIIV was predictive of poorer functional performance on twice as many IADL items (10 items-money and bills, buying groceries, getting where you need to go, using the phone, home repairs, dressing, laundry, taking/keeping track of medications, taking care of children, work) than sdIIV (5 items). In this study, cognitive IIV predicts functional impairment and different calculations of IIV produce differential predictive value, especially for WWH.