Does cognitive intra-individual variability predict change in everyday functioning performance in women with and without HIV in the Women's Interagency HIV Study?

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 IIV) and 2) coefficient of variation (denoted as IIV). 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 (IIV and IV)) and functional outcomes (item level scores). Models were conducted in the overall sample (WWH + WWoH), WWH only, virally suppressed (VS)-WWH, and WWoH. IIV and IIV were not associated with any of the IADL items among WWoH but were for WWH and VS-WWH. In WWH IIV 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 IIV (5 items). In this study, cognitive IIV predicts functional impairment and different calculations of IIV produce differential predictive value, especially for WWH.