Estimated premorbid intelligence mediates neurobehavioral change in individuals infected with HIV across 12 months

This study tested whether estimated premorbid intelligence moderates worsen ing neurobehavioral dysfunction in HIV infection. 155 homosexual men (54 co ntrols, 49 HIV+ asymptomatic, 24 HIV+ symptomatic, 28 AIDS) with stable dis ease status were tested on measures of executive function at baseline and 1 2-month follow-up. Premorbid intelligence was estimated on the basis of a d emographically-based regression equation (Hamsher, 1984), and participants were classified as average or above-average intelligence. Regardless of dis ease status, participants with above-average IQ showed no declines on measu res of executive function across time. In contrast, among those with averag e IQ, symptomatic groups showed declines, whereas the asymptomatic group di d not. The findings support the hypothesis that estimated premorbid intelli gence mediates declines in neuropsychological function in patients with sta ble HIV status. These findings are consistent with theoretical models of co gnitive reserve capacity.