Influence of cognitive reserve on neuropsychological functioning in asymptomatic human immunodeficiency virus-1 infection

Objective: To evaluate the influence of cognitive reserve or brain reserve capacity on neuropsychological performance in early human immunodeficiency virus (HIV)-1 infection. Design: Cross-sectional group comparison study, based on neuropsychological performance, of HIV-1 seropositive and HIV-1 seronegative participants. Subjects: Seventy-five medically asymptomatic HIV-1-seropositive homosexual or bisexual men and 50 HIV-1-seronegative homosexual or bisexual male controls. Subjects were grouped by HIV-1 status (seropositive vs seronegative) and by cognitive reserve scores (low reserve vs high reserve). Measures: Cognitive reserve scores were based on a combination of years of education, a measure of occupational attainment, and an estimate of premorbid intelligence. Performance on a battery of neuropsychological tests was summarized by empirically derived factor scores and clinical summary ratings. Results: The HIV-1-seropositive subjects with low cognitive reserve scores exhibited significantly greater deficits on measures of attention and information processing speed, verbal learning and memory, executive functioning, and visuospatial performance than did the HIV-1-seropositive subjects with high cognitive reserve scores. In contrast, there were no significant group differences on these measures between both groups of HIV-1-seronegative subjects. Conclusions: Early neuropsychological impairments in HIV-1 infection are most evident in individuals with lower cognitive reserve. As has been found in other neurologic disorders, such as Alzheimer's disease, individuals with greater cognitive reserve may be less sensitive to the initial clinical effects of the underlying neuropathologic process.