Background. Previous research has suggested that several factors may influence the presence of
cognitive impairment in human immunodeficiency virus (HIV) infection. The objective of this study
was to assess the impact of cognitive reserve capacity and other variables on neuropsychological
performance in early HIV infection.
Methods. The neuropsychological performance of 100 HIV-seropositive subjects without AIDS (71
men and 29 women) was compared with that of 63 seronegative controls (51 men and 12 women).
Measures included a neuropsychological battery, a medical examination and a psychiatric
assessment. Cognitive reserve scores were based on a combination of years in school, a measure of
educational achievement, and an estimate of pre-morbid intelligence.
Results. HIV-positive subjects had longer reaction time latencies than HIV-negative subjects. Those
in the HIV-positive group with low cerebral reserve scores showed the poorest performance on the
neuropsychological tests. The prevalence of cognitive impairment was significantly higher in the
HIV-positive group (27%) than in the controls (3·2%). Multiple regression analysis and logistic
regression analysis were used to identify factors associated with global neuropsychological
performance and cognitive impairment. Older age, lower cerebral reserve scores and not being on
zidovudine treatment were associated with lower global neuropsychological scores and with the
presence of cognitive impairment.
Conclusions. Our results suggest that although cognitive impairment is not characteristic of early
HIV infection, there is a subgroup of subjects who perform more poorly than expected. A lower
reserve capacity, older age and not being on zidovudine treatment are factors that lower the
threshold for neuropsychological abnormalities in cases of early HIV infection.