Reaction time in patients with HIV/AIDS and correlation with CD4 count: a case-control study.

There are conflicting reports on the presence of neurocognitive dysfunction during the initial, medically asymptomatic stage of HIV infection. This study aimed to assess the psychomotor speed and attention ability of antiretroviral treatment-naïve Nigerian Africans with HIV/AIDS and the impact of CD4 levels on their cognitive performance. Two hundred and eighty-eight randomly selected age-, sex- and level of education-matched subjects participated, comprising 96 HIV-positive asymptomatic and 96 HIV-positive symptomatic patients and 96 HIV-negative controls. The simple reaction and binary choice reaction time tasks were used for cognitive assessment. The binary choice reaction time indicated that the HIV-positive patients had impaired attention ability and significant psychomotor slowing compared with the controls (P<0.05), but psychomotor slowing was obvious among the symptomatic HIV-positive patients only using the simple reaction time tasks. Significant psychomotor retardation was observed in HIV-positive patients with CD4 levels of 200-499 cells/mm(3) (P=0.02) and <200 cells/mm(3) (P<0.001), and impaired ability for sustained attention was present irrespective of the CD4 level (P<0.001). We conclude that psychomotor retardation and impaired attention are significantly worse in HIV-positive subjects compared with controls and are adversely affected by decreasing CD4 levels. The sensitivity of the neuropsychological tool used can affect the degree of impairment measured.