HIV infection can produce a range of cognitive and behavioural symptoms that become more frequent and severe as the immune system deteriorates. This case-control study assessed the reaction time and the motor speed of Nigerian Africans with HIV or AIDS using the simple reaction time and finger-tapping tasks, and correlated their performances with their CD4 levels. A total of 288 age-, sex-, and level of education-matched subjects, comprising 96 HIV-positive patients with symptomatic illness, 96 HIV-positive patients with asymptomatic infection, and 96 HIVnegative controls, participated in the study. The mean CD4 cell counts of the controls, HIV-positive asymptomatic subjects, and HIV-positive symptomatic subjects were 682 ±44, 284 ±62 and 142 ±36, respectively (p < 0.05). There was no significant difference in the reaction time and motor speeds of the asymptomatic HIV-positive subjects and the controls (p > 0.05), but there was significant prolongation of reaction time and reduced finger taps among the symptomatic HIV-positive subjects (p < 0.01). The cognitive performance was worse in subjects with CD4 cell counts less than 200/µl as compared with subjects with CD4 cell counts greater than 200/µl. We conclude that there is no significant prolongation of reaction time and reduced motor speed in asymptomatic HIV-positive individuals but there is a definite cognitive deterioration with progressive reduction in CD4 levels.
Keywords: CD4 level, cognition, finger-tap task, neurophysiology, reaction time
African Journal of AIDS Research 2006, 5(3): 217–220