Impact of highly active antiretroviral therapy on cognitive processing in HIV infection: cross-sectional and longitudinal studies of event-related potentials

Patients with HIV infection often complain of cognitive disturbances, which can be related to AIDS dementia or HIV-associated encephalopathy (HIVE). We investigated the impact of highly active antiretroviral therapy (HAART) in comparison with other therapeutic regimens on the progression of these cognitive disturbances as measured by visual event-related potentials (ERP). In a cross-sectional study, 214 patients without secondary neuromanifestation of their infection were divided into four groups with respect to their treatment status for 1 year before examination: (1) without antiretroviral treatment, (2) zidovudine monotherapy, (3) zidovudine in combination with didanosine, zalcitabine, or lamivudine, and (4) HAART. In a prospective longitudinal study, we divided 54 patients into three groups: (1) without antiretroviral treatment, (2) zidovudine monotherapy, and (3) HAART. Latencies of the P2, N2, and P3 components and the amplitude of the P3 component were evaluated. A significant negative correlation between CD4(+) lymphocyte cell count and P3 latency was found in all patients (p < 0.004). In the cross-sectional study, P3 latency was significantly decreased in the HAART group as compared with patients with no antiretroviral treatment (p < 0.01). During the 1-year period of the prospective longitudinal study, the P3 latency significantly increased in patients with no antiretroviral treatment (p < 0.05) and significantly decreased in patients with HAART (p < 0.05). In summary, these results suggest that HAART has an improving therapeutic effect on cognitive processing in HIV-infected patients and is superior to zidovudine monotherapy or dual antiretroviral treatment. Because prolongation of ERP might in part reflect HIVE, we conclude that this condition represents an indication for HAART.