HIV and the brain: evidence of early involvement and progressive damage

AIDS is often accompanied by progressive encephalopathy and 'subcortical' dementia, but there is uncertainty regarding how early the brain involvement may begin in the course of HIV infection. This study used a cognitive auditory 'oddball' paradigm to elicit sensory and cognitive event related potential (ERP) components from healthy controls and from patients at different stages of HIV infection. Sensory component latencies did not differ between groups, but cognitive components showed progressive delays corresponding to increasingly severe clinical stages of HIV infection. The earliest changes were found among asymptomatic HIV + patients, suggesting that this test is a sensitive indicator of early subclinical CNS damage. In contrast, neither frequency analysis nor nonlinear dynamical analysis of the EEG showed differences between healthy controls and patients.