Early and late cognitive event-related potentials mark stages of HIV-1 infection in the drug-user risk group.

HIV-1 (Human immunodeficiency virus) infection of the brain causes delays in auditory event-related potential (ERP) components. We recorded auditory ERPs from 38 former parenteral drug users (PDUs) at three stages of HIV-1 infection: seronegative; seropositive; stage II; and seropositive, stage IV. There were five response conditions: Go Nogo, Count, Simple Response, Simple Count, and Ignore. P3 peak latencies were significantly delayed and P3 amplitudes were significantly reduced for all seropositives, including asymptomatics, when compared to PDU seronegative controls. In contrast, the P1 and N1 peak latency measures were delayed only for seropositives with acquired immunodeficiency syndrome (AIDS) qualifying illnesses. There was a significant negative correlation between the CD4 count and the latency of P1, N1, and the MMN. Also, increased P1 and N1 amplitudes correlated with indices of disease progression (Choice RT and CD4 counts, respectively). The results extend previous findings by clarifying the pattern of auditory ERP markers of disease progression. Early, as well as late, brain involvement caused by HIV-1 is marked by delays and decreased amplitudes in cognitive components. In addition, late brain involvement is marked by delays and increased amplitudes in specific, automatic, and/or obligatory components.