Objective: To examine the degree to which P3A latency was sensitive to the early and progressive effects of human immunodeficiency virus (HIV) disease on frontal cortex function by studying HIV-positive subjects who varied in degree of cognitive impairment. Design: Event-related brain potential studies of four groups of subjects: cognitively nonimpaired high-risk HIV-negative subjects, cognitively nonimpaired HIV-positive subjects, cognitively mildly to moderately impaired HIV-positive subjects, and cognitively severely impaired HIV-positive subjects. Setting: Voluntarily participating subjects on an outpatient basis at a medical center facility. Participants: Seventy-one community-residing gay or bisexual HIV-positive male volunteers were compared with 17 HIV-negative male gay or bisexual subjects used as a control sample. The HIV-positive subjects were stratified with regard to severity of cognitive impairment into the following three subsamples: subjects who were cognitively normal (n=35), subjects with mild to moderate cognitive impairment (n=20), and subjects with severe cognitive impairment (n=16), with the samples closely matched in age. The HIV-positive subsamples were closely matched on percentage of CD4 lymphocytes. Subjects were excluded if they reported a history of drug or alcohol abuse, a major mental disorder, a head injury with loss of consciousness, or brain disease other than HIV related. Main Outcome Measure: P3A latency. Results: P3A latency was significantly delayed in HIV-positive subjects compared with HIV-negative control subjects, with a delay of 12 milliseconds in the cognitively normal group (P<.02) and the magnitude of delay increasing with increasing severity of HIV-associated cognitive impairments (P<.001). Delayed P3A was primarily associated with the progression of HIV-associated cognitive impairment, with a secondary and additive association with severity of HIV-associated medical illness. Conclusion: This finding suggests that delayed P3A latency is sensitive to the relatively early central nervous system effects of HIV and progresses with worsening of the central nervous system effects of HIV.
