AUDITORY P300 ABNORMALITIES AND LEUKOCYTE ACTIVATION IN HIV-INFECTION

To evaluate whether P300 testing might serve as a screening modality f or the early detection of HIV-related neuropathology, we tested 26 HIV infected men (23 without neurologic symptoms, 2 with peripheral neuro pathy, 1 with AIDS-associated dementia) and 15 controls. Although they had no overt neurologic symptoms,the P300 latency was delayed or unde tectable in 30% of patients without clinically evident neurologic dise ase. P300 latencies did not correlate with peripheral blood CD4 T-cell count, serum quinolinic acid or p24 antigen levels, or the numbers of activated peripheral blood monocytes. Three individuals with abnormal P300 latencies had been HIV-seropositive for less than or equal to 1 year, suggesting that delayed evoked responses detect early neurologic dysfunction. P300 responses do not predict imminent dementia. In only one previously asymptomatic individual with abnormal P300 waveforms h ave overt neurologic symptoms developed during a 2-year followup. Exte nded longitudinal studies will be necessary to define the predictive v alue of P300 latencies in the development of AIDS-related dementia. Ho wever, the sensitivity, quantitative nature, and speed of administrati on of this test suggest that it may be useful for identification of ea rly neurologic involvement in HIV infection.