[Evoked potentials in neurologically asymptomatic persons during the early stages of HIV infection].

There are few reports on the relevance of evoked potentials in neurologically asymptomatic HIV seropositives. We studied 31 HIV infected males without AIDS or associated clinical neurological abnormalities. Visual evoked potentials by foveal checkerboard stimulation revealed a prolonged VEP latency in 37% of them. HIV seropositives with a pathologic VEP latency showed a significant reduction of their absolute numbers of peripheral blood T-helper cells. This increase of the mean VEP-latency was already significant in HIV seropositives with a T-helper cell count greater than 400/microliters. In 47% of the HIV seropositives the AEP peak I latency was prolonged in combination with a significant decrease of the AEP interpeak latency I-V suggesting endocochlear lesions at peripheral endings of the acoustic nerve or at the basal hair cells. HIV seropositives with a T-helper cell count less than 400/microliters revealed a significant prolongation of the mean AEP interpeak latency III-V indicating a central conduction defect in HIV-seropositives with an immune deficit. Somatosensory evoked potentials after median and tibial nerve stimulation were within the normal range. Since the VEP P100 latencies were significantly longer in HIV seropositives with a normal AEP peak I compared to those with prolonged AEP peak I latencies we postulate that there are different pathophysiological mechanisms underlying.