Event-related brain potentials in intoxicated and detoxified alcoholics during visuospatial learning.

Event-related potentials and visuospatial learning performance were examined to understand the effects of chronic alcohol use on complex information processing. A total of 18 alcoholic male in-patients in an alcohol treatment program served as participants. Nine persons were seen at time of admission to the program while intoxicated (mean BAC = 18.0 mg/dl). The second group of nine persons was seen detoxified after 4 weeks in the treatment program. Learning consisted of a paired-associate paradigm requiring participants to learn the distinct spatial positions of six, randomly presented "nonsense" shapes. The visuospatial learning performance of the intoxicated alcoholics was superior to that of the detoxified alcoholics. Evaluation of event-related potentials during the visuospatial learning task indicated that while both groups displayed greater right hemisphere amplitudes of P3, P2, N1, and N2-P3 components, the amplitudes of the latter three components were significantly greater in the intoxicated alcoholics. The overall results suggest that compared to the intoxicated alcoholic, the detoxified alcoholic may suffer a disruption in attentional mechanisms related to visuospatial information processing, providing support for a theory that alcohol ingestion serves to balance information processing in the chronic alcoholic.