Rosko, Judith.

The P3 and slow wave measures were examined in a simultaneous oddball task in a clinical population of alcoholics and multiple-drug addicted patients. Standard and Deviant tones and lights were used in a counting task in single modality trials in two separate test sessions and tones and lights were used simultaneously but independently in a counting task in which tones were to be ignored and deviant lights were to be counted. Differences between clinical subjects and control subjects and between test sessions were examined. While there were no significant results between test sessions, there were significant differences between controls and clinical subjects in the P3 component. Amplitude of the P3 was smaller for the clinical subjects in all three conditions and in the bimodal task there was evidence in the P3 EP measure that the clinical group had difficulty ignoring the tones, although there were no significant differences in accuracy of count possibly due to a temporal deficiency on the part of the clinical subjects.