Event-related potential evidence of dysfunction in automatic processing in abstinent alcoholics

The preattentive automatic processing of 63 alcoholics and 27 controls was evaluated with an auditory inattentive event-related oddball paradigm. We examined the mismatch negativity and the N2-P3 complex. Results showed significantly greater amplitude for N2, P3 and the N2-P3 complex for controls but no individual lead (Fz, Cz, Pz) differences by group. A group-by-lead interaction was found for N2 and for the N2-P3 complex. There were no significant latency differences between groups; however, a significant age-by-group interaction effect on latency was greatest at the Cz electrode. Results reflect a possible aberration of automatic processing in alcoholics because of a defect in the mnemonic template necessary to match with an infrequent deviant stimuli. We also found suggestive evidence of a relative weakness of frontal cortical organization in alcoholics. Future studies are suggested that would help clarify these differences in alcoholics.