Event-related potential index of semantic mnemonic dysfunction in abstinent alcoholics

Background: The objective of the study was to expand the investigation of the match/mismatch mnemonic impairment in the semantic domain in sober alcoholics. Methods: Event-related potentials (ERPs) were recorded from 28 healthy adults and 36 sober alcoholics in a category (either animals or fruits/vegetables) match/nonmatch S1–S2 paradigm. Results: There was a significant interaction of ERP amplitude (c3) between groups (controls vs. alcoholics) and stimulus conditions (category match vs. nonmatch) at the posterior brain regions; the c3 component was smaller for the category match than for nonmatch trials in controls, with the absence of such c3 differences in alcoholics. There were no significant ERP differences between the two groups in processing the sample stimuli. The ERPs (c2) elicited by the animal category were larger than those for the vegetable category in both groups. The alcoholics showed prominent suppressed activation of left temporo-occipital brain regions under both matching and nonmatching conditions, as demonstrated by the current source density maps. The alcoholics were also slower and less accurate than the controls in judging both category matching and nonmatching stimuli, while neither of the two groups demonstrated shorter response times to the matching stimuli. Conclusions: These data suggest that alcoholics are less efficient in the semantic mnemonic match/nonmatch process, and are less likely to be deteriorated in the stage of forming the template for such match/nonmatch comparisons.