Acute effects of alcohol on divided and covert attention in men

Rationale: While several studies identified divided attention to be sensiti ve to alcohol effects, the impact of alcohol on covert visual attention is still not clear, despite the latter's important role in perception. Objecti ves: The study tests the effect of acute moderate doses of alcohol on divid ed and covert attention in right-handed, male volunteers. Methods: The desi gn of the study involved a double-blind trial with an alcohol and a placebo condition; measurements were taken before and after an oral dose of 0.6 g/ kg alcohol versus placebo. In the divided-attention task, simultaneous visu o-spatial and auditory stimulation was applied. In a test of covert attenti on, subjects had to shift their attentional focus according to a central cu e, from one location in the visual field to another. Results: Under the div ided-attention condition, reaction times were significantly prolonged after alcohol ingestion compared to placebo. Covert attention pre-post change wa s also significantly different between the alcohol and placebo groups. Ther e is a reduction of false-cueing disturbance for left-appearing stimuli und er moderate alcohol but an increase of disturbance for rightward stimuli, i .e. we found a lateralised pattern of reaction for spatial orienting. In th e placebo group, no significant differences in right-left performance were obtained. Conclusion: The results suggest that sensory-attentional mechanis ms play a key role in altered visual perceptual performance after alcohol i ngestion. Furthermore, differences between the right and left visual field in the cued target-detection task indicate that alcohol exerts an influence on right-hemispheric attentional priming.