Acute Effects of Moderate Alcohol on Psychomotor, Set Shifting, and Working Memory Function in Older and Younger Social Drinkers

Objective: Despite substantial attention being paid to the health benefits of moderate alcohol intake as a lifestyle, the acute effects of alcohol on psychomotor and working memory function in older adults are poorly understood. Method: The effects of low to moderate doses of alcohol on neurobehavioral function were investigated in 39 older (55-70 years; 15 men) and 51 younger (25-35 years; 31 men) social drinkers. Subjects received one of three randomly assigned doses (placebo, .04 g/dl, or .065 g/dl target breath alcohol concentration). After beverage consumption, they completed the Trail Making Test Parts A and B and a working memory task requiring participants to determine whether probe stimuli were novel or had been presented in a preceding set of cue stimuli. Efficiency of working memory task performance was derived from accuracy and reaction time measures. Results: Alcohol was associated with poorer Trail Making Test Part B performance for older subjects. Working memory task results suggested an Age x Dose interaction for performance efficiency, with older but not younger adults demonstrating alcohol-related change. Directionality of change and whether effects on accuracy or reaction time drove the change depended on the novelty of probe stimuli. Conclusions: This study replicates previous research indicating increased susceptibility of older adults to moderate alcohol-induced psychomotor and set-shifting impairment and suggests such susceptibility extends to working memory performance. Further research using additional tasks and assessing other neuropsychological domains is needed.