Alcohol Use and Trajectory Changes in Mnemonic Discrimination Among Older Adult Non-Problem Drinkers

Older adults exhibit reduced performance on the mnemonic similarity task (MST), demonstrating greater difficulty distinguishing previously encountered items from highly similar lure stimuli. Whether non-problem alcohol consumption exacerbates these recognition memory deficits in older adults remains unclear.

One hundred twenty-eight community-dwelling older adult drinkers (65-80 years) completed a continuous recognition version of the MST. Participants were stratified into lower- and higher-risk drinking groups according to National Institute on Alcohol Abuse and Alcoholism (NIAAA) guidelines. The task consisted of 4 blocks of 124 trials in which participants classified stimuli as "old" or "new." Analyses focused on trials requiring discrimination between original items and similar but not identical lures. A mixed-effects logistic regression model examined the effects of drinking group, lure difficulty, block, and their interactions on trial-level accuracy.

Accuracy increased as lure similarity decreased. No drinking group differences were observed in sensitivity to lure difficulty, indicating comparable performance across lure levels in both groups. A significant lure difficulty × block interaction indicated that improvements across blocks were most pronounced for easier lures. Most notably, however, a significant drinking group × block interaction revealed that performance improved across blocks for both groups, with greater improvement among lower-risk drinkers.

The effects of non-problem alcohol consumption on recognition memory in older adults were heterogeneous. While drinking status was unrelated to sensitivity to lure difficulty, it was associated with differences in performance trajectories across repeated task exposure. These findings highlight the importance of examining multiple recognition memory components when evaluating the cognitive effects of chronic alcohol use in aging.