Examining the effects of alcohol use on verbal memory processes in older adults with mild cognitive impairment

Background Excessive alcohol use is associated with memory impairment due to its effects on encoding and retrieval of information. However, the underlying mechanisms in those with neurodegenerative disorders is not well understood. Objective We evaluated the effects of alcohol on verbal memory processes in those with mild cognitive impairment (MCI). Methods Data came from two cohorts, the Comprehensive Assessment of Neurodegeneration and Dementia and the Ontario Neurodegenerative Disease Research Initiative. Participants were diagnosed with MCI due to Alzheimer's disease or cerebrovascular disease, and categorized into “zero”, “low-medium”, or “high” alcohol use groups. We compared occurrence of any intrusion, total intrusions, change in intrusions post-interference, and intrusion subtypes on the Rey Auditory Verbal Learning Test across groups. Results We analyzed 521 participants with high (n = 79), low-medium (n = 304), and zero (n = 138) alcohol use. Mean (SD) age was 71.6 (7.4) years and did not differ between groups. The high alcohol use group had higher occurrence of any intrusions (96.2%) compared to the low-medium (87.2%), and zero (92.8%) alcohol use groups (p = 0.027). Alcohol use was associated with increased post-interference intrusions, with the high group adjusted mean (M), standard error (SE) = 1.7 (0.3), low-medium group M(SE) = 1.0 (0.2), and zero group M(SE) = 0.9 (0.2), (p = 0.027). Other intrusion subtypes did not differ between groups. Conclusions Individuals with MCI and excessive alcohol use are more susceptible to interference from recently learned task-irrelevant information. Findings may inform future research regarding mechanisms of alcohol related memory impairment.