Sleep duration and mental well-being are associated with delayed memory in a 12-week digital and remote community-sample study

Unsupervised digital memory assessments are increasingly used in the field of Alzheimers disease to detect cognitive changes, recruit for clinical trials, and monitor cognitive changes longitudinally. However, the impact of factors like sleep and mental well-being on delayed memory task performance remains unclear. Adults aged 18 and older from a community sample across Germany (19-85 years) completed weekly a delayed memory recall task (Object-in-Room Recall, ORR) via the neotivTrials platform over 12 weeks. They also completed brief surveys on wake- and bedtime, and mental well-being (score created from happiness, calmness, energy, freshness, and interest items). Multilevel linear mixed models examined within- and between-person effects of sleep duration the night before testing (n = 329) and mental well-being over the preceding eight days (n = 234) on delayed associative memory. A quadratic term for sleep was included to test a hypothesized U-shape relationship, and interactions with age, gender, and subjective memory decline were analyzed. Sleeping more than ones usual average the night before testing was associated with better delayed memory ({beta} = 0.03, p = 0.02), while no between-person sleep effects emerged. Better delayed memory performance was also linked to better mental well-being, both relative to ones own average ({beta} = 0.05, p = 0.01) and the sample average ({beta} = 0.12, p = 0.01). These effects were consistent across age, gender, and subjective memory decline, except for a stronger well-being-performance association at older ages. No quadratic effects of within- or between-person sleep duration on delayed memory were found. These findings suggest that participants averages of sleep duration and mental well-being should be considered when interpreting performance on remote digital memory assessments. Additionally, by enabling frequent assessments, remote testing designs allow the examination of within-person associations between predictors and cognition, unlike cross-sectional assessments, which rely on potentially noisy one-time estimates.