Cyclic alternating pattern in sleep electroencephalography as a novel predictor of dementia: A prospective study

INTRODUCTION Cyclic alternating pattern (CAP) is a sleep physiological rhythm observed during non–rapid eye movement (NREM) stage. However, the potential role of CAP for risk of dementia remains unknown. METHODS We studied 2,557 participants enrolled in the prospective Osteoporotic Fractures in Men (MrOS) Sleep Study. CAP features were calculated from electroencephalogram (EEG). The primary outcomes are probable dementia determined by physician diagnosis, Alzheimer's medication use, or a significant cognitive decline. RESULTS Participants in the lowest tertile of A2 index exhibited an increased risk of dementia compared to those in the highest tertile (hazard ratio [HR] = 2.00, 95% confidence interval [CI]: 1.38–2.90). Further, a lower combined A2+A3 index and shorter CAP sequence duration were associated with a higher risk of dementia. The Shapley Additive Explanations method indicates that CAP features were more predictive of dementia risk than conventional sleep parameters. DISCUSSION These findings suggest that specific CAP features may serve as useful predictors to identify those older men at risk of dementia.