It assessed whether accelerometer-derived sleep–wake cycle (SWC) patterns are linked to future dementia risk and whether they enhance prediction beyond established clinical and demographic factors. It assessed whether accelerometer-derived sleep–wake cycle (SWC) patterns are linked to future dementia risk and whether they enhance prediction beyond established clinical and demographic factors. Adding sleep–wake cycle measures to existing prediction models improved dementia risk prediction beyond age, lifestyle, and clinical factors. Overall, the findings suggest that disrupted sleep–wake rhythms and altered activity patterns may serve as early indicators of dementia risk. Digital Sleep-Wake Cycle Metrics and Dementia Prediction in Older Adults.