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INTRODUCTION: Degradation of fractal patterns in actigraphy independently predicts dementia risk. Such observations motivated the study to understand the role of fractal regulation in the context of neuropathologies.METHODS: We examined associations of fractal regulation with neuropathologies and longitudinal cognitive changes in 533 older participants who were followed annually with actigraphy and cognitive assessments until death with brain autopsy performed. Two measures for fractal patterns were extracted from actigraphy, namely, α (representing the fractal regulation at time scales of <90 min) and α (for time scales 2 to 10 h).RESULTS: We found that larger α was associated with lower burdens of Lewy body disease or cerebrovascular disease pathologies; both α and α were associated with cognitive decline. They explained an additional significant portion of the variance in the rate of cognitive decline above and beyond neuropathologies.DISCUSSION: Fractal patterns may be used as a biomarker for cognitive resilience against dementia-related neuropathologies.