Which Are the Most Reliable Sleep Parameters that Predict Cognitive Decline and Alzheimer’s Disease?

Sleep disorders can represent an independent risk factor for cognitive decline and Alzheimer’s disease (AD). It remains to be clarified if specific sleep parameters could be considered biomarkers of AD-related neurodegeneration. Several studies solely investigated the results of cross-sectional research, without providing conclusive evidence. Few longitudinal studies showed some inconsistencies in macrostructural and microstructural sleep findings. Methodological heterogeneity among studies can explain the discrepancies in the results. Moreover, the polysomnographic findings are usually related to only one-night recording. The combination of actigraphic recordings with sleep EEG monitoring for some consecutive days should be considered in future research.