However, given the existing literature connecting NREM physiology and cognitive functioning [75, 76], it is intriguing to hypothesize that the sleep EEG constitutes a sensitive precursor of cognitive alterations that may arise from the progression of disease and/or the detrimental effects of chronic antipsychotics use, analogous to biomarkers such as tau burden tracking early stages of Alzheimer’s disease years before symptoms emerge [77]. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.