MAPT and early-onset autosomal dominant Alzheimer disease: CSF biomarkers, including amyloid-β 42 (Aβ42), total tau (t-tau) and phosphorylated tau (p-tau), reflect key aspects of Alzheimer’s disease pathophysiology, correlating well with amyloid PET,19 and have been validated in providing early high diagnostic accuracy.20,21 Sleep-wake activity has been shown to affect their production, release, clearance (via the glymphatic system) and metabolism.22,23 However, the precise nature of sleep abnormalities and even the direction of its correlation with Alzheimer’s disease CSF biomarkers has not been consistently reported in the literature.