PSEN1 and Alzheimer disease: Extensive research suggests a bidirectional link between sleep disturbances and AD.2–4 Alterations in sleep architecture can precede cognitive decline by decades and are prominent in more than half of all patients.4 Furthermore, similar sleep-wake disruptions were reported in an APP/PS1 mouse model upon development of Aβ plaques.2 The analysis presented here provides evidence showing that the sleep-wake cycle is already to a minor extent perturbed in young APP/PS1 mice, along with a shift toward longer wakefulness (Figure 1).