Westwood et al.1 demonstrated that long sleep duration could represent a marker of early neurodegeneration leading to dementia. There is evidence of an interplay between sleep and cognition.2 In particular, sleep disturbances are related to the occurrence of dementia by altering brain processes active during sleep.2 The observation by Westwood et al. adds to the literature on sleep and neurodegeneration.3 However, the absence of polysomnographic recordings leaves an unresolved question: why are neurodegenerative processes promoted by long sleep duration?
