We hypothesized that (1) sleep disturbance and sleep-related autonomic dysfunction would be more evident in APP/PS1 mice than in control mice at the early stage and that these phenomena would also be observed in APP/PS1 at the advanced stage and that (2) the severity of sleep disturbance or autonomic dysfunction would be significantly correlated with the presence of cognitive deficits. The gene discussed is APP; the disease is Cognitive impairment.