Sleep disturbances are common in Alzheimer's disease (AD) and AD-related dementia (ADRD). We performed a sleep study on Tg-SwDI mice, a cerebral amyloid angiopathy (CAA) model, and age-matched wild-type (WT) control mice. The results showed that at 12 months of age, the hemizygous Tg-SwDI mice spent significantly more time in non-rapid eye movement (NREM) sleep (44.6 ± 2.4% in Tg-SwDI versus 35.9 ± 2.5% in WT) and had a much shorter average length of wake bout during the dark (active) phase (148.5 ± 8.7 s in the Tg-SwDI versus 203.6 ± 13.0 s in WT). Histological analysis revealed stark decreases of orexin immunoreactive (orexin-IR) neuron number and soma size in these Tg-SwDI mice (cell number: 2187 ± 97.1 in Tg-SwDI versus 3318 ± 137.9 in WT. soma size: 109.1 ± 8.1 μm