A functional linear modeling approach to sleep–wake cycles in dogs

The study of companion (pet) dogs is an area of great translational potential, as they share a risk for many conditions that afflict humans, including those that affect sleep. Although non-invasive polysomnography in dogs has advanced, basic understanding of dog sleep patterns remains poorly characterized. This study established baseline sleep–wake cycle and activity patterns using actigraphy and functional linear modeling (FLM) in healthy, adult companion dogs. Forty-two dogs wore collar-mounted activity monitors for 14 days. FLM demonstrated a bimodal pattern of activity with significant effects of sex, body mass, and age; the effect of age was particularly evident during times of peak activity. FLM can describe normal sleep–wake cycles of healthy adult dogs and the effects of physiologic traits on these activity patterns. This foundation enables characterization of deviations from normal, including those associated with chronic pain and cognitive dysfunction syndrome, improving detection in dogs and enhancing their utility as models for human disease.