Actigraphy is a method used in sleep research and clinical sleep medicine to assess an individual's sleep-wake patterns and circadian rhythms. It involves the use of a small, wrist-worn device called an actigraph to continuously monitor and record movement and activity levels. The data collected from actigraphy can provide valuable insights into a person's sleep quality, duration, and consistency, as well as identify potential sleep disorders such as insomnia, sleep apnea, and circadian rhythm disorders. Actigraphy is a non-invasive and cost-effective alternative to traditional sleep monitoring methods such as polysomnography, making it a popular tool in both research and clinical settings.