An Actical™ is a watch-like device attached to the wrist that uses an accelerometer to measure movement nearly continuously over several days. The American Academy of Sleep Medicine practice parameters report that actigraphy is a useful tool for detecting sleep in healthy individuals, assessing specific aspects in insomnia and restless legs syndrome, circadian-rhythm disorders, and excessive sleepiness. Concurrent with these recommendations is an increased interest in the use of actigraphy as a tool for objectively measuring fatigue. With improved high-end statistical methods for analyzing this data, actigraphy has the potential to become more important as an objective diagnostic tool for determining fatigue, sleep abnormalities and assessing response to treatment.