actigraphy
n.β Β«They also filled out sleep questionnaires, kept a log of their hours in bed and participated in six nights of sleep studies with a technique called wrist actigraphy that uses a motion sensorβworn like a watchβto estimate actual sleep duration.Β» ββHeart Disease Associated With Lack of Sleep” by Lynn Shapiro DOTmed.com Dec. 29, 2008. (source: Double-Tongued Dictionary)