<unk>  is a non-invasive method of monitoring human rest/activity cycles. A small<unk> unit, also called an actimetry sensor, is worn for a week or more to measure gross motor activity. The unit is usually in a wristwatch-like package worn on the wrist. The movements the<unk> unit undergoes are continually recorded and some units also measure light exposure. The data can be later read to a computer and analysed offline; in some brands of sensors the data are transmitted and analysed in real time.
Actigraphy
Sleep diary
Sleep study
Somnology
Micrographia 
Entropy monitoring
Acceleromyograph
Polysomnography