Sleep is characterized, from a behavioral point of view, by a physical quiescence. However, sleep can be disrupted by movements which can occur before falling asleep, during the sleep-wake transition, or during sleep. Some of these movements may be considered quasi-physiological because they are very common in the general population and have little or no clinical impact. However, others may have an impact on sleep quality, or be associated with other neurological conditions. Patients' symptoms and complaints, the movements' description by witnesses, home video and video-polysomnographic recordings in the sleep laboratory allow to establish the diagnosis. The instauration of a treatment should be guided by clinical repercussions.