Sleep-related movement disorders

Sleep-related movement disorders (SRMD) comprise a spectrum of conditions characterized by simple, usually stereotypes movements that occur in sleep or at sleep onset. These disorders result in sleep disruption or daytime sleepiness and fatigue. Many normal sleepers can exhibit sleep related movements, such as hypnic jerks or periodic limb movements; however, to be classified as a SRMD, disturbed sleep or daytime symptoms must be present. The most common SRMD is restless legs syndrome, which consists of complex behaviors to avoid unpleasant sensation; nevertheless, it is classified as a SRMD because of its clear associated with periodic limb movements. SRMD is differentiated from other movements of sleep such as parasomnias by the simple stereotyped behaviors rather than the more complex and often purposeful movements seen in the parasomnias, such as sleep walking. The diagnosis of SRMD often requires both a thorough clinical history and a polysomnogram to characterize the movements and differentiate them from other sleep disorders.