Medical Disorders

Abstract

Sleep-related movement disorders represent a newly established category of sleep disorders in the new International Classification of Sleep Disorders, second edition (ICSD-2), recently published (2005). This category includes restless legs syndrome (RLS), periodic limb movement disorder (PLMD), sleep-related leg cramps, sleep-related bruxism, sleep-related rhythmic movement disorders (RMDs), sleep-related movement disorder due to a drug or substance, and sleep-related movement disorder due to a medical condition; finally sleeprelated movement disorder, unspecified when the disturbance does not fit into any of the above disorders. Some of these entities were previously categorized within the parasomnias or the wake-sleep transition disorders. Mostly, they involve simple, stereotyped movements during sleep or at the transition between waking and sleeping. RLS is a more complex disease with sensory disturbances occurring at rest and in the evening, and in which the motor accompaniment is mainly represented by the periodic limb movements in sleep (PLMS). All of these sleep-related movement disorders may cause fragmented sleep, insomnia, and/or excessive daytime sleepiness (EDS).