Movement During Sleep
Restless legs syndrome (RLS) is a neurological disorder characterized by throbbing, pulling, creeping, or other unpleasant sensations in the legs and an uncontrollable, and sometimes overwhelming, urge to move them. Symptoms occur primarily at night when a person is relaxing or at rest and can increase in severity during the night. Moving the legs relieves the discomfort. The sensations range in severity from uncomfortable to irritating to painful.
The most distinctive or unusual aspect of the condition is that lying down and trying to relax activates the symptoms. Most people with RLS have difficulty falling asleep and staying asleep. Left untreated, the condition causes exhaustion and daytime fatigue. Many people with RLS report that their job, personal relations, and activities of daily living are strongly affected as a result of their sleep deprivation. They are often unable to concentrate, have impaired memory, or fail to accomplish daily tasks. It also can make traveling difficult and can cause depression.
As many as 10 percent of the U.S. population may have RLS. Childhood RLS is estimated to affect almost 1 million school-age children, with one-third having moderate to severe symptoms. RLS occurs in both men and women, although the incidence is about twice as high in women. It may begin at any age. Many individuals who are severely affected are middle-aged or older, and the symptoms typically become more frequent and last longer with age.
More than 80 percent of people with RLS also experience a more common condition known as periodic limb movement of sleep (PLMS). PLMS is characterized by involuntary leg twitching or jerking movements during sleep that typically occur every 15 to 40 seconds, sometimes throughout the night. The symptoms cause repeated awakening and severely disrupted sleep. Although many individuals with RLS also develop PLMS, most people with PLMS do not experience RLS. People who have PLMS and do not have RLS or another cause for the PLMS may be diagnosed with periodic limb movement disorder (PLMD). PLMD may be a variant of RLS and thus respond to similar treatments.