Restless Leg Syndrome & Periodic Limb Movement Disorder

Restless leg syndrome (RLS) is a sensorimotor disorder that creates abnormal sensations and movements of the legs, usually at night. Periodic limb movements (PLMs) are repetitive movements of the legs seen during in-lab sleep tests.


Restless leg syndrome (RLS) is caused by an iron deficiency in the brain, although the cause of the deficiency remains unknown. RLS can begin at any age and is more common in women than men. Certain medications, such as antidepressants, can cause or aggravate restless leg symptoms.

About 80% of individuals with restless leg syndrome have periodic limb movements (PLMs) seen during in-lab sleep studies; however, most individuals with PLMs do not have restless leg syndrome. PLMs can be observed in a variety of sleep disorders as well as in up to 15% of individuals without a sleep disorder.


Characteristically, individuals with RLS describe substantial discomfort late in the evening or just as they get into bed. The discomfort is often described as an urge to move their legs, although movement provides only temporary relief. Symptoms worsen at night and while at rest which can become an obstacle to falling asleep and staying asleep. Individuals with RLS often experience similar symptoms when seated for long periods of time.


There are well established guidelines for treatment of RLS, including use of medications. Iron replacement is especially important when an iron deficiency is present.

Sleep Disorders Center

The Sleep Disorders Center at BIDMC is one of the largest academic sleep centers in New England. This multi-disciplinary center includes neurologists, pulmonologists and psychologists who treat adult patients with the full range of sleep disorders, ranging from sleep apnea to insomnia, narcolepsy to restless leg syndrome.

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