Periodic limb movement disorder (plmd) and restless legs syndrome (rls)

[Luis Fok]

Periodic limb movement disorder involves repetitive movements of the arms, legs, or both during sleep. Restless legs syndrome involves an irresistible urge to move and usually abnormal sensations in the legs, arms, or both when people sit still or lie down.

In people with periodic limb movement disorders, the legs, arms, or both twitch and jerk, disrupting sleep, but people are usually not aware of the movements.
People with restless legs syndrome have trouble relaxing and sleeping because they feel an irresistible urge to move their legs or arms.
Doctors may diagnose restless legs syndrome based on symptoms, but testing in a sleep laboratory is needed to diagnose periodic limb movement disorder.
There is no cure, but drugs used to treat Parkinson disease and other drugs may help control symptoms.

These sleep disorders are more common during middle and older age.
In the United States, restless legs syndrome may affect 5 to 15% of people, but only about 2 to 3% have significant symptoms. It is particularly common among people older than 50. Most people with restless legs syndrome also have symptoms of periodic limb movement disorder, but most people with periodic limb movement disorder do not have restless legs syndrome.
What causes restless legs syndrome and periodic limb movement disorder is unknown. But one third or more of people with restless legs syndrome have family members with the syndrome. Risk factors include the following:

A sedentary lifestyle
Smoking
Obesity

Periodic limb movement disorder commonly occurs in people with narcolepsy or rapid eye movement (REM) sleep behavior disorder.
Both restless legs syndrome and periodic limb movement disorder are more likely in people who have or do the following:

Stop taking certain drugs (including benzodiazepines such as diazepam )
Take stimulants (such as caffeine or stimulant drugs) or certain antidepressants
Have iron deficiency
Have anemia
Are pregnant
Have a severe chronic kidney or liver disorder
Have diabetes
Have a neurologic disorder, such as multiple sclerosis or Parkinson disease