Condition Basics

What is periodic limb movement disorder (PLMD)?

Periodic limb movement disorder (PLMD) is a condition in which a person's legs, and sometimes arms, move repetitively and uncontrollably while he or she is asleep. These episodes of limb movement can disrupt the person's sleep, causing insomnia or daytime sleepiness. Periodic limb movement symptoms are only thought to be a disorder (PLMD) when insomnia or daytime sleepiness cannot be explained by any other problem, such as restless legs syndrome. Recently, it has been found that these movements are often linked to subtle breathing problems.

What causes it?

The exact cause of periodic limb movement disorder (PLMD) is unknown.

PLMD shares many underlying factors with restless legs syndrome, such as a hereditary link, iron deficiency anemia, nerve problems, poor blood circulation in the legs, kidney disorders, and others. But in general the two conditions are seen as being related rather than as causing one another.

What are the symptoms?

People who have periodic limb movement disorder (PLMD) have trouble falling or staying asleep (insomnia), or they feel sleepy during the day because the movements disrupt their sleep. These movements usually are in the legs and occur in some type of pattern. Although a person often is not fully awakened by these movements, they interfere with normal sleep cycles. A bed partner's sleep may also be disrupted.

How is it diagnosed?

Periodic limb movement disorder (PLMD) is diagnosed with a medical history, often including a sleep history from a bed partner, and a physical exam. A sleep study is usually required to detect the movements. A sleep study also can identify other conditions that may be causing symptoms, such as sleep apnea or other subtle breathing problems that may be causing movements.

Many questions remain about the nature of periodic leg movements and PLMD. Some researchers consider the movements to be normal. At least a few movements may occur during sleep in people who do not have restless legs syndrome, especially in the elderly.

How is periodic limb movement disorder (PLMD) treated?

Managing symptoms of periodic limb movement disorder (PLMD) may include:

• Home treatment, such as relaxation exercises or massage.
• Medicines such as dopamine agonists.
• Regular exercise. Try to do moderate activity that adds up to at least 2½ hours a week.