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 PLMD?

The exact cause of 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 of PLMD?

People with 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 PLMD diagnosed?

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 PLMD treated?

Managing symptoms of PLMD typically includes:

• Home treatment, such as relaxation exercises or massage.
• Medicines, including dopamine agonists such as ropinirole or pramipexole, benzodiazepines, or the dopamine precursor called levodopa. These medicines, some of which are also used to treat Parkinson's disease, are used only when symptoms are frequent and severe or regularly disrupt sleep.
• Regular exercise. Try to do moderate activity at least 2½ hours a week. It's fine to be active in blocks of 10 minutes or more throughout your day and week.