About Sleep Disorders

Restless Legs Syndrome and Periodic Limb Movement Disorder

Restless Legs Syndrome (RLS)

A self-descriptive term, this disorder appears in otherwise healthy people. It is not related to emotional or psychiatric disorders. Although it affects primarily the legs, it can also affect the arms. People experience restless legs in many different ways, but all describe very unpleasant "creepy, crawly" sensations that occur in the legs when they are sitting or lying still, especially at bedtime. Characteristically, the sensation is eased by moving the legs, such as getting up to walk.

For some people, RLS is very painful, but the pain is not like that of a leg cramp. If you suffer from RLS, you will find that it occurs primarily when you are awake, but it can also affect your ability to fall sleep. The constant need to stretch or move the legs to get rid of the uncomfortable or painful feelings often prevents a person with RLS from falling asleep. Extreme tiredness during the day can be one result, with the inability to participate in normal activities or carry out regular duties.

Periodic Limb Movement Disorder

Another disorder that affects the limbs, and affects a person’s ability to sleep at night and function normally during the day, is Periodic Limb Movement Disorder (PLMD). While the leg movements of RLS are a voluntary response to ease the uncomfortable feelings in the limbs when a person is awake, the movements of PLMD occur most often when a person is asleep and are involuntary. People with PLMD are often not aware of these movements, although they may occasionally notice the involuntary movements of PLMD while they are awake. Bed partners can notice the leg movements, often by a slight jerking of the mattress or bed. Most people with RLS have PLMD, but patients with PLMD often do not have RLS.

How common are RLS and PLMD?

Five to 10 percent of the population experience the discomfort or pain of RLS at some time in their lives. Severe cases of RLS, although not common, can be hereditary. The disorder is more common in older individuals but can occur at any age in both men and women.

PLMD is rare in people under 30 years of age, but becomes more common as people grow older. PLMD affects 5 percent of people age 30-50; 25 percent of people age 50-65; and 44 percent of people over age 65. Men and women are equally likely to be affected.

What causes these disorders?

Approximately 30 percent of RLS cases have a hereditary cause. For the other 70 percent, the causes are not yet clearly known, however some situations seem to have a connection with the symptoms of RLS. These can include poor blood circulation in the legs, nerve problems, muscle disorders, kidney disease, alcoholism and vitamin or mineral deficiencies. The cause of PLMD is also unclear. The same factors that are associated with RLS are associated with PLMD.

Find out about RLS and PLMD Treatments offered at Hoag Sleep Disorders Center.

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