Restless Leg Syndrome & Periodic Limb Movement Disorder
Restless Leg Syndrome (RLS) and Periodic Limb Movement Disorder (PLMD) are different but related disturbances.

RLS is described as a creep-crawly feeling in the lower legs, thighs and feet causing an irresistible desire to move them, stand and stretch the leg muscles, or to walk about. It is frequently seen in people with uremia, kidney failure, rheumatoid arthritis and during pregnancy. Being overly tired, large amounts of caffeine and exposure to a very warm or cold environment can worsen the symptoms. RLS typically begins at about the age of 30, and frequently gets worse with age. Often RLS is hereditary. People with RLS may complain of insomnia and daytime sleepiness.

Almost all people with RLS also have PLMD, but not all people with PLMD have RLS.

PLMD is a condition associated with leg twitches or kicks that occur when asleep. The kicking/twitching typically lasts from 1/2 to 5 seconds, and occur in a very rhythmic pattern, every 20 to 40 seconds. The person with PLMD usually is not aware of the movements unless the bed partner mentions it. The movements may not disturb sleep, may cause awakenings that the person is aware of, or cause awakenings that the person is not aware of. If there are awakenings (aware or not), the person typically reports daytime tiredness or sleepiness and nonrestorative sleep. The cause of PLMD is unknown. Some physicians have suggested the same causes associated with RLS and additionally anemia, peripheral neuropathy (seen in diabetes) and use of antidepressants. Some suggest the movements are caused by reactions in the brain or spinal cord, or may be associated with circulatory problems.

The diagnosis of RLS is usually made by a physician based upon the symptoms. A diagnosis of PLMD is made based upon the results of a Polysomnogram, or commonly called a “sleep study”. During this test, the level of sleep is recorded (EEG-brainwaves) as well as leg muscle activity. Several other parameters are recorded (breathing effort, EKG, etc.). When the leg movements occur, it can be determined whether or not they are causing awakenings and what kind. This helps the physician determine a treatment plan.

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