Alaska Sleep Education Center

Periodic Limb Movement Disorder (PLMD) vs. Restless Leg Syndrome (RLS)

Posted by Jack Johnson on May 20, 2013 7:10:00 AM

PLMD Restless LegPeriodic limb movement disorder (PLMD) and restless leg syndrome (RLS) are sleep disorders that, at first glance, appear to be the same thing.

Both conditions are characterized by a sleeper not being able to keep still. However, the two sleep disorders are distinctly different.

Diagnosing which condition a patient might be suffering from is important is determining what the best course of treatment might be.

PLMD is a condition in which a patient’s limbs—usually, one or both legs—involuntarily and rhythmically move several times during the night. These movements are different from the normal spasms that might occur as someone tries to fall asleep; with PLMD, the movements cluster at periodic intervals during the first, non-REM stage of sleep. Periodic leg movement disorder suffers often do not know they have the condition.

Restless leg syndrome is characterized by the uncontrollable urge to move one’s legs (or in rare cases, other limbs or parts of the body). Sufferers of RLS (a nervous system disorder also known as Willis-Ekbom Disease) feel an uncomfortable sensation, an unexplained pain, or a crawling feeling in their legs during restful periods, including while trying to fall asleep.

The difference between these two sleep disorders is that PLMD is an involuntary action—the patient often sleeps (though sometimes not restfully) through an episode of leg movements. With RLS, however, patients are awake the whole time and are jerking or kicking their legs in an effort to overcome the discomfort their brains are perceiving. In other words, restless leg syndrome keeps the patient awake; periodic limb movement disorder occurs when the patient is already asleep.

Approximately 4 percent of adults have PLMD, with a higher rate occurring in elderly females. An estimated 10 percent of the population suffers some sort of RLS, with the disorder more frequent in middle-aged or senior adults. Interestingly, a study discovered that about 80 percent of restless leg syndrome patients also experience periodic limb movement disorder, but also that PLMD sufferers weren’t any more likely to have RLS.

Treatments for PLMD and RLS can differ, although some drug solutions do overlap for both disorders. The exact causes for each are unknown, though certain medications, Parkinson’s disease, and narcolepsy can trigger both disorders.

One similarity between PLMD and RLS that must not be overlooked: Fatigue and excessive daytime sleepiness (EDS) are side effects of both disorders. After all, restless leg syndrome prevents sufferers from falling asleep; periodic leg movement disorder can prevent sufferers from getting a good night’s sleep even after dozing off. Seeking a diagnosis and treatment is important not only for sufferers of these disorders, but also for sleep partners whose slumber is disrupted by the restlessness of the person beside them. Do you have questions about PLMD or RLS? Contact Alaska Sleep Clinic - we have answers.

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Topics: sleep disorders, plmd, tired, restless leg syndrome

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