Periodic Limb Movement Disorder

What Is Periodic Limb Movement Disorder?

Periodic limb movement disorder (PLMD) is characterized by repeated leg movements during sleep. Unlike restless leg syndrome, which occurs when a person is resting or trying to fall asleep, the movements of periodic limb movement disorder occur during sleep, and the person may be unaware of them. These movements may occur in the toes, feet, ankles and/or legs.

Roughly 4-11% of Americans are affected by periodic limb movement disorder, according to the National Institutes of Health. This disorder is common in older adults and in people with restless leg syndrome.

Periodic limb movement disorder is usually a chronic condition, though symptoms may fluctuate over time. Some people experience long symptom-free periods, while others have persistent sleep disruption.

Untreated periodic limb movement disorder can lead to chronic sleep fragmentation, resulting in:

• Daytime fatigue
• Difficulty concentrating
• Reduced quality of life

Periodic limb movement disorder should be distinguished from periodic limb movements in sleep (PLMS). People with PLMS experience repetitive, involuntary movements of the legs that occur during sleep. Many people with PLMS are unaware the movements are happening, but they can disrupt sleep quality. Periodic limb movement disorder is diagnosed when these movements are frequent enough to cause insomnia, poor sleep quality or excessive daytime sleepiness.

In other words, PLMS describes the movement pattern itself, while PLMD refers to a sleep disorder caused by those movements.

Signs and Symptoms

Because periodic limb movement disorder disrupts normal sleeping patterns, one of the most significant signs of the condition is daytime fatigue or sleepiness. Some of the other symptoms of periodic limb movement disorder can include:

• Insomnia
• Leg or arm twitches during sleep
• Repeated movement of toes or fingers during sleep

Because many of the symptoms of periodic limb movement disorder occur during sleep, most of the time it’s the sleeping partner who first notices the signs of the condition. However, if you find that you’re consistently fatigued during the day for unknown reasons, a sleep study can help with diagnosing periodic limb movement disorder.

Associated Conditions

Periodic limb movement disorder is more common in older adults and in people who already have restless legs syndrome. Low ferritin levels, even without anemia or low iron, are frequently associated with periodic limb movement disorder and should be evaluated. Certain medications, including some antidepressants and blood-pressure medicines, may trigger or worsen limb movements during sleep.

Periodic limb movement disorder is also seen more often in people with other sleep or neurologic conditions such as obstructive sleep apnea, narcolepsy or peripheral neuropathy. Identifying and treating these underlying issues is an important first step in management.

Diagnosis

A complete medical history is essential for diagnosis. If periodic limb movement disorder is suspected, your doctor will conduct a complete physical exam and ask you questions about your lifestyle, including:

• Family history
• Habits
• Hobbies
• Job or occupation
• Medications
• Symptoms

Several conditions can mimic or coexist with periodic limb movement disorder and should be considered during evaluation. These include restless legs syndrome, obstructive sleep apnea, REM sleep behavior disorder, narcolepsy and peripheral neuropathy. Treating one of these conditions, especially sleep apnea or iron deficiency, may significantly reduce limb movements during sleep.

It's important to keep track of when symptoms occur and what makes them better or worse, as well as any other sleep problems you are having.

Sleep Study

A sleep study, also called polysomnography, is a painless, noninvasive test that records your physical state during various stages of sleep. While a sleep study is not necessary for the diagnosis of periodic limb movement disorder, your doctor may have you undergo a sleepy study to check if your limbs are moving involuntarily while you are asleep.

A sleep study provides data essential in evaluating sleep and sleep-related complaints and problems. It can help in identifying:

• Blood-oxygen levels
• Body position
• Brain waves
• Breathing events
• Eye movement
• General sleep behavior
• Heart rate
• Muscle tone
• Sleep stages
• Snoring

Sleep studies are performed in either a sleep laboratory or at home. Most sleep studies take place at night. After you change into your nightclothes, the technician will connect you to a number of electrodes that will record your brain waves and muscle movements throughout the night. A microphone will record snoring, and two belt-like straps around the chest and lower abdomen will monitor chest and abdominal movements during breathing. Despite all of the equipment, most people ae able to sleep and complete a worthwhile study. After the technician is certain that electrodes are recording properly, the lights will be turned off and you can go to sleep. You will be able to talk to the technician, who will constantly monitor your test from an adjoining room. The technician will also help you if you need to use the restroom during the night.

You will be awakened in the morning, the electrodes will be removed, and you may shower and dress. Since the electrodes are applied with water-soluble glue or tape, removal is not painful. You will be asked to complete a questionnaire about your sleep the previous night, and then you can go home.

Your doctor will explain the results to you and talk with you about follow-up treatment, if required.

Treatment

In most cases, periodic limb movement disorder is a lifelong condition, though some people may go days or months without any symptoms.

For those people, or for others whose symptoms do not affect their quality of life, non-pharmaceutical treatments may be all they require. For people with more severe symptoms, medicines are available.

Medications

Medications used to treat restless leg syndrome are often prescribed by doctors to treat periodic limb movement disorder. Some medications can make this condition worse. These include some antihypertensive medications (taken for high blood pressure) and antidepressants. Your doctor may recommend you stop these medications and find alternatives that do not worsen your symptoms.

Over-the-counter medications such as acetaminophen or ibuprofen can be helpful in some people with periodic limb movement disorder. The medications most commonly prescribed for restless legs syndrome are dopaminergic agents and neuropathic medications.

Medications and Pregnancy

Although periodic limb movement disorder can often worsen — or appear for the first time — during pregnancy, doctors usually don't recommend taking drugs for periodic limb movement disorder during pregnancy. If the symptoms of periodic limb movement disorder are being caused by another disease, such as peripheral neuropathy or diabetes, treating the underlying disease may reduce the symptoms.

Lifestyle Management

Lifestyle management doesn’t cure periodic limb movement disorder, but it can reduce how disruptive symptoms feel and support better sleep overall — especially since periodic limb movement disorder is closely tied to sleep quality.

Reduce nighttime arousals that make periodic limb movement disorder more noticeable by:

• Addressing other sleep problems like insomnia or sleep apnea
• Exercising regularly, especially in the morning
• Keeping a consistent sleep schedule
• Limiting caffeine and alcohol (particularly in the evening)

Reviewing medications with a clinician is also important, because some antidepressants or other drugs can worsen limb movements. Finally, maintaining healthy iron levels, managing chronic conditions (such as diabetes or neuropathy) and practicing good sleep habits can make medical treatments more effective when they’re needed.

When to See a Specialist

It’s important to be evaluated by a sleep specialist if you or a loved one:

• Has symptoms of periodic limb movement disorder
• Would like to improve your current treatment of periodic limb movement disorder

At National Jewish Health in Denver, Colorado, we help hundreds of patients every year with sleep disorders. Learn more about our Sleep Center, or use the button below to make an appointment.