Periodic Limb Movements of Sleep (PLMS)

What is periodic limb movements of sleep (PLMS)?

Periodic limb movements of sleep (PLMS) is a movement disorder that involves repetitive leg and/or arm movements during sleep. These movements can disrupt your sleep. Other names for this condition include sleep-related myoclonus syndrome or nocturnal myoclonus syndrome.

The movements usually involve your lower extremities, consisting of extension of your big toe and bending (flexion) of your ankle, knee and hip. In some cases, the movements can occur in your upper extremities as well.

PLMS often occurs alongside restless legs syndrome (80% to 90% of cases) or one of the following conditions:

• Obstructive sleep apnea.
• Narcolepsy.
• REM sleep behavior disorder.
• Uremia.
• Spinal cord tumor.
• ADHD.

What is the difference between periodic limb movement disorder (PLMD) and periodic limb movements of sleep (PLMS)?

Although they have similar names and the same symptoms, PLMD and PLMS are different. Healthcare providers diagnose PLMD when they can’t find any underlying condition that’s causing the movements. They diagnose the movements as PLMS if they happen alongside another condition.

PLMD is rare. PLMS is more common.

How common is periodic limb movements of sleep?

Researchers estimate that PLMD and PLMS affect 4% to 11 % of adults and 5% to 8% of children. Periodic limb movements are a common finding in sleep studies.

What are the symptoms of periodic limb movements of sleep?

People with PLMS typically seek medical care because they have sleep-related issues, such as:

• Daytime fatigue or sleepiness.
• Insomnia.

People with PLMS or PLMD have leg or arm twitches or jerks every 20 to 40 seconds during sleep. Most people with the condition don’t know they’re making the movements. But their bed partners may say that they kick while sleeping.

Some people with PLMS experience frequent awakenings and problems with sleep onset due to these movements.

What causes periodic limb movements of sleep?

Researchers don’t know the exact cause of PLMS. They think it might be due to an issue with or malfunction of your spinal cord that causes involuntary movements during sleep.

Several medications are known to make PLMS worse, including certain:

• Antidepressants, like mirtazapine, venlafaxine, sertraline, fluoxetine and amitriptyline.
• Antihistamines.
• Antipsychotics (neuroleptics).

What are the risk factors for periodic limb movements of sleep?

Any of the following conditions or situations may increase your risk of PLMS:

• Anemia.
• Being 65 or older.
• Diabetes-related neuropathy.
• Family history of restless legs syndrome, PLMS or PLMD.
• Obesity.
• Physical inactivity.
• Smoking.

How is periodic limb movements of sleep diagnosed?

Healthcare providers diagnose periodic limb movements of sleep (PLMS) based on your medical history and the results of an overnight sleep study (polysomnogram).

This is a test that tracks and records how multiple body systems work while you’re asleep. It involves sensors that track the activity of your heart, brain, respiratory system and other bodily functions. Providers diagnose PLMS in adults who have more than 15 limb movements an hour during sleep. They diagnose it in children who have more than five limb movements an hour.

Providers only diagnose PLMD if there’s no underlying cause of the movements, such as sleep apnea or restless legs syndrome. The sleep study can also test for several of these associated conditions. Your provider may order additional tests, such as blood tests, to rule out any other causes.

How is periodic limb movements of sleep treated?

There’s no specific treatment for PLMS. Healthcare providers typically prescribe medications that help treat restless leg syndrome. This is because it’s related to PLMS, and the medication may be effective for it as well. These medications include:

• Pramipexole.
• Ropinirole.
• Rotigotine.
• Gabapentin.
• Pregabalin.

Researchers are also studying the following medications for the treatment of PLMS:

• Clonazepam.
• Melatonin.
• Valproate.
• Selegiline.

If you’re taking an antidepressant or other medication that may be making PLMS worse, your provider may recommend switching to a different kind. Never stop taking prescription medications without talking to your provider first.

Can PLMS be prevented?

As researchers don’t know the exact cause of PLMS, there’s no known way to prevent it. Managing risk factors for the condition, such as quitting smoking or increasing physical activity, may reduce your chance of developing it.

What is the prognosis (outlook) for periodic limb movements of sleep?

PLMS mainly affects your quality of sleep and may disrupt your bed partner’s sleep.

There isn’t much research on the long-term effects of PLMS. But studies show that people who have sleep movement disorders (such as PLMS) tend to have high blood pressure. This may increase your risk of stroke and heart attack. Talk to your healthcare provider about how to manage this risk.

When should I see my healthcare provider about PLMS?

If you have PLMS, you should reach out to your healthcare provider if:

• You have new symptoms or your symptoms are getting worse.
• You’re experiencing bothersome side effects from PLMS treatment.

Is PLMS a precursor to Parkinson’s?

While people with Parkinson’s disease (PD) may have periodic limb movements during sleep as a part of PD, no research suggests that PLMS or PLMD (the disorder) are an early sign of Parkinson’s disease.

Is PLMS a neurological disorder?

Yes, researchers believe PLMS is a neurological disorder because an issue with your spinal cord (part of your nervous system) is likely the cause of the condition.

A note from Cleveland Clinic

If you’re having issues with sleep or with feeling well-rested, it’s important to talk to a healthcare provider. Quality sleep is crucial to your overall health. While it may be unlikely that the culprit is periodic limb movements of sleep (PLMS), your provider will order tests to be sure. If you have any questions, don’t hesitate to ask your provider. They’re available to help you.