Periodic Limb Movement Disorder

Some movement during sleep is normal, especially as you get comfortable or start to fall asleep. For example, most people have experienced “sleep starts” or hypnic jerks, a harmless phenomenon that causes their body to jolt suddenly as they fall asleep. Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source

But once you enter deeper stages of sleep, your body should stay mostly still. Repeated episodes of twitching, kicking, or flailing, especially at regular intervals, may indicate a sleep-related movement disorder like periodic limb movement disorder (PLMD).

What Is Periodic Limb Movement Disorder?

When you have periodic limb movement disorder (PLMD), your limbs twitch and jerk in a repetitive pattern while you sleep. These movements are called periodic limb movements of sleep (PLMS) and, while they can happen in the arms, they most often affect the legs. These movements usually happen every 20 to 40 seconds and can include: Trusted Source Merck Manual First published in 1899 as a small reference book for physicians and pharmacists, the Manual grew in size and scope to become one of the most widely used comprehensive medical resources for professionals and consumers. View Source

• Flexing the ankle so your big toe pulls up and back toward your leg
• Bending the legs at the knees or hips
• Twitching or kicking the legs

Most people don’t wake up when they move, but the movements can still disrupt sleep. These movements mostly occur during lighter stages of sleep. They may fragment sleep without fully waking you up, which can reduce deep, restorative slow wave sleep.

How Common Is PLMD?

Periodic limb movement disorder happens in 5 to 8% of children and 4 to 11% of adults. Under age 40, having more than five limb movements per hour is rare. The prevalence increases with age, especially after the age of 65, where PLMD may affect up to 25 to 30% of individuals.

What Causes PLMD?

Experts don’t know the exact cause of periodic limb movement disorder, but some research suggests low iron levels could play a part. Trusted Source Clinical and Translational Neuroscience View Source Problems with dopamine, an important brain messenger (neurotransmitter) may also prompt movements during sleep. Having too little dopamine can make your spinal nerves more sensitive and excitable, which creates a pathway for movement, especially during non-rapid eye movement (NREM) sleep.

PLMD may also be linked to disruptions in the brain’s central nervous system pathways that control motor activity. In some cases, PLMD appears after spinal cord injury or other neurological changes.

Risk Factors for PLMD

Although the causes of PLMD are still theoretical, studies have revealed that some factors can increase your risk for this movement disorder: Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source

• Restless legs syndrome (RLS): Over 30% of people with restless legs syndrome also have PLMD.
• Neurological conditions: Parkinson’s disease can increase your risk for PLMD.
• Sleep disorders: PLMD is more common in people with narcolepsy, rapid eye movement (REM) sleep behavior disorder, and obstructive sleep apnea (OSA).
• Family history: PLMD may have a genetic component and runs in families.
• Medications: Some antidepressants and antipsychotics can cause PLMS.
• Age: Limb movements in PLMD can happen more often with age.
• Inactivity and obesity: People who are overweight or sit down for much of the day may experience more nocturnal movement. 

Complications of PLMD

When periodic limb movements interrupt your sleep throughout the night, they can lead to complications. People with PLMD have more mood disorders, anxiety, attention problems, oppositional behavior, and parasomnias (like sleep talking or walking).

In children, missing sleep from PLMD can lead to hyperactivity and developmental delays. In adults, studies suggest PLMD is associated with a four-fold increased risk of dementia.

“Untreated PLMD can also contribute towards cardiovascular strain due to repeated micro-arousals and surges in blood pressure during the night. This may increase long-term risk of hypertension or heart disease.”

Lulu Guo, MD

Sleep Medicine Physician

What Are the Symptoms of PLMD?

Beyond the movements themselves, periodic leg movement disorder can cause other symptoms:

• Disturbed sleep
• Waking up with movement
• Insomnia
• Excessive daytime sleepiness
• Bed partner disruptions
• Anxiety
• Attention difficulties
• Poor performance at work or school

How Is PLMD Diagnosed?

Doctors diagnose periodic limb movement disorder by confirming a high number of periodic limb movements during sleep on a sleep study and ruling out other conditions that could cause those movements. If you suspect you have PLMD, your doctor may begin by asking questions about daytime tiredness, reports from your sleeping partner, and other indicators of PLMD.

To diagnose PLMD, you must have the following characteristics: Trusted Source UpToDate More than 2 million healthcare providers around the world choose UpToDate to help make appropriate care decisions and drive better health outcomes. UpToDate delivers evidence-based clinical decision support that is clear, actionable, and rich with real-world insights. View Source

• More than 15 limb movements per hour during sleep (adults)
• More than 5 limb movements per hour during sleep (children)
• Associated daytime sleepiness or functional impairment for example poor performance at work or school or in social settings

To see how many movements you have each night, your doctor may recommend a sleep study (polysomnography). During a sleep study, you will spend the night in a medical office, and the clinical staff will observe your movements. With these results and your other reported symptoms, they can then give you a PLMD diagnosis after ruling out any other potential causes, like low iron levels (anemia).

“Video monitoring during a sleep study may also reveal movements and help distinguish PLMD from seizure disorder or other other sleep related movement disorders.”

Lulu Guo, MD

Sleep Medicine Physician

What Are the Treatments for PLMD?

Treatments for PLMD depend on the cause, and research is limited on treatment for PLMD on its own. For example, periodic leg movements of sleep associated with RLS follow RLS treatments. Sometimes, PLMD doesn’t need treatment at all. 

If your iron levels come back low, your doctor may prescribe iron replacement. Some limited sleep study research has shown fewer nighttime movements with these medications that affect dopamine and nerve activity:

• Pramipexole (Mirapex)
• Ropinirole (Requip)
• Rotigotine (Neupro)
• Gabapentin (Neurontin)
• Pregabalin (Lyrica)

Other studies suggest that clonazepam (Klonopin), valproate (Depakote), and selegiline (Zelapar) may lessen nighttime waking, but more research is needed to prove the effectiveness of these medications against PLMD. 

Some research suggests exercise therapy and psychotherapies like cognitive behavioral therapy (CBT) can also improve PLMD symptoms. Trusted Source Medscape Medscape is on online destination for healthcare professionals worldwide, offering expert perspectives, drug and disease information, and professional education. View Source In addition to other treatments, you can improve your sleep by adopting good sleep hygiene, like keeping a consistent sleep schedule, avoiding alcohol and caffeine before bed, and making your sleep space cool, comfortable, quiet, and dark.

Still have questions? Ask our community!

Join our Sleep Care Community — a trusted hub of sleep health professionals, product specialists, and people just like you. Whether you need expert sleep advice for your insomnia or you’re searching for the perfect mattress, we’ve got you covered. Get personalized guidance from the experts who know sleep best.