Periodic Limb Movement Disorder

Malia Jacobson
Definition

Periodic Limb Movement Disorder (PLMD) is a sleep-related movement disorder characterized by repetitive leg movements during sleep. Though PLMD generally involves movements of the hip, knees, ankles and big toe, occasionally the arms are involved as well. These periodic movements can recur every 5 to 90 seconds during non-REM sleep.

What is Periodic Limb Movement Disorder?

Wondering why you kick in your sleep? Periodic Limb Movement Disorder (PLMD) is a sleep-related movement disorder characterized by repetitive leg movements during sleep. Though PLMD generally involves movements of the hip, knees, ankles and big toe, occasionally the arms are involved as well. These periodic movements can recur every 5 to 90 seconds during non-REM sleep.

This disorder was previously known as sleep myoclonus, but myoclonus is now understood primarily as a symptom of other sleep disorders like PLMD and restless legs syndrome. Hypnic jerks are another type of involuntary movement that can occur at sleep onset. While PLMD occurs during sleep, hypnic jerks happen during the transition into sleep.

Symptoms of Periodic Limb Movement Disorder

Most people with PLMD are not aware of the condition, because the movements are involuntary and occur during sleep. However, people with PLMD may experience the following symptoms:

How Common is Periodic Limb Movement Disorder?

Prevalence of PLMD in adults is around 4 percent , though rates are much higher in certain populations; it affects an estimated 30 percent of adults over 65. One study found two-thirds of elderly women had symptoms of PLMD.

This disorder commonly occurs in relation to another sleep disorder. According to Cleveland Clinic, up to 80 percent of patients with Restless Legs Syndrome have PLMD. The condition is also linked to a number of other sleep disorders and chronic conditions, including REM behavior disorder, narcolepsy, obstructive sleep apnea, diabetes, anemia and spinal cord injury.

What Causes Periodic Limb Movement Disorder?

The cause of PLMD is unknown. As with other sleep-related movement disorders, researchers believe that iron deficiency, dopamine regulation and genetic factors may contribute to PLMD.

Diagnosis

Physicians use medical history and symptoms to diagnose PLMD. Because PLMD often occurs with other sleep disorders, a polysomnogram may be performed to test for underlying sleep disorders like OSA. Healthcare providers may also request blood tests to check levels of thyroid hormone, iron and other nutrients.

Treatment

While there is no cure for PLMD, recommended treatments can help manage symptoms for deeper, more restorative sleep. People with PLMD may experience relief with lifestyle modifications. Natural remedies for periodic limb movement disorder include taking a warm bath (with or without epsom salts), taking a brief walk before bed, and light leg massage before bed.

Physicians often recommend avoiding caffeine and alcohol, which may worsen PLMD symptoms. Certain antidepressants may contribute to PLMD symptoms.

When PLMD is severe enough to disrupt sleep and contribute to excessive fatigue, medical interventions can help reduce or eliminate symptoms. Dopamine agonists are considered the most effective medication for treating PLMD. Anticonvulsants like gabapentin and benzodiazepines like clonazepam like sometimes used.

Additional Resources