Sleep Disorders Disrupted Periodic Limb Movement

Periodic limb movement disorder (PLMD) is a condition involving repetitive limb movements that disrupt sleep. PLMD usually affects the lower limbs from the hip to the big toe, but may also affect the upper limbs.

PLMD or Sleep Myoclonus?

Period limb movement disorder was originally called sleep myoclonus. A myoclonus is a sudden muscle contraction. The name was changed to periodic limb movement disorder because the sleep twitching associated with PLMD isn’t the sudden spasm seen with true myoclonus.

A condition called sleep myoclonus does exist. True sleep myoclonus is an unexpected muscle spasm that usually occurs just as the individual is drifting off to sleep. PLMD sleep twitching is less startling and occurs in light sleep.

Periodic Limb Movement Disorder Symptoms

The sleep twitching associated with PLMD is less noticeable than true sleep myoclonus, which awakens the sleeper. Periodic limb movement disorder sleep twitching does cause partial arousal, but the sleeper rarely notices this disturbance. Most people suffering from PLMD report excessive daytime sleepiness and insomnia to doctors, but not sleep twitching.

Periodic limb movement is characterized by repetitive extensions of the limb, most usually the big toe, ankle, knee or hip. The extension is repeated in regular intervals of anywhere from 5 to 90 seconds, according to the Cleveland Clinic (2009).

Sleep twitching associated with PLMD often disrupts a bed partner’s sleep as much, if not more, than the sleep of the person exhibiting periodic sleep movement disorder symptoms.

Causes of Periodic Limb Movement Disorder

The causes of periodic limb movement disorder remain unknown, although it may be related to restless leg syndrome. According to the Cleveland Clinic (2009), 80 percent of people with restless leg syndrome show signs of PLMD. However, the majority of people with PLMD don’t have RLS.

Periodic limb movement disorder symptoms may also occur in people with conditions such as:

  • Anemia
  • Attention deficit hyperactivity disorder
  • Diabetes
  • Narcolepsy
  • Parkinson’s disease
  • REM sleep behavior disorder
  • Sleep apnea
  • Spinal cord tumors
  • Uremia.

Some medications may be tied to PLMD symptoms, including some tricyclic antidepressants and antipsychotics, and antihistamines. Drug dependency and withdrawal from benzodiazepines or barbiturates are also potential triggers of PLMD.

In most cases, the cause of periodic limb movement disorder cannot be identified. Both children and adults develop PLMD symptoms, and the risk of PLMD increases with age. The American Academy of Sleep Medicine (2006) estimates that up to 34 percent of people aged 65 or older have some degree of periodic limb movement disorder.

Treating Periodic Limb Movement Disorder

The first step in treating periodic limb moment disorder is eliminating substances that can trigger sleep twitching. Avoid caffeine, a common PLMD trigger, and make sure that any medications you’re taking aren’t causing your symptoms.

Medical treatment for PLMD usually begins with Parkinson’s disease medication, such as Requip®. Your doctor may also prescribe anticonvulsants, benzodiazepines and narcotics. See a doctor for proper diagnosis and treatment.


American Academy of Sleep Medicine. (2006). Periodic limb movements. Retrieved August 23, 2010, from

Anderson, W. E. (2010). Periodic limb movement disorder. Retrieved August 23, 2010, from

Cleveland Clinic. (2009). What is periodic limb movement disorder (PLMD)? Retrieved August 23, 2010, from