What Are Sleep-Related Movement Disorders?

Sleep-related movement disorders are a group of sleep disorders that cause body movement or muscle sensations during or just before sleep. These movements and sensations may make it hard to fall asleep or stay asleep.^1,2

Doctors consider these movements simple, such as leg or arm twitches. This compares to sleepwalking or sleep eating, which are a complex type of movement.

These disorders are diagnosed when the person complains to their doctor about not being able to sleep well. When asked, they often report bothersome symptoms like grinding their teeth, body rocking, kicking in their sleep, leg cramps, or uncomfortable sensations in their legs in the evening. Other signs of sleep-related movement disorders include fatigue, daytime sleepiness, and trouble concentrating.²

What causes sleep-related movement disorders?

Some of these sleep disorders run in families. Other times, diet, caffeine, alcohol, and legal and illegal drugs may trigger symptoms or make symptoms worse. Certain health conditions, such as brain injury, stress, or another neurological condition, may cause a sleep-related movement disorder.^1,2,5

Types of sleep-related movement disorders

There are 5 main types of sleep-related movement disorders:

Bruxism

Bruxism is the medical term for grinding or clenching teeth while sleeping. Left untreated, this can cause loose teeth, worn tooth enamel, headaches, and pain in the jaw and face. Fewer than 1 in 10 adults grind their teeth at night, but about 1 in 5 children under age 11 do.^2,3

Night leg cramps

Night leg cramps cause sudden, intense pain, usually in the lower leg or foot. These muscle contractions may happen when the person is awake or asleep and last an average of 9 minutes. Many people feel pain after the cramping passes. Episodes may happen every few years or every night. Six out of 10 adults reports night leg cramps at least once in their life. Only 2 out of 10 have symptoms bad enough to talk with their doctor.²

Periodic limb movement disorder

Periodic limb movement disorder (PLMD) causes uncontrollable, repeating muscle movements that may wake you up. With PLMD, the legs, and sometimes arms, twitch or jerk every 15 to 40 seconds, sometimes all night. PLMD is common in people who have other sleep and neurological disorders such as restless legs syndrome, sleep apnea, narcolepsy, and Parkinson’s disease.⁴

Restless legs syndrome

Restless legs syndrome (RLS) causes aching, burning, itching, or tingling feelings inside the legs, usually in the late afternoon and evening. These sensations can make it hard to fall asleep or stay asleep since getting up and moving the legs, such as with walking, is the only thing that brings relief. It is also called Willis-Ekbom disease. Up to 1 in 10 adults have RLS. It is more common in women than men. Many people with RLS also have periodic limb movement disorder.^4,5

Sleep rhythmic movement disorder

Sleep rhythmic movement disorder causes repeating body movements while asleep or falling asleep. The movements may look like side-to-side body rocking, head rolling, head banging, or rocking on the elbows and knees. These movements usually occur when the person is falling asleep or during sleep. It is more common in infants, children, and people with intellectual development disorders. It may appear and disappear in children.²

Research into sleep-related movement disorders

More than 200 studies were underway in 2020 to learn more about sleep-related movement disorders. Restless legs syndrome is the most studied of these conditions, by far. Researchers are studying new and existing drugs and other treatments that may help people with these sleep problems.⁶

Other types of sleep disorders include:

• Insomnia
• Sleep-related breathing disorders such as sleep apnea
• Hypersomnias such as narcolepsy
• Parasomnias such as sleepwalking, sleep eating, and bedwetting
• Circadian rhythm disorders such as shift-work disorder