Sleep-related movement disorders
Periodic Limb Movement Disorder
Repetitive leg jerks or twitches during sleep that disturb sleep and cause daytime symptoms, often without the person being aware of them.
Overview
Periodic limb movements of sleep (PLMS) are repetitive movements, usually tightening or flexing of the legs, ankles or toes, that occur every 20 to 40 seconds in clusters during sleep. Many people have PLMS without any problem. Periodic limb movement disorder (PLMD) is diagnosed only when the movements are frequent and cause sleep disturbance or daytime impairment that is not better explained by another condition.
Most people do not know they are moving. Often a bed partner notices kicking, or the movements are found on a sleep study.
PLMS are very common in people with restless legs syndrome, narcolepsy and REM sleep behavior disorder, and become more common with age. When RLS is present, the diagnosis is RLS rather than PLMD.
Common symptoms
- Repetitive kicking or jerking of the legs during sleep
- A bed partner complaining of being kicked
- Unrefreshing or disrupted sleep
- Daytime sleepiness or fatigue
- Waking up with tangled sheets
Causes and risk factors
- Older age
- Iron deficiency
- Restless legs syndrome or narcolepsy (the movements occur alongside these)
- Certain antidepressants and antihistamines
- Chronic kidney disease
- Spinal cord conditions or neuropathy
How it is diagnosed
PLMD is diagnosed with an in-lab polysomnogram that records leg muscle activity. In adults, a periodic limb movement index of more than 15 per hour (more than 5 in children) is considered elevated. Diagnosis also requires clinically significant sleep disturbance or daytime impairment not explained by another sleep disorder, medicine or medical condition, and the absence of restless legs syndrome.
Treatment options
Treating iron deficiency
Correcting low iron may reduce movements.
Medication review
Stopping or changing medicines that increase limb movements, where possible.
Treating related conditions
Managing sleep apnea or other disorders that fragment sleep.
Medication in selected cases
Evidence is limited, and AASM 2024 guidance addresses PLMD separately from RLS; clinicians decide case by case.
What you can do yourself
- Limit caffeine and alcohol
- Keep a regular sleep schedule
- Ask a pharmacist whether your medicines could contribute
- Consider separate bedding if a partner's sleep is affected
When to see a doctor
- You feel unrefreshed despite enough sleep and a partner reports kicking
- Leg movements are accompanied by an urge to move in the evening
- Daytime sleepiness is affecting work or driving
Frequently asked questions
Is PLMD the same as restless legs syndrome?
No. RLS is a waking sensation and urge to move. PLMD involves movements during sleep. Most people with RLS have periodic limb movements, but if RLS is present the diagnosis is RLS rather than PLMD.
Are periodic limb movements always a problem?
No. Many people, especially older adults, have them without any sleep complaints. They are considered a disorder only when they disrupt sleep or cause daytime problems.
How would I know if I have it?
Usually a bed partner notices repetitive kicking, or it is detected on a sleep study. You may only notice poor sleep and daytime tiredness.
Can medicines cause leg movements in sleep?
Yes. Some antidepressants, antihistamines and antipsychotic medicines can increase periodic limb movements. Never stop a prescribed medicine without talking to your prescriber.
Sources
This page is general information, not a diagnosis or medical advice. Read our medical disclaimer.