Periodic limb movement disorder (PLMD)
What is periodic limb movement disorder?
Periodic limb movement disorder (PLMD) is a condition where one leg or both legs move repeatedly during the night - which can disturb sleep.
The legs move every 20-40 seconds and this is more likely to happen earlier in the night.
The condition is common - affecting around half of people over 65.
What causes PLMD?
Doctors don't yet know what causes the condition. However, the symptoms may be caused by some health conditions, including diabetes, Parkinson's disease and narcolepsy.
The symptoms may be worse when taking some medications.
How is PLMD diagnosed?
A person with the condition may not know they have it until a partner tells them about it.
Doctors will diagnose the condition based on the reported symptoms, the person's medical history and a physical examination.
They may make a referral to a special sleep centre for an overnight polysomnogram test to record sleep and the bioelectrical signals from the body during sleep.
Bleed tests may also be arranged to check for other possible causes or the symptoms.
How is PLMD treated?
Mild cases of PLMD may not need treatment.
There is no cure for PLMD, but if the symptoms are causing problems, a doctor may recommend treatment using Parkinson's disease drugs, anticonvulsant medications, benzodiazepines, or narcotic drugs.
These treatments will need to be continued to keep symptoms under control.
Are there substances that should be avoided?
In some cases, PLMD symptoms may be made worse by caffeine and some antidepressants.
Reducing caffeine may help reduce symptoms, and if a medication side-effect is suspected, talk to your doctor about whether a different treatment is available.
Hypnic jerk is another type of involuntary limb movement during sleep which may be experienced. This muscle contraction is also known as hypnic myoclonia, nocturnal myoclonus or sleep jerks. These hypnic jerks may disturb the sleep of a partner, but are common and are not usually a cause for concern.