What is Periodic Limb Movement Disorder (PLMD)?

Periodic Limb Movement Disorder (PLMD) is a condition in which a person's legs or arms twitch or move involuntarily and periodically during sleep. PLMD is not the same as normal night muscle spasms, or jerks, that occasionally occur when a person is falling asleep. The limb movements typically occur 20 to 30 seconds apart, 5 or more times an hour, on and off throughout the night during periods of non-REM sleep. The rhythmic episodes usually involve a partial flexing of the big toe, ankle, knee, and occasionally, the hips.

PLMD may occur with other sleep disorders. It’s often linked with restless legs syndrome, but they are not the same thing. Restless legs syndrome is a condition involving strange sensations in the legs (and sometimes arms) while awake and an irresistible and voluntary urge to move the limbs to relieve the sensations. At least 80% of people with restless legs syndrome have PLMD, but the reverse is not true.

What are the symptoms of PLMD?

• The affected individual is usually unaware of the repetitive motion or the accompanying brief awakenings that disrupt sleep.
• People who have PLMD usually complain of difficulty in falling asleep, staying asleep, or staying awake during the day.
• They may have restless sleep, hot or cold feet, or hair wearing off their legs.
• Bed partners often report being kicked, fighting for bed covers, or being awakened by the movements.

How is PLMD diagnosed?

In making a diagnosis of PLMD, your doctor will ask you about your sleeping habits, how much sleep you get at night, if you wake up at night, and if you have Restless Leg Syndrome or similar symptoms. Your doctor will also want to know if you are having any emotional problems or are taking any medications that may be causing or the symptoms.

Your doctor may also order some tests, including blood tests or and a sleep test called polysomnography (PSG or NPSG).

How is PLMD treated?

If you are diagnosed with PLMD, your doctor may suggest changes to your sleep routines, prescribe dietary supplements or medications, or suggest changes to current medications.