Periodic Limb Movement Disorder

Periodic limb movement disorder involves a rhythmic jerking of the legs and sometimes arms, which may result in poor quality sleep and daytime fatigue. Unlike restless leg syndrome, these movements are involuntary and usually take place when a person is asleep.

This condition most often occurs during the first half of the night while in the sleep stage known as non-REM (Rapid Eye Movement). These periodic movements only partially arouse the sleeper, but the effects of these partial awakenings contribute to poor sleep and health.

Periodic limb movement disorder is classified as a parasomnia or disorders of arousal. It can be categorized as either disruptive or non-disruptive. The majority of the time, legs movements are involved, however, arm movements cannot be excluded. These movements may also be associated with excessive daytime sleepiness or insomnia.


This disorder is characterized periodically by the dorsiflexion (upward flexing) of the great toe, foot, or a flexing of the entire leg, usually in 20 to 30 second intervals. Many times, people are unaware of these movements during sleep. Often the occurances are reported by a significant other or the person with this disorder may notice bed covers and sheets completely off the bed.

Individuals may experience excessive daytime drowsiness, difficulty falling asleep or waking up early. Periodic limb movement disorder, though minor in itself in many cases, often accompanies other more serious sleep disorders and should not be ignored.


Periodic limb movement disorder is a polysomnographically or sleep study determined diagnosis. If the sleep center physician feels the limb movements are causing disturbances during sleep, then a sleep study would be clinically indicated. People with periodic limb movement disorder often do not have restless leg syndrome.

Other conditions can also be misdiagnosed as restless leg syndrome or periodic limb movement. These conditions would include myoclonus, epilepsy, painful legs and moving toes syndrome, and nocturnal leg cramps. Patients with a history of renal failure, low iron or ferritin levels, and peripheral neuropathy often are aware of leg movements and discomfort during sleep.


After the diagnosis has been made, medications are commonly used to treat the periodic limb movement disorder if it is playing a role in fragmented sleep. Many medications are available and recommendations can be made at the time of the consultation visit and/or after the sleep study.