Periodic limb movement disorder (PLMD) is a sleep disorder where the patient moves limbs involuntarily and periodically during sleep, and has symptoms or problems related to the movement. PLMD should not be confused with restless legs syndrome (RLS). RLS is characterized by a voluntary response to an urge to move legs due to discomfort. PLMD on the other hand is involuntary, and the patient is often unaware of these movements altogether. Periodic limb movements (PLMS) occurring during daytime period can be found but are considered as a symptom of RLS. Only PLMS during sleep can suggest a diagnosis of PLMD.Periodic limb movement disorder is characterized by recurrent episodes of frequent limb movements while sleeping. It mostly happens in the lower parts of the body like the toes, ankles, knees and hips. It can also, in some cases, appear in the upper extremities of the body. These movements can lead the patient to wake up, and if so, sleep interruption can be the origin of excessive daytime sleepiness.PLMD is characterized by increased periodic limb movements during sleep (PLMS), which must coexist with a sleep disturbance or other functional impairment, in an explicit cause-effect relationship. Usually, these involuntary movements come from lower extremities (including toes, ankles, knees, and hips), although they can also be observed in upper extremities, occasionally. PLMS seem to be common features within many people, and identifying whether or not these movements are clinically relevant for a distinct diagnosis of PLMD remains a challenge for clinical and scientific fields.
However, it remains insufficient evidences related to the efficacy of pharmacological treatment in PLMD, and its use has been based on the dopaminergic medication effect on RLS. Therefore, a careful clinical monitoring with any pharmacological use in PLMD is recommended. Epidemiology
PLMD is estimated to occur in approximately 4% of adults (aged 15–100), but is more common in the elderly, especially females, with up to 11% experiencing symptoms. PLMD appears to be related to restless legs syndrome (RLS) - a study of 133 people found that 80% of those with RLS also had PLMS. However the opposite is not true: many people who have PLMS do not also have restless legs syndrome.PLMD is an uncommon childhood disorder. Based on adult criteria and PSG analysis, studies showed prevalence of isolated PLMD in children population with no other comorbidity about 1.2 to 1.5%. There was also evidence for 5.6 to 7.7% of children with PLMI > 5/hr. Periodic limb movements during sleep are associated with a lower quality of life in children with monosymptomatic nocturnal enuresis

See also
Hypnic jerk
Restless legs syndrome

References


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