Introduction Restless legs syndrome (RLS) is a very common sensorimotor disorder usually associated with unpleasant sensations and characterized by an irresistible desire to move the legs . Symptoms occur during periods of rest, such as sitting or lying down, and are partially or totally relieved by movement. Restless legs syndrome worsens in the evening and night, delaying sleep onset and/or causing frequent awakenings, especially during the first part of nocturnal sleep . A variable RLS prevalence rate has been reported ranging from 4% to 29% of the general adult population, making it one of the most common sleep disorders [2,3]. Even the studies reporting lower prevalences suggest that close to 1 in 100 persons suffers from RLS that seriously impacts on quality of life, while 1 in 25 have symptoms causing at least some degree of distress. About 80%–90% of RLS patients also experience periodic limb movements (PLM) of sleep (PLMS). Periodic limb movements are involuntary, repetitive, and stereotyped short-lasting movements of the lower and sometimes upper limbs, often consisting of a dorsiflexion of the big toe with fanning of the small toes, accompanied by flexion at the ankles, knees, and thighs. Each movement lasts 0.5–10 s and recurs at intervals of 5–90 s, in a series of at least four such movements in sequence that are at least 8 μV in amplitude with a remarkable periodicity of approximately 20–40 s  (Figures 12.1 and Figures 12.2).
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