[Periodic limb movement disorder].

The periodic limb movements (PLM) are defined as stereotyped, periodic movements of the legs and/or upper limbs during sleep. The patient exhibits dorsifilexion of the ankle and extension of the big toe with occasional flexion of the knee and hip. PLM originally was described as "nocturnal myoclonus" by Symonds in 1953. Recently, the term "nocturnal myoclonus" has been replaced with PLM, because the movements are slower than true myoclonic movement. The appearance of PLM was reported in sleep apnea syndrome, delayed sleep phase syndrome, narcolepsy, spinal cord tumor, diabetes mellitus and uremia. The prevalence of PLM statistically increase with age. Patients with PLM show excessive daytime sleepiness or insomnia. Several reports show the difficulty recognizing periodic limb movement disorder (PLMD) without polysomnography (PSG). The diagnosis of PLMD is established only by PSG.