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A condition characterized by persistent spasms (SPASM) involving multiple muscles, primarily in the lower limbs and trunk. The illness tends to occur in the fourth to sixth decade of life, presenting with intermittent spasms that become continuous. Minor sensory stimuli, such as noise and light touch, precipitate severe spasms. Spasms do not occur during sleep and only rarely involve cranial muscles. Respiration may become impaired in advance cases. (Adams et al., Principles of Neurology, 6th ed, p1492; Neurology 1998 Jul;51 (1):85-93)