Approximately 4 percent of American adults suffer from
periodic limb movement disorder
(PLMD). The sleep disorder is characterized by the patient’s limbs (usually, one or both legs) involuntarily and rhythmically moving several times during the night. These movements differ from the normal spasms people experience as they begin to fall asleep. Side effects of PLMD include fatigue and excessive daytime sleepiness (EDS), as well as the interrupted slumber of the sleep partner who becomes an unintentional target of “kicky” legs, so treating this sleep disorder can improve one’s quality of life and relationship harmony.