Restless legs syndrome and periodic limb movements in sleep

A strange thing happened on the way to understanding periodic leg movements in sleep (PLMS). The striking PLMS patterns of repetitive, short activations of anterior tibialis on an electromyography often accompanied by brief electroencephalogram (EEG) arousal certainly seemed to be a potent source of sleep disruption. A periodic limb movement disorder characterized by PLMS and sleep-wake complaints is defined to recognize the presumed sleep-disrupting effects of PLMS and is reported to be a common cause of insomnia and daytime sleepiness. Thus, PLMS are more important as markers of disease and its severity than as disrupters of sleep. Periodic limb movement disorder is rare if it exists. Despite the multiple causes for the pathology producing PLMS, these movements remain an important, easily measured marker of the functioning of subcortical dopamine systems. As a motor sign, they provide both an objective basis for confirming suspected diagnoses and an objective marker of the degree of the dysfunction. This is particularly useful for restless legs syndrome.