Peripheral vasoconstriction in patients with sleep related periodic leg movements.

Two patients complaining of insomnia had sleep-related periodic leg movements (nocturnal myoclonus) on polysomnographic evaluation. Both also complained of cold feet and had abnormal peripheral pulse examinations. Treatment with phenoxybenzamine, alpha-adrenergic blocker, normalized the peripheral pulse responses, reduced the complaint of insomnia, and reduced the sleep related leg movements but resulted in only mild sleep improvements. Peripheral pulse examinations of ten other patients with sleep-related periodic leg movements revealed abnormal responses in four. From these and other results, it is hypothesized that the sympathetic nervous system may mediate the periodicity of sleep related periodic leg movements.