Confirmation of Babinski-like response in periodic movements in sleep (nocturnal myoclonus)

Abstract

Periodic movements in sleep (PMS), also called nocturnal myoclonus, is a disorder of unknown etiology (Coleman 1982). It has been reported in association with many sleep disorders and has also been observed in asymptomatic persons (Bixler et al. 1978; Coleman et al. 1980). It is of importance clinically because it is responsible for 12% of all cases of insomnia (Coleman et al. 1982). The foot and leg movements in PMS are characterized by dorsiflexion of the ankle, extension of the great toe, extension and fanning of the small toes, and partial flexion of the knee and hip (Guilleminauh et al. 1975; Coleman et al. 1980; Smith 198.5); clonic movements about the ankle and toes have also been described (Lugaresi et al. 1968; Smith 1985). As these movements closely resemble the clinical Babinski response (Smith 198.5) and as PMS (Coleman 1982) and the normally occurring nocturnal Babinski response (Fujiki et al. 1971) are phenomena of NREM sleep, the author recently proposed that the foot and leg movements of PMS are Babinski-like responses due to changes in the pyramidal tracts during NREM sleep (Smith 1985). The conclusion that these foot and leg move-