Benign sleep myoclonus of infancy

Federica Provini MD (

Dr. Provini of the University of Bologna and IRCCS Institute of Neurological Sciences of Bologna received speakers' fees from Eisai Japan and Italfarmaco and consulting fees from Zambon.

Antonio Culebras MD, editor. (

Dr. Culebras of SUNY Upstate Medical University at Syracuse received an honorarium from Jazz Pharmaceuticals for a speaking engagement.

Originally released November 29, 1995; last updated April 25, 2020; expires April 25, 2023

This article includes discussion of benign sleep myoclonus of infancy, deep sleep myoclonus, and quiet sleep myoclonus. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


In this article, the author highlights the clinical characteristics of benign sleep myoclonus of infancy (BSMI), alternate name benign neonatal sleep myoclonus, a movement disorder that typically starts within the first 15 days of life, occurs during sleep, and consists of intermittent repetitive jerks of the limbs at two to three per second. It is often evoked by gently restraining the child. Benign sleep myoclonus of infancy is usually not associated with any other neurologic impairment and spontaneously subsides within the first year of life. Its importance lies in the differential diagnosis with the epileptic, especially myoclonic, seizures of infancy. Benign sleep myoclonus of infancy can be mistaken for neonatal seizures or even neonatal status epilepticus; the recognition of benign sleep myoclonus of infancy is imperative to avoid unnecessary diagnostic studies and treatments.

Key points


• Benign sleep myoclonus of infancy consists of myoclonic jerks that involve limbs, trunk, or the whole body, occurring in clusters during quiet NREM sleep and disappearing during wakefulness.


• Benign sleep myoclonus of infancy occurs in early life, typically from birth to six months of age.


• Benign sleep myoclonus of infancy is not associated with EEG abnormalities and occurs in otherwise neurologically normal children.


• Benign sleep myoclonus of infancy may be induced by repetitive sound stimuli and by gently restraining or by rocking the child, especially in a head-to-toe direction.


• Benign sleep myoclonus of infancy should be especially differentiated from the epileptic myoclonus that occurs during infancy, and requires no treatment.

Historical note and terminology

Benign sleep myoclonus of infancy was first reported in 1982 as benign neonatal sleep myoclonus (Coulter and Allen 1982).

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