The literature on benign neonatal sleep myoclonus (BNSM) was reviewed and synthesized by researchers at University of Bern, Switzerland. The diagnostic criteria were neonatal onset, myoclonic jerks (sudden, brief, jerky involuntary movements) occurring only during drowsiness or sleep, cessation with arousal, and absence of concomitant epileptiform EEG activity. All articles published in English after the original description by Coulter and Allen in 1982 were analyzed. Based on 24 reports that included 164 term-(96%) or near term-born (4%) infants, BNSM occurred in all sleep stages, disappeared after spontaneous or provoked arousal, and was induced by rocking (7 cases) the infant or repetitive sound stimuli (8 infants). Jerks worsened by holding the limbs (5 reports) or by administration of antiepileptic drugs (33 cases). BNSM resolved by age <3 months in 64%, and by age <6 months in 95%; it persisted after 3 months of age in one-third of infants. Incidence is unknown but is estimated between 0.8 and 3.0 cases per 1000 births. A positive family history of BNSM was reported in 3 cases and parasomnias in 9 cases. Mothers had no history of illicit drug use. [1]

COMMENT. An awareness of the characteristics of benign neonatal sleep myoclonus and the clinical diagnosis should differentiate it from epilepsy. Parents may be advised to avoid unnecessary stimulation by rocking and noise and be reassured of an early spontaneous recovery.

Paroxysmal nonepileptic events in children and adolescents vary with age [2]. 1) Infant, Toddler, and Preschool Group (2 mos - 5 years; 26 patients), the most common diagnoses were stereotyped movements, hypnic jerks, parasomnias, and Sandifer syndrome (spasmodic torticollis, hiatus hernia, and gastroesophageal reflux). Concomitant epilepsy was present in 12 patients (46%); 2) The School-Age Group (5-12 years; 61 patients), Most common diagnoses were conversion disorder (psychogenic seizures), inattention or daydreaming, stereotyped movements, hypnic jerks, and paroxysmal movement disorders. Concomitant epilepsy in 15 patients (25%); 3) The Adolescent Group (12 - 18 years) 48 patients of whom 40 (83%) were diagnosed with conversion disorder. Nine (19%) had concomitant epilepsy. Conversion disorder was most common in the adolescent group and in females, whereas males predominated in the school-age group. Concomitant epilepsy with nonepileptic events occurred in all age groups.