Benign neonatal sleep myoclonus. Relationship to sleep states.

Neonatal sleep myoclonus is a benign syndrome characterized by myoclonic jerks occurring only during sleep and presenting in the first month of life. There are no associations with abnormal development, neurologic deficits, or seizures. The electroencephalogram is normal and has no correlation with the myoclonic jerks. The myoclonus is present in all sleep states although its frequency is state dependent and greatest during quiet sleep. It is not associated with an arousal response as previously thought. Transient serotonin imbalance and genetic factors might play a role in the pathogenesis of this disorder.