Developmental outcome in benign myoclonic epilepsy in infancy and reflex myoclonic epilepsy in infancy: A literature review and six new cases

Abstract

Benign myoclonic epilepsy in infancy is a rare syndrome with just over 100 cases reported since the first syndromic description by Dravet and Bureau [Dravet, C., Bureau, M., 1981. The benign myoclonic epilepsy of infancy. Rev. Elecroencephalogr. Neurophysiol. Clin. 11, 438–444]. This includes 23 infants with reflex myoclonic epilepsy whose inclusion in the wider syndrome remains debatable. We have reviewed the literature and present data from six further cases. Prognosis in respect of long term seizure freedom is good with sodium valproate being the most effective medication. However, the cognitive outcome is much less certain with cognitive problems present in one-third of children who have long term follow up. The cognitive outcome in reflex myoclonic epilepsy of infancy is normal in all reported cases. The term benign may be appropriately used to describe the myoclonic seizures but must be used cautiously when counselling families about cognitive outcome. The clinical heterogeneity within this syndrome suggests that there may be a variety of genetic mechanisms that underlie the presentation. Clinicians should distinguish the syndrome of reflex myoclonic epilepsy in infancy from benign myoclonic epilepsy of infancy and all patients should continue developmental follow up for several years after diagnosis.