Infantile and early childhood epileptic syndromes

Abstract

In 1976, Ohtahara et al. described an epilepsy syndrome affecting very young infants with a suppression burst (SB) pattern on the EEG that frequently evolved into West syndrome and Lennox-Gastaut syndrome [1] and termed it “early infantile epileptic encephalopathy with suppression-burst” [2]. The eponym Ohtahara syndrome (OS) came into prominent use in the mid-1980s [3]. In 1978, early myoclonic encephalopathy (EME) was first described in neonates with erratic myoclonus and frequent focal seizures [4]. Numerous terms have been applied to this condition, including myoclonic epilepsy with neonatal onset, neonatal epileptic encephalopathy with periodic electroencephalogram bursts, and early myoclonic epileptic encephalopathy [5]. In 2001, the Task Force on Classification and Terminology of the International League Against Epilepsy recognizes two early-onset epileptic encephalopathies (EOEEs): early infantile epileptic encephalopathy (EIEE) (also called OS) and EME [6]. The term “epileptic encephalopathy” refers to conditions where the epileptic abnormalities themselves are believed to contribute to the progressive disturbance of cerebral function stipulating that early intervention may improve developmental outcome [6]. Nevertheless, several authors highlight that considering EOEEs as an epileptic encephalopathy is highly debatable because the neurological prognosis of these patients seems predominantly caused by the preexisting brain dysfunction [7-9]. Therefore, EOEEs are also called “catastrophic epilepsies” [10], “Genetic or acquired encephalopathies with epilepsy” [8], or “early-onset severe epilepsies with suppression burst” [9].