Abstracts

Rationale: Catastrophic epilepsies (CE) are age-related epileptic syndromes characterized by a variety of behavioral seizure manifestations, distinctive electroencephalogram (EEG) patterns, and poor outcomes that often start in the neonatal period. As seizures in the newborn have generally been identified only by direct clinical observation, there is usually a lack of objectivity whether seizures are categorized as epilepsies or non-epilepsies. Methods: A major characteristic of neonatal seizures is electro-clinical dissociation and some electro-graphic seizures do not produce clinical symptoms. It is difficult to correctly identify real epilepsies or epileptic syndromes in the neonatal period without ictal EEG. Some epileptic syndromes starting in the neonatal period such as early myoclonic encephalopathy (EME), Ohtahara syndrome (OS), or migrating partial seizures in infancy (MPSI), are categorized as CE. A suppression-burst EEG pattern (SBP) is usually seen in neonates with serious brain damage or neonatal epileptic syndromes. Results: We will highlight our recent experience of CE in Japan and also propose a precise definition for SBP which has not correctly been identified in the literatures. We experienced 3 cases of OS, 2 cases of EME and a case of MPSI in this 7 yeras. We propose the tentative definition of SBP in OS as follows. The bursts must consist with high amplitude non-synchronized paroxysms like hypsarrhythmia and continue for 2 to 6 seconds. The suppression (low-amplitude) phase must show less than 10 ?V or flat tracing and continues for 3 to 5 seconds. Suppression and burst phases must appear alternately and regularly every more than five seconds. SBP should be seen in both during sleep and awake states and should not change according to sleep-wake cycle. Conclusions: Epileptic encephalopathies with SBP in neonatal period are known to evolve into relatively few types of epileptic syndromes. We will emphasize the importance of ictal EEGs for diagnosis and treatment of neonatal epilepsies and epileptic syndromes. The SBP in OS should be distinguished from SBP in EME.