Early epileptic encephalopathy with suppression burst electroencephalographic pattern - an analysis of eight Taiwanese patients

Early epileptic encephalopathy with suppression burst (SB) comprises two di stinct epileptic syndromes, early infantile epileptic encephalopathy (EIEE) and early myoclonic encephalopathy (EME). We reviewed etiologies, neurolog ical outcome and clinico-electroence-phalographic features of EIEE and EME. Chart records of early epileptic encephalopathy with SB from January 1997 to December 2000 were reviewed. These cases fulfilled the diagnostic criter ia of EIEE and EME. Totally eight patients (four females, four males) were enrolled. They consisted of three cases of EIEE and five cases of EME. The follow-up periods ranged from 6 to 30 months. For EIEE, two cases had migra tional disorders, and one was cryptogenic; for EME, three cases had non-ket otic hyperglycinemia (NKH), one was pyridoxine dependency and one was crypt ogenic. The main initial seizure patterns were tonic spasms in EIEE, and we re erratic myoclonus in EME. The age of seizure onset ranged from 26 h to 5 days after birth for EIEE, and 2 h to 7 days of life for EME. The SB patte rn in the electroencephalography (EEG) was noted mainly during sleep state in EME, but in both awake and sleep states in EIEE. Asymmetric SB pattern a nd background activities in EEG were found in migrational disorders. The EE G in all cases of EIEE changed to hypsarrhythmia at 4-6 months of age. In E ME, only the EEG in cases of NKH evolved to hypsarrhythmia. Response to ant i-convulsants was generally poor. All had severe psychomotor retardation. A lthough EIEE and EME share several common features, differences in terms of seizure seminology and evolution, EEG patterns and etiologies still exist. (C) 2001 Elsevier Science B.V. All rights reserved.