Abstracts

Rationale: Rasmussen's encephalitis is a rare disorder characterized by intractable focal epilepsy, progressive neurological deterioration, and unilateral hemispheric atrophy and has the natural course including prodromal phase, acute disease, and residual stage. The purpose of this study was to describe the characteristic electroencephalographic features in Rasmussen's encephalitis by stage. Methods: Patients diagnosed with Rasmussen's encephalitis at Seoul National University Children's Hospital were retrospectively assessed. We analyzed the background activities and epileptiform discharges from electroencephalography (EEG) findings to identify the characteristic EEG features by stage. Results: Seven patients were included in the study. The mean age of first seizure onset was 6.7 years, and the mean duration of the prodromal phase was 21.4 months. During disease course, background activities, such as slow waves, were more prominent and diffuse, and contralateral slow waves were observed. In most patients, focal epileptiform discharges were observed during all stages without change. Conclusions: As Rasmussen's encephalitis progresses, background abnormalities in the affected hemisphere increased, and contralateral slow waves occurred. However, characteristic EEG findings that were distinguishable at each stage were not observed.