Comparison of Source Characteristics between Typical and Atypical Rolandic Epilepsy in Childhood

Jung, Ki Young; Park, Sun Ah; Yoo, In Sool

Abstract

PURPOSE
has been reported that benign rolandic epilepsy of childhood (BRE) does not always show benign nature in a clinical course. We hypothesized that children with atypical feature showed different characteristics of dipole sources of rolandic spikes. METHODS: Twenty-nine children with BRE were enrolled. Twenty patients showed typical features of BRE (typical BRE group). Nine patients were classified as atypical BRE, because each met one or more of the following criteria:(i) neurodevelopmental abnormalities such as mental retardation or delayed development;(ii) abnormal neuroimaging findings; and (iii) poor seizure control. Routine waking and sleep EEG recordings were obtained for at least 30 min from each patients, using a 32-channel digital EEG machine. Centrotemporal spikes were averaged which was used to do dipole source localization. The source location was estimated within a four-shell ellipsoidal model of the head. Voltage topography, orientation and propagation pattern of dipole source, as well as clinical characteristics were compared between two groups. RESULTS: The clinical characteristics such as age, sex, seizure onset age, and seizure outcome were same in both groups. The negative maximum of spikes was mainly on the central and temporal electrodes in both groups. Two thirds of patients in each group demonstrated dipole sources with tangential orientation. 40% of the typical BRE revealed two sources indicating propagation of spikes around rolandic areas, which was not observed in atypical group. The pattern of propagation was mostly from tangential to radial in anterior direction. CONCLUSIONS: These results suggest that the pathophysiological mechanism generating centrotemporal spikes of atypical BRE is different from that of typical ones.