Abstracts

Rationale: Atypical benign partial epilepsy in childhood (ABPE) is characterized by centro-temporal electroencephalography spikes, continuous spike and waves during sleep (CSWS), and multiple seizure types including epileptic negative myoclonus, but not tonic seizures. This study evaluated the localization of magnetoencephalography (MEG) spike sources to investigate the clinical features and mechanism underlying ABPE. Furthermore we conducted prospective cohort analysis to evaluate the population of ABPE among patients with CSWS. Methods: We selected all patients with CSWS among 1,500 new patients of our hospital from November 2000 to March 2013. Subjective patients were evaluated by multiple MEG study with 204ch gradiometers: VectorView System, Elekta Inc. Stockholm, Sweden. Equivalent current dipoles were calculated by dipole fitting software (xfit, Neuromag Oy, Helsinki, Finland). ABPE was defined by the concentrated MEG spike sources at peri-sylvian and peri-Rolandic area. We conducted a cohort study: subjective patients with ABPE were treated by Ethosuximide (ESM) and other drugs were eliminated. All drugs were stopped when the seizures were ceased more than 2 years. MEG analysis were conducted every once year or less. Results: Fifteen patients (male: 8; female: 7; 3 to 14 years old: mean 6.4 years old) were selected as patients with CSWS. Fourteen patients out of 15 patients with CSWS were diagnosed as ABPE by MEG and a patient was Landau-Kleffner syndrome. All patients with ABPE were included in our cohort study. The seizures of the patients were controlled by ESM by a year to 13 year (mean 6.5 years). Medication was stopped in 9 patients. MEG spike sources were consisted at peri-Rolandic or peri-sylvian area, and dismissed in 7 patients. Conclusions: We suspected that not all, but the most patients with CSWS were ABPE.