Magnetoencephalographic Characteristics of Cortical Dysplasia in Children

Publication date: Available online 19 September 2017
Source:Pediatric Neurology
Author(s): Nitin Agarwal, Balu Krishnan, Richard C. Burgess, Richard A.Prayson, Andreas V. Alexopoulos, Ajay Gupta
Background & RationaleMagnetoencephalography (MEG) has emerged as a tool for pre-surgical evaluation in children. We aimed to study MEG characteristics in sub-types of Focal Cortical Dysplasia (FCD) and correlate with post surgical seizure outcome.MethodsInclusion criteria were children ≤18 years who had MEG during pre-surgical workup followed by epilepsy surgery and a histopathological diagnosis of FCD between February 2008- February 2013. Patient demographics, MRI, video EEG and MEG data were reviewed. Postsurgical seizure outcome data was categorized per ILAE definitions.ResultsOf 178 MEG performed in children during the study period, 33 patients met inclusion criteria. FCD Type I, II and III were found on histopathology in 52%, 39% and 9% patients respectively. Thirty patients had positive MEG dipoles including all patients with FCD Type II and III and 82% patients with FCD Type I. Three patients had MEG unique spikes. Brain MRI lesions were noted pre-operatively in 21 (64%) patients. Twenty-three (77%) patients had surgical resection of MEG dipoles and 11 (48%) of these achieved favorable outcome.ConclusionsMEG supplements scalp EEG data in spike source localization and showed unique spikes in 10% of the FCD patients. MEG spikes and tight MEG clusters were found more frequently in patients with FCD Type II and III as compared to FCD Type I. Presence of a MRI lesion and complete vs incomplete resection of MEG cluster did not result in significant difference in postsurgical seizure outcome likely reflecting selection bias of doing MEG in only difficult to localize epilepsies.



http://ift.tt/2xQSml2