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To study the role of magnetoencephalography (MEG) in the surgical evaluation of children with recurrent seizures after epilepsy surgery. We studied 17 children with recurrent seizures after epilepsy surgery using interictal and ictal scalp EEG, intracranial video EEG (IVEEG), MRI, and MEG. We analyzed the location and distribution of MEG spike sources (MEGSSs) and the relationship of MEGSSs to the margins of previous resections and surgical outcome. Clustered MEGSSs occurred at the margins of previous resections within two contiguous gyri in 10 patients (group A), extended spatially from a margin by ≤3 cm in three patients (group B), and were remote from a resection margin by >3 cm in six patients (group C). Two patients had concomitant group A and C clusters. Thirteen patients underwent second surgeries. IVEEG was used in four patients. Six of seven patients with group A MEGSS clusters did not require IVEEG for second surgeries. Follow-up periods ranged from 0.6 to 4.3 years (mean: 2.6 years). Eleven children, including eight who became seizure-free, achieved Engel class I or II. Our data demonstrate the utility of MEG for evaluating patients with recurrent seizures after epilepsy surgery. Specific MEGSS cluster patterns delineate epileptogenic zones. Removing cluster regions adjacent to the margins of previous resections, in addition to removing recurrent lesions, achieves favorable surgical outcome. Cluster location and extent identify which patients require IVEEG, potentially eliminating IVEEG for some. Patients with remotely located clusters require IVEEG for accurate assessment and localization of the entire epileptogenic zone. [ABSTRACT FROM AUTHOR]

Abstract Objective Limited evidence on the relationship between antiepileptic drug (AED) tapering and the likelihood of a seizure during an Epilepsy Monitoring Unit (EMU) admission is available, and no evidence specific to the pediatric population has been published. Our study sought to determine whether AED tapering leads to increased seizure likelihood in a pediatric EMU setting. Methods We performed a retrospective chart review of children admitted to the pediatric EMU at the Hospital for Sick Children in Toronto between June 1, 2014 and June 1, 2016. Data collected included demographics, reason for EMU referral, and epilepsy and medical characteristics. Among those with nondaily seizures, Kaplan–Meier curves were fit to compare probability of EMU seizure in those who were tapered fully from at least one AED to those not tapered. A Cox proportional hazards model was fit to evaluate this relationship after adjustment for subject sex, distance traveled to hospital, epilepsy duration, seizure frequency, time since last seizure, whether EMU referral was part of presurgical planning, magnetic resonance imaging (MRI) findings, and number of prescribed AEDs. An interaction between medication taper and number of prescribed AEDs was also included. Terms not significant at p < 0.3 were removed from the model, and the reduced model was recomputed. Results Of the 281 children included in the study, 159 had nondaily seizures. Kaplan–Meier curves indicated fully tapering at least one AED was associated with increased likelihood of seizure during EMU; however, after adjustment for confounding variables, this association was not preserved. Abnormal MRI findings, referral for presurgical evaluation, and shorter (≤ 3 months) time since last seizure were associated with increased likelihood of seizure during EMU. Significance Short-term AED tapering in pediatric patients may not be effective for increasing seizure likelihood in the EMU. Highlights • Evaluates the efficacy of AED tapering in a pediatric EMU setting • Fully tapering AED(s) in EMU patients was not associated with seizure likelihood. • Associated factors: MRI findings, presurgical referral, and time since last seizure [ABSTRACT FROM AUTHOR]