Abstracts

Rationale: To report frequency of subclinical seizures seen during intracranial EEG monitoring for epilepsy surgery in a pediatric population Methods: Retrospective chart review of patients who underwent intracranial EEG monitoring prior to resection of seizure focus from 2010 through 2014 at Boston Children's Hospital. Details regarding demographics, lesion type and location, seizure semiology and invasive EEG data were collected. Results: 44 patients underwent intracranial EEG monitoring during this period. Median age at time of surgery was 13.5 years (1.0-22.1) and 24 were female. Of the 44 patients monitored, 28 had electrographic seizures in addition to electroclinical seizures, while the remaining 17 had only electroclinical seizures. Subclinical seizures had onset from the temporal grid in 13, frontal grid in 8, occipital grid in 1 and multilobar in 6 patients. Six had no lesion on pre-operative MRI. Focal cortical dysplasia was the most common pathology, reported in 19 of the subclinical group. Other pathologies included gliosis in 8, tube in 1, tumor in 3, and isolated mesial temporal sclerosis in one. Conclusions: Electrographic , or "subclinical" seizures are common amongst pediatric patients undergoing intracranial EEG monitoring. There was no difference in underlying pathology or affected lobe between those patients with and without subclinical seizures Funding: None