S16. The occurrence of nonepileptic events in children with intractable epilepsy: Findings from a single centre prospective audit

Abstract

Introduction Nonepileptic events are known to occur in persons with epilepsy, which could have a bearing on patient outcomes for those undergoing epilepsy surgery. Methods Over an 8 year period (2008–2017) 264 consecutive pediatric patients (age range 5 months to 17 years, mean 10.4 years, 145 males) were enrolled in our Children’s Epilepsy Surgery Service. Patients had been diagnosed with epilepsy on clinical and routine EEG grounds, and were deemed pharmaco-resistant based on their failure to respond to 2 or more anti-epileptic drugs at adequate doses for 6 months or more. As part of their pre-surgical work-up patients were admitted for 3–5 days of Video EEG (VEEG) monitoring to characterize their seizures, according to a standard recording protocol ( Pressler et al., 2017 ). Results We prospectively identified epileptic seizures in 224 children (85%), confirming the clinical diagnosis, and/or stereotypic nonepileptic events (NEE) without electrographic changes in 129 (49%). We excluded the usual paroxysmal events that can mimic seizures, including syncope, parasomnias, cardiac arrhythmia, and migraine. The videoed NEE were reviewed when appropriate with the patient’s parents or carers; confirmed as being habitual and that they had been erroneously attributed to ictal activity.This gave a VEEG-confirmed co-existence of epileptic seizures and NEE of 41%, compared to 10–50% in the Non-Epileptic Attack Disorder literature ( Francis and Baker, 1999 ). Conclusion We conclude that it is common to encounter concurrent epileptic and nonepileptic events in pediatric patients with medically intractable epilepsy. Our figure of 41% is higher than the reported occurrence of psychogenic nonepileptic seizures (PNES) in recent retrospective VEEG series of pediatric populations, when the clinical question was the differential diagnosis of epilepsy (33%) ( Szabo et al., 2012 ), including pre-surgical evaluations (19%) ( Riquet et al., 2011 ). Whilst not a contra-indication to epilepsy surgery per se the co-existence of NEE (or PNES) should be borne in mind when managing and counselling pediatric patients and their family or carers.