S149 Video-EEG monitoring in young children

Abstract

Video-EEG monitoring, the synchronous recording of the ictal EEG pattern and the paroxysmal behaviour, is used to confirm the epileptic origine, to classify the seizure type(s) and the electro-clinical syndrome, and to assess seizure frequency and eventual precipitating factors. It is an essential diagnostic procedure in the presurgical evaluation of children with refractory focal epilepsy, in order to establish surgical candidacy, and to define localization and extent of the epileptogenic zone and its relationship to eloquent function. Although it is preferable to record seizures without modifying the anti-seizure medication, treatment reduction may be necessary along with other provocative procedures as i.e. sleep deprivation. Interpretation is based on the seizure semiology, the localization of the onset of the ictal discharge, EEG and clinical symptoms in the postictal phase, and the interictal EEG anomalies. Additional electrodes to the usual 10/20 system may be indicated, particularly important in mesial temporal discharges, using inferior temporal and anterior temporal surface electrodes. Refractory epilepsy in the pediatric population represents a particular challenge because of the wide variety of etiologies compounded to the brain maturation, very fast during infancy and early childhood, leading to a complex evolution of the clinical presentation. Especially genetically determined epilepsies may mimick structural focal epilepsies. Video-EEG recording is still the most widely available and useful test in evaluating the candidacy for a surgical treatment, with however limitations as imprecise localization or inability to detect deep or tangentially orientated foci. Therefore presurgical evaluation is multimodal combining scalp video EEG recording, electrical and magnetic source imaging, anatomical MRI, Arterial Spin Labelling (ASL) MRI, EEG-triggered functional MRI, and FDG-PET studies.