Localisation of Focal Epileptic Activity in Children Using High Density EEG Source Imaging*

In children suffering from epilepsy, a better understanding of the brain networks involved in epileptic activity is of great clinical and scientific importance. Non-invasive mapping of the epileptic focus can be performed with EEG source imaging (ESI), a technique based on scalp EEG recordings to estimate the localisation of the intra-cerebral electric sources. Recent technological development now allow recording high density EEG with only a short preparation and recording time (ca. 30 minutes in total) making this technique particularly suitable for clinical use in children, even when awake or very young. In children suffering from medically refractory focal epilepsy, ESI is often highly concordant with the epileptogenic zone and can be used in epilepsy surgery to improve the chance of post-operative seizure freedom, provided a sufficient number of electrodes is used, as routinely performed in our centre. More globally, the mapping of onset and propagation of epileptic discharges helps better understanding the pathophysiology of certain epileptic conditions and the potentially associated neurological and cognitive dysfunction. In this article, we present the methodological background and clinical studies of ESI and concordance with other imaging techniques in pediatric epilepsy.