Electrophysiological investigations in childhood epilepsy surgery

Epilepsy surgery in children is a functional surgery: its goal is to perform the resection of the epileptic brain tissue while sparing the eloquent cortex. Prolonged scalp video-EEGs allow recording of all types of seizures and play a crucial role in localizing the epileptogenic zone. Furthermore, EEG data correlation with clinical and radiological findings provides a guide for the surgical strategy: either resection without further investigations or an invasive recording procedure. In prehemispherotomy evaluation, EEG recordings confirm that limited resections are not indicated and demonstrate that the opposite hemisphere is not involved. If invasive recordings are needed, they consist in foramen ovale electrode insertion, which provides valuable information in mesial temporal lobe epilepsy, stereoelectroencephalography for children older than two years, and subdural grids associated with depth electrodes in infants or when the eloquent areas need to be carefully investigated. Such investigations allow tailoring surgery to each child.