Childhood epilepsy

Abstract

Magnetoencephalography (MEG) is one of the best ways to analyze neural function. In particular, MEG is valuable for assessing brain activity in children with epilepsy, because it is noninvasive and can be used multiple times for the same patient, thus enabling changes in epileptogenicity to be monitored as a child’s growth. Conventional MEG analysis is not always able to define the epileptogenic area. To this end, the single-dipole analysis tools can resolve localized epileptic MEG discharges and demonstrate equivalent current dipoles (ECDs) in cerebral cortex. However, diffuse or multifocal epileptic activities are not suitable for such ECD analyses, because the formula underpinning the single-dipole method assumes a circumscribed epileptogenic area. In this chapter, we discuss an alternative MEG tool whereby spatial filtering analysis is used for widespread or multifocal epileptogenic areas. Furthermore, we performed time-frequency analysis on a patient with symptomatic localization-related epilepsy who showed rhythmic activities as subclinical electrical discharges. In conclusion, the single-dipole method, spatial filtering analysis, and time-frequency analysis could successfully resolve an epileptogenic area in patients with epilepsy. Thus, MEG analysis is potentially useful for presurgical evaluation or the diagnosis of epileptic syndromes for almost every patient with epilepsy.