EEG-fMRI as an useful tool to detect epileptic foci associated with secondary bilateral synchrony

Abstract

Tailoring the epileptic cortex is the key issue in the pre-surgical work-up of patients with pharmacoresistant focal epilepsy. Not always, however, the conventional MRI and the scalp EEG are able to provide the information needed to address this issue since the imaging may be normal (criptogenetic epilepsy) and the EEG, even ictal, poorly localizing. We present a case of focal criptogenetic epilepsy with speech arrest seizures and bilateral synchronous spike and wave scalp EEG pattern (secondary bilateral synchrony). The patient underwent an EEG-fMRI continuous co-registration. The EEG-fMRI showed a clear cut activation of a BOLD signal during the epileptic discharge over the left Supplementary Motor Area (SMA) and, on lesser degree, over the homolateral motor strip. Knowledge and expertise about this technique has greatly increased over the last few years making it an useful tool for localizing purposes specially in patients with ambiguous scalp EEG and normal MRI just like the one we presented.