04-Local synchrony in EEG as a marker of epileptogenic zone

Abstract

Approximately a 1/3 of epileptic patients suffer from pharmacoresistant epilepsy. The surgery is often the only possible treatment, which brings a need for finding epileptogenic zone. The task is intricate in non-lesional patients in whom magnetic resonance imaging is uninformative. Our goal is to find a set of non-invasive imaging methods that would find the epileptogenic zone. We show first results with Local Synchrony (LS) method, that evaluates functional connectivity between cortical areas in short distances. We acquired high-density electroencephalography (HD-EEG) data from a set of 25 healthy control subjects (HC) and from a set of epileptic patients. We computed the Corrected Imaginary Coherence (CIC) in source space among all possible pairs of adjacent solution points. The CIC image from each patient was compared with the HC images to reveal regions with increased LS. We performed the analysis for 5 patients. In one patient, the revealed regions matched the neurologist’s opinion based on clinical evaluation. In others, increased LS showed regions that might be potential candidates for epileptogenic zone according to clinical evaluation. The evaluation of LS seems to be a useful method that might bring valuable information in the stage of finding the epileptogenic zone in epilepsy patients. Acknowledgement This study was supported by the project 17-32292A of the Czech Health Research Council and We also acknowledge the core facility MAFIL of CEITEC supported by the Czech-BioImaging large RI project (LM2015062 funded by MEYS CR).