Regional Connectivity Changes According to Seizure Outcome of Temporal Epilepsy Surgery: A Magnetoencephalography Study

Abstract

For patients with medically intractable temporal lobe epilepsy (TLE), anterior temporal resection has been mostly frequent treatment. However, there is a substantial variability in success rate of the surgery. Studies examining 1-year outcomes of TLE showed seizure free rate is largely 60 -80% [1,2]. Prediction of success after TLE surgery for each patient is often of a great issue and several studies addressed it. Clinical and neuroimaging factors predicting favorable outcome are focal findings of mesial temporal sclerosis seen either neuroimaging and pathologic finding, unilateral and less extensive hypometabolism on positron emission tomography (PET), neuropsychological findings suggestive of unilateral dysfunction ipsilateral to probable epileptogenic side, shorter duration, and absence of generalized tonic-clonic seizure history [3,4]. Unlike functional magnetic resonance imaging, electrophysiologic studies such as electroencephalography (EEG) and magnetoenecephalography(MEG) [1,4] techniques directly measure local field potential of electric brain activity [5].Despite of evidence that scalp EEG can be useful in predicting seizure outcome in epilepsy surgery, its utility is still uncertain due to limitation concerning low (up to 1 cm) spatial resolution and