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Free keywords:
Ictal onset zone; Lennox-Gastaut syndrome (LGS); Directional connectivity analysis; Directed transfer function (DTF); Intracranial electroencephalography (iEEG); Ictal epileptiform activity
Abstract:
Introduction
Neuroscientists are becoming interested in the application of computational EEG analysis to the identification of ictal onset zones; however, most studies have focused on the localization of ictal onset zones in focal epilepsy. The present study aimed to estimate the ictal onset zone of Lennox-Gastaut syndrome (LGS) with bilaterally synchronous epileptiform discharges from intracranial electroencephalography (iEEG) recordings using directional connectivity analysis.
Methods
We analyzed ictal iEEG data acquired from three LGS patients who underwent epileptic surgery with favorable surgical outcomes. To identify the ictal onset zones, we estimated the functional directional connectivity network among the intracerebral electrodes using the directed transfer function (DTF) method.
Results
The analysis results demonstrated that areas with high average outflow values corresponded well with the surgical resection areas identified using electrophysiologic data and conventional neuroimaging modalities.
Discussions
Our results suggest that the DTF analysis can be a useful auxiliary tool for determining surgical resection areas prior to epilepsy surgery in LGS patients. This is the first research article demonstrating that directional connectivity analysis of iEEG recording data can be used for delineating surgical resection areas in generalized epilepsy patients who need surgical treatment.
