Automatic detection of the HFO zone in epilepsy using magnetoencephalography

Introduction: This study combined the high spatial resolution of magnetoencephalography (MEG) with an automatic detector for an electrophysiological biomarker, high frequency oscillations (HFOs), to propose a hypothesis for the location of the epileptogenic zone (EZ) in epilepsy patients. The goal of this thesis was to increase the SNR of the signal to allow the use of an automatic detector to locate HFOs. Methods Resting state MEG data of 8 epilepsy patients was used. After determining the best settings for the beamformer and pre-processing techniques these settings were used to calculate virtual sensors (VS). These were used to optimize the HFO detector created by Burnos et al.. The last step in this thesis was the application of the optimized HFO detector to the total brain volume of one patient. Results No significant differences were found between the different beamformer settings. The cxSSS method proved to be superior. Application of the HFO detector to the total brain yielded a localization when only HFOs for a single moment in time were considered. Conclusion and discussion This study was the first to combine novel MEG techniques with an automatic HFO detector to localize the epileptogenic zone based on HFOs.