Imaging the extent and location of spatiotemporally distributed epileptiform sources from MEG measurements

Highlights • Evaluation of epilepsy source extent estimation from MEG measurements. • FAST-IRES gave robust location and extent estimation under different noise levels. • Epileptic sources were estimated from interictal discharges in drug-resistant epilepsy patients. • FAST-IRES outperformed LCMV in both simulation and patient data analysis.
Non-invasive MEG/EEG source imaging provides valuable information about the epileptogenic brain areas which can be used to aid presurgical planning in focal epilepsy patients suffering from drug-resistant seizures. However, the source extent estimation for electrophysiological source imaging remains to be a challenge and is usually largely dependent on subjective choice. Our recently developed algorithm, fast spatiotemporal iteratively reweighted edge sparsity minimization (FAST-IRES) strategy, has been shown to objectively estimate extended sources from EEG recording, while it has not been applied to MEG recordings. In this work, through extensive numerical experiments and real data analysis in a group of focal drug-resistant epilepsy patients’ interictal spikes, we demonstrated the ability of FAST-IRES algorithm to image the location and extent of underlying epilepsy sources from MEG measurements. Our results indicate the merits of FAST-IRES in imaging the location and extent of epilepsy sources for pre-surgical evaluation from MEG measurements.