Assessing Strengths and Limitations of Magnetoencephalography Source Imaging With Intracerebral EEG

Auteurs

Afnan J, Fratello M, Bonini F, Medina Villalon S, Cai Z, Lina JM, Badier JM, Bartolomei F, Gotman J, Bénar CG, Grova C

Les auteurs en lien sont membres de l'INS.

Équipes

DynaMap

Résumé

ABSTRACT Due to the ill‐posed nature of source imaging, EEG/MEG source localization remains challenging, particularly for localizing deep brain activity and resting‐state signals with low signal‐to‐noise ratios. Functional connectivity estimated by EEG/MEG is further affected by source‐leakage, a spatial blurring effect that complicates interpretation. Validation is therefore essential before applying EEG/MEG source imaging in clinical contexts. Using simultaneous MEG and stereotactic EEG (SEEG) recordings from patients with focal epilepsy, we present a comprehensive validation of MEG source imaging of epileptic discharges, resting‐state oscillations, and connectivity. Virtual SEEG was computed from MEG source maps to enable direct quantitative comparison with in situ SEEG. Using the Maximum Entropy on the Mean method, MEG localized the generators of epileptic spikes with a median error of 15 ± 12 mm, with deep generators showing larger errors. MEG‐derived resting‐state power showed significant spatial correlations with SEEG, with frequency‐specific correspondence, stronger in the alpha and beta bands than in the theta band. MEG functional connectomes estimated using leakage‐correc

ABSTRACT Due to the ill‐posed nature of source imaging, EEG/MEG source localization remains challenging, particularly for localizing deep brain activity and resting‐state signals with low signal‐to‐noise ratios. Functional connectivity estimated by EEG/MEG is further affected by source‐leakage, a spatial blurring effect that complicates interpretation. Validation is therefore essential before applying EEG/MEG source imaging in clinical contexts. Using simultaneous MEG and stereotactic EEG (SEEG) recordings from patients with focal epilepsy, we present a comprehensive validation of MEG source imaging of epileptic discharges, resting‐state oscillations, and connectivity. Virtual SEEG was computed from MEG source maps to enable direct quantitative comparison with in situ SEEG. Using the Maximum Entropy on the Mean method, MEG localized the generators of epileptic spikes with a median error of 15 ± 12 mm, with deep generators showing larger errors. MEG‐derived resting‐state power showed significant spatial correlations with SEEG, with frequency‐specific correspondence, stronger in the alpha and beta bands than in the theta band. MEG functional connectomes estimated using leakage‐correc

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