Sensitivity analysis to epileptic sources in Electro- and magnetoencephalography: A simulation approach

Electroencephalography (EEG) and magnetoencephalography (MEG) non-invasively record human neuronal activity. We aimed to evaluate the influence of source orientation and depth location on the detectability of epileptic spikes in simulated EEG and MEG data for varying levels of background activity. Our realistic three compartment boundary element method models and triangular grids of the convoluted cortical surfaces provided the simulation basis for EEG and MEG signals. Spike dipoles and background sources were quantitatively characterized by depth and orientation properties. We found that spike detectability in EEG signals decreased with increased radial and tangential background activity. SNR in MEG decreased only with increased tangential background activity. Simultaneous application of EEG and MEG improves the probability of spike detection.