Error bounds for MEG and EEG source localization

Localization error bounds are presented for both electroencephalograms (EEGs) and magnetoencephalograms (MEGs) as graphical error contours for a 37-sensor arrangement. Both one and two dipole cases were examined for all possible dipole orientations and locations within a head quadrant. The results show a strong dependence on absolute dipole location and orientation. The results also show that fusion of the EEG and MEG measurements into a combined model reduces the lower bound. A Monte Carlo simulation was performed to check the tightness of the bounds for a selected case. The simple head model, the white and relatively low power noise, and the few relatively strong dipoles were all selected in this study as optimistic conditions to establish possibly fundamental resolution limits for any localization effort