The need for correct realistic geometry in the inverse EEG problem

For accurate electroencephalogram-based localization of mesial temporal and frontal sources correct modeling of skull shape and thickness is required. In a simulation study in which results for matched sets of computed tomogr aphy and magnetic resonance (MR) images are compared, it is found that erro rs arising from skull models based on smooth and inflated segmented MR imag es of the cortex are of the order of I cm, These errors are comparable to t hose found when overestimating or underestimating skull conductivity by a f actor of two.