Effect of conductivity uncertainties on EEG source localization using a 2D finite element model

The authors present a sensitivity study of electroencephalography based source localization due to errors in tissue conductivities and to errors in modeling the conductivity variation inside the brain and scalp. The study is conducted using a 2D finite element model obtained from an MRI scan of a head cross-section. The effect of uncertainty in the following tissues are studied: white matter, grey matter, cerebrospinal fluid (CSF), skull, and fat. The distribution of source location errors, assuming a single-dipole source model is examined in detail for different dipole locations over the whole brain region. Results presented in this paper clearly point to the following conclusion. Unless the conductivities of the head tissues and the distribution of these tissues throughout the head are modeled accurately, the goal of achieving localization accuracy to within a few millimeters is unattainable.