THE INFLUENCE OF SKULL-CONDUCTIVITY MISSPECIFICATION ON INVERSE SOURCE LOCALIZATION IN REALISTICALLY SHAPED FINITE-ELEMENT HEAD MODELS

The electric conductivities of different tissues are important paramet ers of the head model and their precise knowledge appears to be a prer equisite for the localization of electric sources within the brain To estimate the error in source localization due to errors in assumed con ductivity values, parameter variations on skull conductivities are exa mined. The skull conductivity was varied in a wide range and, in a sec ond part of this paper, the effect of a nonhomogeneous skull conductiv ity was examined. An error in conductivity of lower than 20% appears t o be acceptable for fine finite element head models with average discr etization errors down to 3mm. Nonhomogeneous skull conductivities, e.g ., sutures, yield important mislocalizations especially in the vincint y of electrodes and should be modeled.