Published for the American Association of Physicists in Medicine by the American Institute of Physics
Medical Physics vol:37 issue:8 pages:4475-4484
Purpose: Electroencephalogram EEG source analysis is a noninvasive technique used in the
presurgical of epilepsy. In this study, the dipole location and orientation errors due to skull conductivity
perturbations were investigated in two groups of three-dimensional head models: A spherical
head model and a realistic head model.
Methods: In each group, the head model had a brain-to-skull conductivity ratio R within the
range of 10–40. Solving the forward problem in the head model with skull conductivity perturbations
along with the inverse problem in the baseline head model with R=20 permitted the derivation
of the dipole estimation errors.
Results: Perturbations in the skull conductivity generated dipole location and orientation errors:
The larger the perturbations, the larger the errors and the error ranges. The dipole orientation error
due to skull conductivity perturbations was not great maximal mean of 5° in this study, but the
dipole location error was notable maximal mean of 5 mm.
Conclusions: Therefore, the influence of skull conductivity perturbations on EEG dipole source
analysis cannot be neglected. This study suggests that it is necessary to measure the skull conductivity
of the individual patients in order to achieve accurate EEG source analysis.