The influence of electrode location errors on EEG dipole source localization with a realistic head model

Objectives: Inaccurate information about the electrode locations on the scalp will introduce errors in electroencephalogram dipole source localization results. The present study uses computer simulations to evaluate such errors in a realistic head model and in the context of noise. Methods: A realistic head model was constructed from magnetic resonance imaging scans and 29 electrodes placed on the head according to the 10-20 International System. Twenty sets of electrode displacements, with a mean, value of 5 mm, were generated and 200 single dipoles evenly located in the brain were used as test sources. The boundary element method was employed for the froward calculation and dipole fitting was carried out at different noise levels. Results: For a noise-free signal, the source localization error due to electrode misplacement is about 5 mm, whereas it is about 2 mm for normal noisy signals. Conclusions: For realistic head models, dipole estimation error due to electrode misplacement is negligible compared with errors caused by noise. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.