The influence of electrode location errors on EEG dipole source localization with a realistic head model.
OBJECTIVE
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 forward 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.
Wang
Y
Y
The Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, Quebec, Canada H3A 2B4.
Gotman
J
J
D016477:Artifacts; D001921:Brain / Q000502:physiology*; D003198:Computer Simulation; D004566:Electrodes / Q000009:adverse effects*; D004569:Electroencephalography / Q000295:instrumentation* / Q000592:standards*; D006257:Head / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008953:Models, Anatomic; D012535:Scalp / Q000502:physiology