Can dipole modelling be improved by removing muscular and ocular artifacts from ictal scalp EEG?

Muscle artifacts and eye movement artifacts distort the EEG and make EEG dipole source localization near the ictal onset of the seizure very difficult and unreliable. Recently, two algorithms to remove these artifacts have been developed and validated. In our study we want to investigate if the multiple dipole model can be used in ictal EEG source localization. Furthermore, we want to investigate whether the use of the dipole model returns better interpretable results when artifacts are suppressed. The EEG dipole source localization was done by using the RAP-MUSIC algorithm. We used the relative residual energy as a goodness of fit for the dipole model. We found that in the unfiltered EEG the relative residual energy was very high, indicating that EEG dipole source localization is heavily affected by the noise. By removing the artifacts, we obtain a lower relative residual energy, which suggests that the multiple dipole model becomes an adequate model for EEG dipole source localization during ictal period.