EEG Source Imaging in Partial Epilepsy in Comparison with Presurgical Evaluation and Magnetoencephalography.
OBJECTIVE
The aim of this study was to determine the usefulness of three-dimensional (3D) scalp EEG source imaging (ESI) in partial epilepsy in comparison with the results of presurgical evaluation, magnetoencephalography (MEG), and electrocorticography (ECoG).


METHODS
The epilepsy syndrome of 27 partial epilepsy patients was determined by presurgical evaluations. EEG recordings were made using 70 scalp electrodes, and the 3D coordinates of the electrodes were digitized. ESI images of individual and averaged spikes were analyzed by Curry software with a boundary element method. MEG and ECoG were performed in 23 and 9 patients, respectively.


RESULTS
ESI and MEG source imaging (MSI) results were well concordant with the results of presurgical evaluations (in 96.3% and 100% cases for ESI and MSI, respectively) at the lobar level. However, there were no spikes in the MEG recordings of three patients. The ESI results were well concordant with MSI results in 90.0% of cases. Compared to ECoG, the ESI results tended to be localized deeper than the cortex, whereas the MSI results were generally localized on the cortical surface. ESI was well concordant with ECoG in 8 of 9 (88.9%) cases, and MSI was also well concordant with ECoG in 4 of 5 (80.0%) cases. The EEG single dipoles in one patient with mesial temporal lobe epilepsy were tightly clustered with the averaged dipole when a 3 Hz high-pass filter was used.


CONCLUSIONS
The ESI results were well concordant with the results of the presurgical evaluation, MSI, and ECoG. The ESI analysis was found to be useful for localizing the seizure focus and is recommended for the presurgical evaluation of intractable epilepsy patients.
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.|Samsung Biomedical Research Institute (SBRI), Seoul, Korea.
Chae Jung
CJ
Park
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Ji Hye
JH
Seo
Department of Neurology, Chungnam National University School of Medicine, Daejeon, Korea.
Daeyoung
D
Kim
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.|Department of Electrical & Computer Engineering, University of Houston, Houston, TX, USA.
Berdakh
B
Abibullaev
Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.
Hyukchan
H
Kwon
Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.
Yong Ho
YH
Lee
Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.
Min Young
MY
Kim
Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.|Department of Medical Physics, University of Science and Technology, Daejeon, Korea.
Kyung Min
KM
An
Center for Biosignals, Korea Research Institute of Standards and Science, Daejeon, Korea.|Department of Medical Physics, University of Science and Technology, Daejeon, Korea.
Kiwoong
K
Kim
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Jeong Sik
JS
Kim
Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Eun Yeon
EY
Joo
Samsung Biomedical Research Institute (SBRI), Seoul, Korea.|Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea. sbhong@skku.edu.
Seung Bong
SB
Hong
EEG source imaging; MEG source imaging; epilepsy surgery; partial epilepsy; presurgical evaluation; source localization