Imaging foci of epileptic discharges from simultaneous EEG and fMRI using the canonical HRF.
OBJECTIVE
Simultaneous electroencephalography and functional magnetic resonance imaging (EEG-fMRI) is considered as a powerful and non-invasive method that allows definition of the irritative zone. However, the complex interictal epileptic discharge (IED) may be present in some patients, and sometimes no active foci can be localized using General Linear Model (GLM) which is a widely adopted tool in EEG-fMRI study. The purpose of this study is to develop a new scheme to improve the detectability and localize the canonical HRF localizable foci.


METHODS
Various IEDs are classified using a combination of an independent component analysis (ICA) and a temporal correlation analysis between the independent components and the raw EEG channel; and the classified IEDs are then separately used for foci localization. This scheme is tested by ten patients with variable IEDs, including two patients whose activity could not be identified by common method.


RESULTS
Applying this scheme to the two patients, some foci consistent with electroclinical data were localized. When it was applied to the remaining eight patients with positive results using common method, 2-4 types of IEDs were classified, and the activity could be identified from at least one type of IED. The results were similar to that received from common method.


CONCLUSIONS
These results indicate that the proposed scheme could enhance the imaging of the localizable foci by isolating its IEDs. This scheme is potentially a useful tool for epilepsy clinic.
Luo
Cheng
C
Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.
Yao
Zhiping
Z
Li
Qifu
Q
Lei
Xu
X
Zhou
Dong
D
Qin
Yun
Y
Xia
Yang
Y
Lai
Yongxiu
Y
Gong
Qiyong
Q
Yao
Dezhong
D
D000293:Adolescent; D002648:Child; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D055815:Young Adult