EEG-fMRI study of the interictal epileptic activity in patients with partial epilepsy.
OBJECTIVE
To investigate Blood Oxygen Level Dependent (BOLD) responses to interictal epileptic discharges (IEDs) during EEG-correlated functional MRI (EEG-fMRI) in patients with partial epilepsy.


METHODS
We studied eight patients who had a diagnosis of partial epilepsy and active spiking on routine scalp EEG recording. Sessions of continuous EEG-fMRI were recorded, and spikes (identified after online artifact removal) were used as events in the fMRI analysis. Regions of BOLD signal change in response to interictal epileptic discharge were assessed and epileptogenic zone localization was electroclinically identified.


RESULTS
Eight patients with partial epilepsy were recruited (6 males, 2 females, mean age 18.5, mean onset age range 0.5-29). Two who underwent EEG-fMRI were excluded from further analysis: one due to absence of epileptic discharges, the other due to excessive head motion. Eight sessions of EEG-fMRI scanning in 6 patients were obtained: 6 with activation and deactivation, one with activation only, and one with deactivation only. Focal activations corresponding to electroclinical localization occurred in 7 sessions, 5 of which were maximal.


CONCLUSIONS
Maximally activated areas detected by EEG-fMRI in patients with partial epilepsy appear to be concordant with epileptogenic areas as defined by electroclinical localization data. In most patients with focal epilepsy, positive BOLD responses seem to be mainly in epileptogenic zones and the corresponding contralateral areas. Responses to deactivation seem less associated with IEDs. So EEG-fMRI is a useful tool to study the pathophysiological mechanisms of epilepsy and may assist in presurgical evaluation of epilepsy.
Liu
Yonghong
Y
Department of Neurology, West China Hospital, Si Chuan University, Chengdu, Sichuan, P. R. China.
Yang
Tianhua
T
Yang
Xuhong
X
Liu
Iing
I
Liao
Wei
W
Lui
Su
S
Huang
Xiaoqi
X
Chen
Huafu
H
Gong
Qiyong
Q
Zhou
Dong
D
D000293:Adolescent; D000328:Adult; D002540:Cerebral Cortex / Q000098:blood supply* / Q000503:physiopathology*; D002648:Child; D004569:Electroencephalography; D004828:Epilepsies, Partial / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010100:Oxygen / Q000097:blood
D010100:Oxygen