Interictal and ictal magnetoencephalographic study in patients with medial frontal lobe epilepsy.
OBJECTIVE
To determine whether magnetoencephalography (MEG) has any clinical value for the analysis of seizure discharges in patients with medial frontal lobe epilepsy (FLE).


METHODS
Four patients were studied with 74-channel MEG. Interictal and ictal electroencephalographic (EEG) and MEG recordings were obtained. The equivalent current dipoles (ECDs) of the MEG spikes were calculated.


RESULTS
In two patients with postural seizures, interictal EEG spikes occurred at Cz or Fz. The ECDs of interictal MEG spikes were localized around the supplementary motor area. In the other two patients with focal motor or oculomotor seizures, interictal EEG spikes occurred at Fz or Cz. The ECDs of interictal MEG spikes were localized at the top of the medial frontal region. The ECDs detected at MEG ictal onset were also localized in the same area as those of the interictal discharges.


CONCLUSIONS
In medial FLE patients, interictal and ictal MEG indicated consistent ECD localization that corresponded to the semiology of clinical seizures. Our findings demonstrate that MEG is a useful tool for detecting epileptogenic focus.
Shiraishi
H
H
National Epilepsy Center, Shizuoka Higashi Hospital, Shizuoka, Japan. shiraishi@nmr.mgh.harvard.edu
Watanabe
Y
Y
Watanabe
M
M
Inoue
Y
Y
Fujiwara
T
T
Yagi
K
K
D000293:Adolescent; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000503:physiopathology; D002675:Child, Preschool; D004569:Electroencephalography / Q000706:statistics & numerical data; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male