Magnetoencephalographic studies of focal epileptic activity in three patients with epilepsy suggestive of Lennox-Gastaut syndrome.
OBJECTIVE
To determine the electromagnetic sources of localized epileptic activities using magnetoencephalography (MEG) in three adult patients with epilepsy suggestive of Lennox-Gastaut syndrome (LGS).


METHODS
MEG and simultaneous electroencephalography (EEG) were recorded from three adult patients using a 204-channel, whole-head MEG system. Equivalent current dipoles (ECDs) were calculated for epileptic spikes on MEG according to the single dipole model.


RESULTS
In two patients, MEG showed epileptiform discharges restricted to the unilateral temporal area, corresponding to the EEG spikes. The ECDs calculated from these MEG spikes were clustered in the unilateral temporal lobe. In our third patient, MEG spikes appeared in the right centroparietal area; ECDs were located to the right parietal lobe.


CONCLUSIONS
The sources of epileptiform discharges that were detected in a restricted area were localized to specific parts of the brain cortex. Despite certain limitations (small number of patients; atypical late-onset epilepsy in one) our study suggests that MEG may prove to be a useful tool for investigating electromagnetic features of localized epileptic discharges in patients with LGS. Based on these preliminary results, further studies performed in patients with typical LGS features are justified.
Sakurai
Kotaro
K
Department of Psychiatry and Neurology, Hokkaido University School of Medicine, Sapporo, Japan. kootaroo@m2.dion.ne.jp
Tanaka
Naoaki
N
Kamada
Kyousuke
K
Takeuchi
Fumiya
F
Takeda
Youji
Y
Koyama
Tsukasa
T
D000328:Adult; D001931:Brain Mapping / Q000379:methods; D002540:Cerebral Cortex / Q000503:physiopathology*; D003937:Diagnosis, Differential; D004569:Electroencephalography / Q000706:statistics & numerical data; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000503:physiopathology; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000503:physiopathology; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male