Magnetoencephalography in patients with tuberous sclerosis and localization-related epilepsy.
OBJECTIVE
To clarify the usefulness of magnetoencephalography (MEG) for diagnosis of the spatial relations between spike foci and suspicious epileptogenic tubers on MRI in patients with tuberous sclerosis (TS) and to compare MEG spike foci with single-photon emission computed tomography (SPECT) findings.


METHODS
We analyzed magnetic fields of epileptic spike discharges in 15 patients with TS and localization-related epilepsy (LRE) by using MEG (a whole-head 204-channel magnetometer system). We investigated the spatial relation between the equivalent current dipoles (ECDs) of interictal spike discharges and visible cortical tubers on MRI. We also compared results of MEG and MRI with SPECT findings.


RESULTS
MEG detected a cluster of ECDs around one cortical tuber in six of 15 patients and clusters of ECDs around two cortical tubers in five patients. Interictal SPECT was disappointing in detection of epileptic foci in TS. However, MEG spike foci showed spatial consistency with ictal hyperperfusion areas in two patients. Three patients with single ECD clusters underwent surgical treatment: two have been seizure free, and one has obtained seizure reduction of >90%.


CONCLUSIONS
ECDs were located around visible tuber nodules. MEG enabled precise localization of the epileptic foci and provided crucial information for surgical treatment in patients with TS and partial epilepsy. TS patients showing a single ECD cluster on MEG may be appropriate candidates for surgical treatment.
Kamimura
Takanori
T
Department of Homeostatic Regulation and Development, Niigata Graduate School of Medical and Dental Sciences, and Department of Pediatric Neurology, Epilepsy Center, Nishi-Niigata Chuo National Hospital, Niigata, Japan.
Tohyama
Jun
J
Oishi
Makoto
M
Akasaka
Noriyuki
N
Kanazawa
Osamu
O
Sasagawa
Mutsuo
M
Kato
Mitsuhiro
M
Ohno
Kousaku
K
Masuda
Hiroshi
H
Kameyama
Shigeki
S
Uchiyama
Makoto
M
D000293:Adolescent; D000328:Adult; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D004828:Epilepsies, Partial / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D015225:Magnetoencephalography / Q000706:statistics & numerical data*; D008297:Male; D013702:Temporal Lobe / Q000503:physiopathology / Q000601:surgery; D015899:Tomography, Emission-Computed, Single-Photon / Q000706:statistics & numerical data; D014402:Tuberous Sclerosis / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery