Document Detail

Magnetoencephalography is more successful for screening and localizing frontal lobe epilepsy than electroencephalography.
MedLine Citation:
PMID:  17662061     Owner:  NLM     Status:  MEDLINE    
PURPOSE: The diagnosis of frontal lobe epilepsy may be compounded by poor electroclinical localization, due to distributed or rapidly propagating epileptiform activity. This study aimed at developing optimal procedures for localizing interictal epileptiform discharges (IEDs) of patients with localization related epilepsy in the frontal lobe. To this end the localization results obtained for magnetoencephalography (MEG) and electroencephalography (EEG) were compared systematically using automated analysis procedures. METHODS: Simultaneous recording of interictal EEG and MEG was successful for 18 out of the 24 patients studied. Visual inspection of these recordings revealed IEDs with varying morphology and topography. Cluster analysis was used to classify these discharges on the basis of their spatial distribution followed by equivalent dipole analysis of the cluster averages. The locations of the equivalent dipoles were compared with the location of the epileptogenic lesions of the patient or, if these were not visible at MRI with the location of the interictal onset zones identified by subdural electroencephalography. RESULTS: Generally IEDs were more abundantly in MEG than in the EEG recordings. Furthermore, the duration of the MEG spikes, measured from the onset till the spike maximum, was in most patients shorter than the EEG spikes. In most patients, distinct spike subpopulations were found with clearly different topographical field maps. Cluster analysis of MEG spikes followed by dipole localization was successful (n = 14) for twice as many patients as for EEG source analysis (n = 7), indicating that the localizability of interictal MEG is much better than of interictal EEG. CONCLUSIONS: The automated procedures developed in this study provide a fast screening method for identifying the distinct categories of spikes and the brain areas responsible for these spikes. The results show that MEG spike yield and localization is superior compared with EEG. This finding is of importance for the diagnosis and preoperative evaluation of patients with frontal lobe epilepsy.
Pauly Ossenblok; Jan C de Munck; Albert Colon; Willem Drolsbach; Paul Boon
Publication Detail:
Type:  Comparative Study; Evaluation Studies; Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-07-28
Journal Detail:
Title:  Epilepsia     Volume:  48     ISSN:  0013-9580     ISO Abbreviation:  Epilepsia     Publication Date:  2007 Nov 
Date Detail:
Created Date:  2007-11-16     Completed Date:  2008-01-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2983306R     Medline TA:  Epilepsia     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2139-49     Citation Subset:  IM    
Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands.
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MeSH Terms
Brain Mapping
Cluster Analysis
Electrodes, Implanted
Electroencephalography / methods*,  statistics & numerical data
Epilepsy, Frontal Lobe / diagnosis*,  physiopathology,  surgery
Frontal Lobe / physiopathology
Image Processing, Computer-Assisted
Magnetic Resonance Imaging / statistics & numerical data
Magnetoencephalography / methods*,  statistics & numerical data
Mass Screening / instrumentation,  methods
Middle Aged
Preoperative Care
Subdural Space

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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