At present, in epilepsy, magnetoencephalography (MEG) is mostly used for presurgical evaluations. It has proven to be robust for detecting and localizing interictal epileptiform discharges. Whether this is also true for first-line investigation in the diagnosis of epilepsy has not been investigated yet. We present our data on the usefulness of MEG in the earliest phase of diagnosing epilepsy. We examined 51 patients with suspicion of neocortical epilepsy and an inconclusive routine EEG. A method to integrate MEG in daily routine was developed. Results of visually assessed MEG recordings were compared, retrospectively, with clinical data and with the results of EEG after sleep deprivation. After a finding of inconclusive, routine MEG generated a gain in diagnostic value of 63% when compared with “final” clinical diagnosis. This is comparable with the added value of EEG after sleep deprivation recorded previously in the same patients. However, MEG is less of a burden for patient and hospital and has no association with risk of increase in seizure frequency. The routine MEG with visual assessment only is a reliable diagnostic tool in the routine diagnosis of epilepsy and may replace or precede EEG after sleep deprivation in daily clinical practice. Furthermore, MEG together with MRI enables magnetic source imaging and, thus, may provide additional information on the cortical localization of the epilepsy of a patient.
From the Departments of *Clinical Neurophysiology, †Clinical Physics, Epilepsy centre Kempenhaeghe, Heeze, The Netherlands; ‡AZ Maria Middelares, Department of Neurology, Ghent, Belgium; §Department of Clinical Neurophysiology, VUmc, Amsterdam, The Netherlands; ∥Department of R&D, Epilepsy Centre Kempenhaeghe, Heeze, The Netherlands and ¶Department of Neurology, Ghent University Hospital, Belgium.
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None of the authors has any conflict of interest to disclose.
Address correspondence and reprint requests to A. J. Colon, M.D., Epilepsy Centre Kempenhaeghe, Sterkselseweg 65, P.O. Box 61, 5590AB Heeze, The Netherlands; e-mail: email@example.com.