NONINVASIVE EPILEPTIC FOCUS LOCALIZATION USING EEG-TRIGGERED FUNCTIONAL MRI AND ELECTROMAGNETIC TOMOGRAPHY

We present a new approach for non-invasive localization of focal epile ptogenic discharges in patients considered for surgical treatment. EEG -triggered functional MR imaging (fMRI) and 3D EEG source localization were combined to map the primary electrical source with high spatial resolution. The method is illustrated by the case of a patient with me dically intractable frontal lobe epilepsy. EEG obtained in the MRI sys tem allowed triggering of the fMRI acquisition by the patient's habitu al epileptogenic discharges. fMRI revealed multiple areas of signal en hancement. Three-dimensional EEG source localization identified the sa me active areas and provided evidence of onset in the left frontal lob e. Subsequent electrocorticography from subdural electrodes confirmed spike and seizure onset over this region. This approach, i.e. the comb ination of EEG-triggered fMRI and 3D EEG source analysis, represents a promising additional tool for presurgical epilepsy evaluation allowin g precise non-invasive identification of the epileptic foci. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.