Magnetoencephalographic and electroencephalographic source localization of the interictal spike activities in patients with medial temporal lobe epilepsy

摘要

Magnetoencephalographic (MEG) and electroencephalographic (EEG) source localization of the interictal spike activities was performed in 5 patients with medial temporal lobe epilepsy (MTLE) to clarify the usefulness of MEG as the preoperative noninvasive examination. According to the Ebersole's classification based on the pattern of spike source localization and orientation, three patients were classified to posterior temporal vertical type, one anterior temporal horizontal type, and one anterior temporal vertical type. In all cases, the MEG and EEG spike did not completely coincide in waveform with each other. The latency of the best correlated equivalent current dipole (ECD) with MEG was slightly shorter than the peak latency of EEG spike. Although the EEG-source montage images at this latency were failed to reveal the potential to be localized to the medial temporal lobe, they demonstrated the potential to extend to the lateral temporal lobe at the peak latency of EEG spike. All patients became seizure free following anterior temporal lobectomy with hippocampectomy. The MEG spike source localization based on the Ebersole's classification may be calculated by the potential extended to the lateral temporal lobe, and, thus, was not useful in the diagnosis of MTLE and for predicting postoperative seizure outcome.