Magnetoencephalography (MEG) Augments Semiology in Stereotactic Electroencephalography (SEEG) Evaluations

The foundation of a successful stereotactic electroencephalography (SEEG) evaluation has remained relatively unchanged since the first SEEG implantation in 1957 and is predicated on a robust semiology-driven hypothesis. Although epilepsy presurgical evaluation has expanded since the 1950s with the introduction of new technology, e.g., brain magnetic resonance imaging (MRI), few, if any, noninvasive diagnostic studies provide significant complementary information to the epilepsy presurgical evaluation as magnetoencephalography (MEG). As SEEG becomes increasingly ubiquitous as the intracranial EEG modality of choice for more comprehensive epilepsy centers, the importance of MEG in the epilepsy presurgical evaluation also increases. In this review, the use of MEG in addition to seizure semiology in the development of an SEEG implantation strategy will be reviewed and illustrated with two representative cases. Finally, within this review, epilepsy surgical outcomes from presurgical evaluations that incorporated MEG will be discussed.