[New developments in clinical neurophysiology: magnetoencephalography. Contributions of magnetoencephalography to the study of epilepsy].
INTRODUCTION: Magnetoencephalography (MEG) is a novel neurophysiological technique based on the detection of the tiny cerebral magnetic fields generated by the intracellular electrical currents. DEVELOPMENT: It offers several theoretical advantages to electroencephalography, like the transparency of the skull and soft tissues to the magnetic signal and the sensitivity to tangential fields generated in the cerebral sulci. Both properties allow an easier and more accurate modelling of the intracerebral sources. Furthermore, both techniques are complementary. On the other hand, its cost is the most limiting factor for its routine implementation in clinical practice. MEG is fully integrated with neuroimaging giving rise to the term magnetic source imaging. Integration with other neuroimaging modalities such us functional magnetic resonance imaging constitutes one of the major developments for the future. CONCLUSION: In this review, we present an overview of the physiological basis and technical aspects of magnetoencephalography, its comparison with electroencephalography, and its increasing number of clinical applications in the study of the different epilepsy syndromes as well as its role in epilepsy surgery.