Magnetoencephalography.

Magnetoencephalography (MEG) is the recording of magnetic fields generated by the brain. Since 1968, when the first observations of alpha rhythm were made, there have been occasional reports of neuromagnetic measurement. It was not until a few years ago, however, that a rather abrupt explosion of neuromagnetic investigation occurred. Most work has been done in the area of evoked magnetic responses. Magnetic measurement of spontaneous cerebral activity has been scanty, but the recent application of MEG for localizing epileptic foci has brought about renewed interest in the method. The claim that MEG can provide three-dimensional information suggests that this technique may replace depth recording. It has not been proved, however, that MEG is superior to EEG in localizing a current source. Whether MEG will supplement or replace EEG is still an open question. Because its usefulness is yet to be demonstrated realistically, continuous endeavor in this field is appropriate.