EEG has diagnostic partner in MEG

To better understand how the brain's magnetic field might be used in medical diagnosis, scientists at the Massachusetts Institute of Technology (MIT), Cambridge, have produced simultaneous magnetoencephalogram (MEG) and electroencephalogram (EEG) maps of two human heads. A comparison of the two volunteers' brain mappings demonstrates the differences between the EEG, which records the electrical potential on the scalp, and the MEG, which records the magnetic field produced by the same electrical activity. The MEG seems to be most useful when it complements information provided by the EEG; by itself it does not pinpoint electrical activity much better than the EEG. According to physicist David Cohen, PhD, and electrical engineer B. Neil Cuffin, PhD, there are several major differences between the two types of signals (Electroencephalogr Clin Neurophysiol1983; 56:38-51). The first is that, although both the EEG and the MEG result from the same electrical activity in the brain, the