White Paper: Electromagnetic Simulation Aids Development Of Unique EEG Cap

Researchers at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital (MGH), Charlestown, Massachusetts, are developing a special electroencephalography (EEG) cap for use with a research technique that integrates EEG with magnetic resonance imaging (MRI). This integrated technique offers the potential to improve investigations of brain activity. But the RF generated by MRI induces currents in the EEG electrodes. Concerns have arisen that this current could generate temperature increases in sensitive brain tissues. The researchers recognized that they would have to evaluate many different electrode types and arrangements in order to optimize the design of the cap. These experiments obviously cannot be performed on human volunteers. It would be expensive to build a physical model with properties close to a human head. On the other hand, virtual models can be developed with properties very similar to a human head and used to predict the RF fields and tissue exposure to RF. But virtual models cannot be used with confidence to predict the performance of various types of electrodes and leads until they have been verified by physical experiments. It is very expensive to build a matching physical model to verify the accuracy of such a virtual model.