Was this the video you watched? (A woman switches on command while undergoing an EEG)



Or this one? (Woman switches on command while undergoing MRI scan)



While EEGs and MRIs are not currently used to diagnose DID I think there is a LOT more research that can be done in this area. When it comes down to it mental disorders are biological disorders as well, and there will be a way to pinpoint what is happening on a neurological level in disorders like DID... even if science hasn't quite figured it out yet.

Two of the issues that are likely to be barriers adequate research are firstly in getting ethical consent, and secondly getting an adequate number of subjects for valid control based studies to be done.