An example of the possible clinical usefulness of topographic EEG displays

This paper shows the brain maps of a patient before and during a seizure initiated by a focus within the right occipital area. The maps demonstrate an ictal transformation in the form of a gradual decrease in frequency of the ictal rhythms, seen also on the EEG traces. However, the maps also show the very distinct difference in the background activity between the left and right hemispheres, and also the possibility of independent foci of depressed activity within the right anterior and posterior temporal areas, the latter not at all evident on the EEG tracings. This case may serve as an example of useful data gathered on a patient by EEG topography, not made clear by a standard recording.