Topographic distribution of the periodic discharges in Creutzfeldt-Jakob disease (CJD)

A characteristic EEG abnormality in patients with Creutzfeldt-Jakob disease (CJD) consists of periodic high voltage bilateral diphasic or triphasic sharp waves widely distributed over both hemispheres. The mechanism underlying these electrographic manifestations is, however, unclear. To increase our understanding of these phenomena, we have employed the technique of microcomputer brain mapping, to analyze the electrical fields of the bilaterally-distributed complexes in four patients with CJD. Ten generalized discharges were studied in each patient. The EEG analysis demonstrated variability in the area of onset as well as the field maxima between the different complexes among patients as well as between discharges in each patient. The generalized pattern seen in routine EEG was clearly shown on brain mapping to be not strictly generalized from onset, nor bilaterally symmetrical. These findings may suggest multifocal areas of onset of the generalized discharges, or alternating pathways of activation of the cortical areas by a subcortical pacemaker.