Specific electroencephalogram features in the very early phases of sporadic Creutzfeldt–Jakob disease

Abstract

Studies on the very early electroencephalography (EEG) features prior to the emergence of generalized periodic discharges (GPDs, generally known as periodic sharp-wave complexes) in Creutzfeldt–Jakob disease (CJD) are rare. Fourteen patients with sporadic CJD (sCJD) (eight with MM1/classic and six with MM2c) were included in this study. The predominant findings of the first EEG were categorized as 1) lateralized periodic discharges (LPDs), 2) central sagittal sporadic epileptiform discharges (CSSEDs) showing midline predominant generalized spike-and-wave complexes and/or sharp waves in the central sagittal regions, or 3) focal epileptiform discharges. Clinical records, magnetic resonance imaging (MRI), and changes in EEG were compared between three groups (LPD in MM1/classic, CSSED in MM1/classic, and focal epileptiform discharge in MM2c). Three (37.5%) and five (62.5%) patients with MM1/classic sCJD were classified into the LPD and CSSED groups, respectively. Patients in the LPD group were accompanied by cortical hyperintensities at the corresponding areas on MRI, while those in the CSSED group showed hyperintensities on MRI at unassociated cortical areas. Follow-up EEG of three (100%) patients in the LPD group and four (80%) in the CSSED group showed transitions to GPDs. All patients with MM1/classic sCJD showed myoclonus on initial EEG, and the symptomatic side was opposite to the hemisphere showing LPDs or higher-amplitude central sagittal epileptiform activity. The periodicity after these EEGs likely contributes to the diagnostic confidence of physicians when patients are in the very early stages of MM1/classic sCJD.