Diagnostic value of periodic complexes in Creutzfeldt-Jakob disease

In 1996, our group published objective electroencephalogram (EEG) criteria to define periodic sharp-wave complexes (PSWCs) suggestive for Creutzfeldt-jakob disease (CJD). These criteria have since then been strictly applied in all cases reported to us as possible CJD in the course of the German CJD surveillance study. Furthermore, EEG analysis of the records was performed without any additional information on complementary clinical and laboratory data. In this study, we investigated sensitivity, specificity, and the predictive values of these EEG criteria exclusively in cases in which autopsy confirmed (n = 150) or excluded (n = 56) CJD. EEG criteria were positive in 64% (n = 96) of the CJD cases and falsely positive in 9% (n = 5) of other dementias. The resulting figures for sensitivity, specificity, and positive and negative predictive values were 64%, 91%, 95%, and 49%, respectively. In the falsely positive cases, Alzheimer's disease (n = 4) and vascular dementia (n = 1) were the underlying diseases. However, only in one of these five cases both clinical and EEG data would have led to the false-positive result to diagnose probable CJD. These data prove the high diagnostic value of our objective EEG criteria in CJD.