Disappearance of periodic sharp wave complexes in Creutzfeldt-Jakob disease.

Periodic sharp wave complexes (PSWC) are sensitive and specific of Creutzfeldt-Jakob disease (CJD). Once they have emerged, PSWC may exceptionally disappear in the terminal stage of the disease, as a consequence of the flattening of scalp electroencephalogram (EEG). We document the disappearance of PSWC in serial EEG during the clinical course in two women (57 and 70 years of age) with pathologically proven CJD. Despite PSWC disappearance, diffuse theta-delta activity was still well recognizable. Moreover, external stimuli failed to trigger PSWC. The absence of PSWC in CJD might be due to the timing and frequency of EEG recordings. PSWC disappearance should not be interpretated as evidence against the diagnosis of CJD.