[Association of Alzheimer's disease and Creutzfeldt-Jakob's disease (author's transl)].

Serial EEG studies and full neuropathological investigations (optic and electronic microscopy of biopsy and necropsy material) were carried out on two patients: 1. A 68-year-old man: development in two and a half months of Creutzfeldt-Jakob's disease signalled by early clinical and EEG changes and confirmed by associated spongiosis of the triad characteristic of Alzheimer's disease, which was unexpected in this case. 2. A 43-year-old man: first phase of four years of progressive deterioration, followed by an encephalopathic syndrome with myoclonus developing in twelve months. The serial EEG studies showed discontinuous periodic paroxystic activity from the start of the second phase of the disease, although the first biopsy still showed nothing but the signs of Alzheimer's disease. A fortnight later, a second biopsy revealed ultrastructural microspongiosis. Examination of necropsy material confirmed the extensive association of the characteristic images of the two processes. On the basis of these two case studies and some similar cases published in the literature, the authors discuss the possible etiological links between these two diseases and stress the importance of the EEG and cerebral biopsy for the purposes of differential diagnosis. (Acta neurol. belg., 1977, 77, 202-212).