RESUMEN
A few autopsy proved cases of Alzheimer's disease with myoclonus have been hitherto reported. We think that myoclonus is a frequent clinical feature in advanced cases of Alzheimer's disease. Our second case is such an example with a chronic evolution. In cases like our first one, with a short history, myoclonus, and atypical, diphasic, periodic complexes in the EEG, clinical differential diagnosis with Creutzfeldt-Jakob disease can be very difficult. Alzheimer disease has been considered an unitary clinico-pathological entity. However, transmission to the non human primates has been successfully achieved only in familiar cases but no in the sporadic ones. On the other hand some of his neuropathological features have been found in two cases of Creutzfeldt-Jakob disease, one of them successfully transmitted to the chimpanzee. All these points could eventually modify our present unitary concept on Alzheimer's disease.