Creutzfeldt-Jakob disease presenting as isolated aphasia.

Progressive aphasia without dementia (primary progressive aphasia) is increasingly recognized as an important neurobehavioral syndrome. Clinical diagnosis of progressive aphasia is difficult early in its course, and the differential diagnosis is usually said to include Alzheimer's and Pick's diseases. We report a 61-year-old man with autopsy-proven Creutzfeldt-Jakob disease (CJD) whose major initial manifestation was a progressive, fluent aphasia. Myoclonus was absent, and characteristic EEG abnormalities appeared relatively late. We believe that this case of CJD is unique in its presentation of profound and isolated aphasia. CJD should be considered in the differential diagnosis of the progressive aphasia syndrome.