From slowly progressive amnesic syndrome to rapidly progressive Alzheimer disease

A 57-year-old woman had a neuropsychologically documented 5-year history of a slowly progressive amnesic syndrome followed by a 1-year history of rapi dly progressive dementia. There was no family history of dementia. Magnetic resonance imaging failed to show a structural basis, electroencephalograph y failed to show changes of Creutzfeldt-Jakob disease, and cerebrospinal fl uid examination was normal. A diagnosis of Alzheimer disease was confirmed by brain biopsy. The abrupt change in disease course Nas unique but suggest ed probable overlap between posited subtypes of Alzheimer disease.