Atypical and typical presentations of Alzheimer's disease: a clinical, neuropsychological, neuroimaging and pathological study of 13 cases

There has been increasing awareness that some slowly progressive focal cort ical syndromes can be the presenting features of Alzheimer's disease, but p athological evidence has been sparse. This clinico-pathological series pres ents our experience with pathologically proven atypical as well as typical Alzheimer's disease presentations. We report and compare four patterns of p resentation: a typical pattern with initial amnesic syndrome (n = 4 cases), progressive visual dysfunction (n = 1), progressive biparietal syndrome (n = 2) and progressive aphasia (n = 6), The aphasic presentations include bo th fluent and non-fluent aphasic syndromes. The neuropsychological profiles and neuroimaging clearly reflect the presenting clinical features, and sho w a close relationship to the distribution of pathology in these cases. Of note was the sparing of medial temporal structures (hippocampus and/or ento rhinal cortex) in several aphasic cases and the severe occipito-parietal in volvement in those with prominent visuospatial disorders at presentation, O ur data demonstrate the wide spectrum of Alzheimer's disease presentations. The recognition of atypical presentations of Alzheimer's disease is import ant when attempting to make an early accurate pre-morbid diagnosis of neuro degenerative disease.