The Progressive Acalculia Presentation of Parietal Variant Alzheimer's Disease.

Background: Many patients with early-onset Alzheimer's disease (EOAD; age of onset <65 years) have non-amnestic presentations involving language (logopenic primary progressive aphasia, lvPPA), visuospatial abilities (posterior cortical atrophy, PCA), and even asymmetric symptoms consistent with corticobasal syndrome (CBS). An inferior parietal lobule variant of EOAD commonly presents with progressive difficulty with calculations.

Methods: We reviewed 276 EOAD patients for presentations with predominant acalculia.