Primary Tauopathy With Logopenic/Semantic Mixed Progressive Aphasia and Frontotemporal Dementia-like Behavior

Here we present the cases of two individuals with language and behavioral symptoms indicative of the early clinical manifestations of both Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD). Phonological language symptoms similar to those evident in logopenic variant primary progressive aphasia suggested AD pathology, while semantic impairment and behavioral changes (ie, abnormal eating behavior and disinhibition) suggested a diagnosis of FTLD. Multimodal neuroimaging studies revealed underlying neuropathology indicative of primary tauopathy with presumable 3/4-repeat isoform, devoid of amyloid deposition. We suggest that these cases may represent a previously unrecognized syndrome associated with non-Alzheimer primary tauopathy.