Abstract
Neuropathologic change underlying primary progressive aphasia (PPA) most commonly includes one of the frontotemporal lobar degenerations, such as FTLD-tau or FTLD-ubiquitin. The next most frequent etiology of PPA is Alzheimer's disease (AD). We describe 5 subjects with clinical diagnoses of semantic dementia, who underwent longitudinal clinical evaluation and postmortem neuropathology examination of the central nervous system. This case series examines retrospectively which clinical parameters might have pointed to the neuropathological diagnosis of AD. CONCLUSION: family history of late onset dementia, APOEepsilon4 status, combined features of semantic dementia and progressive non-fluent aphasia present early in illness, or generalized seizures, may indicate AD as the underlying pathology of semantic dementia.