Progression of logopenic variant primary progressive aphasia to apraxia and semantic memory deficits

Due to the nature of neurodegenerative disorders, patients with primary progressive aphasia develop cognitive impairment other than aphasia as the disorder progresses. The progression of logopenic variant primary progressive aphasia (lvPPA), however, has not been well described. In particular, praxic disorders and semantic memory deficits have rarely been reported. We report three patients in the initial stage of lvPPA who subsequently developed apraxia in the middle stage and developed clinically evident semantic memory deficits in the advanced stages. The present case series suggests that some patients with lvPPA develop an atypical type of dementia with apraxia and semantic memory deficits, suggesting that these cases should be classified as a type of early-onset Alzheimer's disease.