Primary Progressive Aphasia Across Languages: Prevalence and Presentation of Phenotypes Are Shaped by Language-Specific Features

Primary progressive aphasia (PPA) comprises a diverse group of neurodegenerative disorders usually characterized by heterogeneity in the clinical presentation, neuropathologic features, and genetic linkages.¹ Current consensus diagnostic criteria for PPA recognize 3 canonical syndromic variants defined by different language and communication impairments2: nonfluent/agrammatic variant PPA (nfvPPA), semantic variant PPA (svPPA), and logopenic variant PPA (lvPPA). The current diagnostic criteria and our general understanding of PPA have largely been based on studies in native English speakers. However, accumulating evidence suggests that language-specific features influence PPA presentation, which has implications for the generalizability of current PPA diagnostic criteria and treatment guidelines.³.