摘要：Primary progressive aphasia (PPA) is a neurodegenerative disorder characterized by specific and gradual decline inlanguage function (Mesulam, 2001). Two subtypes of PPA are agrammatic (PPA-G) and semantic (PPA-S), the formercharacterized by deficits in fluency and morphosyntax, and the latter characterized by deficits in single-wordcomprehension and naming (Mesulam et al., 2009).
