Primary Progressive Aphasia (PPA) is split into three archetypal subtypes, each of which is defined by a single aphasia symptom. Although other cognitive, behavioural, and motor domains may become engaged later in their course, little is known about each subtype's progression profile in relation to the other subtypes. 24 patients diagnosed with Semantic Variant (svPPA), 22 with non-fluent variant (nfvPPA), and 18 with Logopenic Variant (lvPPA) were collected and followed up for 1-6 years in this longitudinal retrospective cohort study based on new biomarker-supported diagnostic criteria. The severity of symptoms, scores on cognitive tests and neuropsychiatric inventories, and development into another syndrome were all evaluated. Over time, lvPPA developed broader language issues (PPA-extended) and nfvPPA developed mutism, although semantic impairment remained the primary issue in svPPA. Aside from linguistic issues, svPPA acquired significant behavioural issues, whereas lvPPA showed a higher deterioration in cognition. Motor impairments were more prevalent in the nfvPPA group. Furthermore, 65.6% of individuals met the clinical criteria for another neurodegenerative condition within 5 years of their clinical beginning (PPA-plus). The clinical features of 14 out of 24 (58%) svPPA patients were consistent with behavioural variant frontotemporal dementia, whereas 15/18 (83%) lvPPA patients were consistent with Alzheimer disease dementia. In addition, 12/22 (54%) of the nfvPPA patients advanced to satisfy the diagnostic criteria for corticobasal syndrome and progressive supranuclear palsy. Despite the fact that aphasia is the syndrome's initial and distinguishing feature, our longitudinal findings revealed that PPA is not a language-specific disorder, and that each subtype's course differs significantly in terms of symptom nature and disease duration.
