Clinical Manifestations

Background: Primary Progressive Aphasia (PPA) is a neurodegenerative disorder primarily affecting language abilities, with clinical variants (nonfluent/agrammatic variant [nfvPPA], semantic variant [svPPA], logopenic variant [lvPPA], and mixed-PPA [mPPA]) categorized based on linguistic features. This study aims to compare PPA cohorts of native speakers of two different languages: English (an analytic language with deep orthography) and Italian (a synthetic language with shallow orthography).

Methods: We considered 166 English participants (70 nfvPPA, 45 svPPA, 42 lvPPA, 9 mPPA) and 106 Italian participants (14 nfvPPA, 20 svPPA, 42 lvPPA, 31 mPPA). Starting from the neuropsychological battery used to assess patients, we extracted one test for each cognitive and linguistic function that can be compared between cohorts. Comparisons were adjusted for symptom duration and Mini-mental State Examination scores.

Results: The English cohort included a higher proportion of nfvPPA patients (42% vs. 13%, p<0.001), while the Italian cohort showed higher proportions of lvPPA (25% vs. 38%, p = 0.019) and mPPA (5% vs. 29%, p<0.001). English nfvPPA patients were more frequently impaired in single-word comprehension (60% vs. 8%, p = 0.013), while Italian nfvPPA patients exhibited more agrammatism (46% vs. 93%, p = 0.015). English svPPA had a higher proportion of surface dyslexia (68% vs. 30%, p = 0.046) and spelling impairment (38% vs. 10%, p = 0.021). English lvPPA had broader impairments, including single-word comprehension (89% vs. 29%, p<0.001), repetition of words (61% vs. 26%, p = 0.03), nonverbal working memory (69% vs. 36%, p = 0.005), and visuospatial perception (89% vs. 25%, p<0.001).

Conclusions: This study reveals linguistic and cognitive distinctions between English and Italian PPA cohorts, emphasizing the impact of language-specific characteristics on symptomatology. Cultural and linguistic nuances should be considered in PPA diagnosis and management, calling for more tailored assessments and criteria.