Primary Progressive Aphasia: Neuropsychological Aspects of Language Impairments in Monolingual and Bilingual Individuals

Primary Progressive Aphasia (PPA) emerges as a unique clinical syndrome primarily characterized by language impairments, captivating researchers and clinicians alike. Manifesting between the ages of 60 to 65, PPA's initial symptoms intricately involve speech and language difficulties, encompassing challenges in language production, object naming, syntax, and word comprehension. As the syndrome progresses, additional cognitive deficits beyond language surface, with three distinct variants—nonfluent PPA (nfvPPA), semantic variant PPA (svPPA), and logopenic variant PPA (LPA)—contributing to its clinical complexity. To navigate the heterogeneous pathology of PPA, understanding its underlying neurodegenerative processes is paramount. Biomarkers and genetics serve as essential avenues, providing neurologists with insights into the diverse clinical manifestations. The exploration of PPA extends beyond linguistic complexities, revealing profound connections to genetic and biomolecular frameworks. Insights into the trio of PPA variants highlight the diverse genetic influences shaping its manifestation, emphasizing the importance of genetic codes and biomarker signatures in precise diagnosis and guiding future therapeutic strategies. Additionally, the thesis delves into the protective benefits of bilingualism against age-related cognitive decline, unveiling cognitive resilience and delayed onset of Alzheimer's symptoms in bilingual individuals. Neuroimaging studies further illuminate distinct activation patterns in the aging brains of bilinguals, emphasizing the role of linguistic factors in cognitive health. Language assessments emerge as critical tools, tailored to address the challenges posed by PPA in both monolingual and bilingual patients. Establishing the indispensable role of meticulously designed tools for bilingual individuals, the thesis paves the way for potential treatments and therapies, including neuromodulation techniques and speech theory. In conclusion, this comprehensive exploration lays the groundwork for a nuanced understanding of PPA, spanning from its linguistic challenges to additional cognitive deficits, and elucidating the role of biomarkers, genetics, bilingualism, and language assessments. The thesis contributes to informed clinical interventions and sets the stage for future research in addressing the complex challenges posed by PPA.