Cognitive reserve and longitudinal changes in brain and cognition in semantic variant primary progressive aphasia

INTRODUCTION: Cognitive reserve (CR) refers to the brain's ability to maintain cognitive performance despite neurodegeneration. Studying CR in semantic variant primary progressive aphasia (svPPA) may clarify variability in disease progression and identify protective factors. METHODS: We examined whether education and occupational attainment-two common CR proxies-moderated relationships between gray matter brain volume and cognitive performance in 58 individuals with svPPA. Multiple linear regression models assessed baseline and longitudinal change across five semantic and non-semantic tasks. RESULTS: Greater brain volume related to better cognitive performance across all tasks. However, CR moderated this relationship only for semantic tasks. At baseline, higher education/occupation was linked to better semantic performance when brain volume was lower. Longitudinally, higher education/occupation was associated with faster decline in semantic performance when brain volume was lower. DISCUSSION: CR influences language performance in svPPA, suggesting its effects are domain-specific and aligned with the progression pattern of this syndrome.