Functional capacity in Peruvian people with Alzheimer's disease and frontotemporal dementia.

INTRODUCTION: Functional impairment across degenerative dementias remains understudied in Latin American contexts. We aimed to assess total and item-level functional performance, determine specific instrumental activities, and identify differences in functional profiles between groups. METHODS: In this cross-sectional study, 1445 participants were classified according to the Pfeffer Functional Activities Questionnaire (PFAQ). Statistical comparisons were adjusted for age, sex, and education using linear regression residuals and corrected for multiple comparisons. RESULTS: Functional impairment increased progressively from normal cognition to dementia. Alzheimer's disease (AD) and frontotemporal dementia (FTD) groups showed significantly greater total PFAQ scores compared to controls and mild cognitive impairment (MCI). Distinct profiles of impairment emerged: AD was more associated with memory-dependent tasks, while FTD showed disproportionate deficits in executive and social activities. DISCUSSION: Functional abilities are differentially impacted in AD and FTD within the Peruvian population. Our findings highlight the importance of item-level functional evaluation to support early detection and subtype differentiation of dementia in underserved regions. HIGHLIGHTS: We characterized and compared functional abilities among Peruvian older adults with normal cognition and neurodegenerative disease in different stages. PFAQ scores were analyzed across dementia stages in a Peruvian population. Functional abilities were differentially impacted in Peruvian participants with AD compared to FTD. AD was more associated with memory-dependent tasks, while FTD showed disproportional deficits in executive and social activities.