A Longitudinal Analysis of Frontotemporal Dementia Patients in Spain Throughout the COVID-19 Pandemic: A Descriptive Study

BACKGROUND: Frontotemporal dementia (FTD) comprises a heterogeneous group of neurodegenerative syndromes with variable behavioral, cognitive, and language profiles. Longitudinal data describing its clinical course using FTD-specific instruments remain scarce. This study aimed to characterize the functional, cognitive, and behavioral trajectories of FTD subtypes in a Spanish cohort, including assessments performed remotely during the COVID-19 pandemic. METHODS: Sixty-seven patients diagnosed with behavioral variant FTD (bvFTD), non-fluent variant primary progressive aphasia (nfvPPA), or semantic variant PPA (svPPA) were prospectively followed at Hospital Universitario 12 de Octubre (Madrid, Spain). Functional and neuropsychiatric status were evaluated using the Frontotemporal Dementia Rating Scale (FTD-FRS), the Interview for Deterioration in Daily Activities in Dementia (IDDD), the Neuropsychiatric Inventory (NPI), and the telephone Mini-Mental State Examination (T-MMSE). Thirty-three assessments were conducted remotely during pandemic restrictions. RESULTS: Over a mean follow-up of 3.1 years, significant declines were found in T-MMSE, FTD-FRS, and IDDD (p < 0.001), whereas NPI scores remained stable. The svPPA group exhibited the greatest cognitive and functional deterioration, while bvFTD showed more heterogeneous progression. Twelve participants (18%) died during follow-up, mainly older men with poorer baseline performance. CONCLUSION: Functional and cognitive decline in FTD varies across variants, with the semantic subtype showing the most aggressive course in our cohort. Remote assessments are feasible and valid for longitudinal monitoring.