Incidence of frontotemporal disorders in Olmsted County: A population-based study

Introduction: Frontotemporal dementia disorders (FTDs) are heterogeneous phenotypical behavioral and language disorders usually associated with frontal and/or temporal lobe degeneration. We investigated their incidence in a population-based cohort. Methods: Using a records-linkage system, we identified all patients with a diagnostic code for dementia in Olmsted County, MN, 1995-2010, and confirmed the diagnosis of FTD. A behavioral neurologist verified the clinical diagnosis and determined phenotypes. Results: We identified 35 FTDs cases. Overall, the incidence of FTDs was 4.3/100,000/year (95% CI: 2.9, 5.7). Incidence was higher in men (6.3/100,000, 95% CI 3.6, 9.0) than women (2.9/100,000; 95% CI: 1.3, 4.5); we observed an increased trend over time (B = 0.83, 95% CI: 0.54, 1.11, P < .001). At autopsy, clinical diagnosis was confirmed in eight (72.7%) cases. Discussion: We observed an increased incidence and trends of FTDs over time. This may reflect a better recognition by clinicians and improvement of clinical criteria and diagnostic tools.