Effect of diagnostic criteria on prevalence of frontotemporal dementia in the elderly.

ABSTRACT

BACKGROUND: Frontotemporal dementia (FTD) is believed to be rare in the elderly, and the influence of different criteria on the prevalence of FTD is unclear. METHODS: Population-based samples of 70- to 95-year-olds (n = 2462) in Gothenburg, Sweden, underwent neuropsychiatric examinations. Behavioral variant FTD (bvFTD) was diagnosed according to the International Behavioural Variant FTD Criteria Consortium (FTDC), the Frontotemporal Lobe Degeneration Consensus criteria, and the Lund-Manchester Research Criteria. A subset (n = 1074) underwent computerized tomography (CT) of the brain. RESULTS: The prevalence of bvFTD varied between 0.2% and 0.5% at age 70 to 79 years, between 2.5% and 3.6% at age 80 to 89 years, and between 1.7% and 2.2% at age 90 to 95 years. The agreement between different criteria was low to moderate (κ = 0.20-0.42). Among those with bvFTD according to FTDC, 93.3% had frontal and/or temporal lobar atrophy on CT, compared with 12.6% of those without bvFTD (P < .001). CONCLUSIONS: The prevalence of bvFTD was higher than expected in this population. To a large extent, different criteria captured different individuals.