Abstract
INTRODUCTION: We investigated international differences in facial emotion recognition (FER) across stages of frontotemporal dementia (FTD). Previous studies may have missed early decline by combining data and masking variations in FER across countries. METHODS: An FER test was administered to 159 individuals with behavioral variant FTD, 521 presymptomatic pathogenic variant carriers, and 583 controls from 16 countries of residence. Linear mixed models assessed age, sex, education, and country effects on FER. Voxel-based morphometry examined neural correlates across countries. REULTS: Country accounted for 18%-18.3% of FER variance in presymptomatic carriers and controls and 9.9% in individuals with behavioral variant of FTD (bvFTD). Cross-country differences interacted with the effects of sex, age, and education. Neural correlates involving the frontal lobe and basal ganglia were identified in individuals with bvFTD, but no cross-country differences were found. DISCUSSION: These results underscore the need for culturally sensitive FER tools in research and clinical practice, especially as global multinational clinical trials emerge. HIGHLIGHTS: Performance on a test for facial emotion recognition (FER) varies between countries. The percentage of variance is lower in the behavioral variant of frontotemporal dementia (bvFTD) compared to presymptomatic pathogenic variant carriers and healthy controls. Cross-country differences interacted with the effects of sex, age, and education. There were no differences in brain correlates of FER across countries.