Adaptation and validation of a Spanish-language version of the Frontotemporal Dementia Rating Scale (FTD-FRS).

INTRODUCTION The Frontotemporal Dementia Rating Scale (FTD-FRS) is a tool designed to aid with clinical staging and assessment of the progression of frontotemporal dementia (FTD-FRS). OBJECTIVE Present a multicentre adaptation and validation study of a Spanish version of the FRS. METHODOLOGY The adapted version was created using 2 translation-back translation processes (English to Spanish, Spanish to English) and verified by the scale's original authors. We validated the adapted version in a sample of consecutive patients diagnosed with FTD. The procedure included evaluating internal consistency, testing unidimensionality with the Rasch model, analysing construct validity and discriminant validity, and calculating the degree of agreement between the Clinical Dementia Rating scale (CDR) and FTD-FRS for FTD cases. RESULTS The study included 60 patients with DFT. The mean score on the FRS was 12.1 points (SD=6.5; range, 2-25) with inter-group differences (F=120.3; df=3; P<.001). Cronbach's alpha was 0.897 and principal component analysis of residuals delivered an acceptable eigenvalue for 5 contrasts (1.6-2.7) and 36.1% raw variance. FRS was correlated with the Mini-mental State Examination (r=0.572; P<.001) and functional capacity (DAD; r=0.790; P<.001). FTD-FRS also showed a significant correlation with CDR (r=-0.641; P<.001), but we did observe variability in the severity levels; cases appeared to be less severe according to the CDR than when measured with the FTD-FRS (kappa=0.055). CONCLUSIONS This process of validating the Spanish translation of the FTD-FRS yielded satisfactory results for validity and unidimensionality (severity) in the assessment of patients with FTD.