Translation, cross-cultural adaptation and Turkish validation of the 25-Question Geriatric Locomotive Function Scale

Abstract

The 25-Question Geriatric Locomotive Function Scale (GLFS-25) is an assessment tool developed by Japanese researchers to evaluate locomotive functions in older adults. The purpose of this study is to translate and culturally adapt the GLFS-25 for use in Turkey, then determine the scale’s reliability and validity in the Turkish con text. A total of 264 older adults (124 males; mean age: 71.7±6.2 years) participated in the study. To assess test–retest reliability, 248 participants (112 males; mean age: 71.8±6.2 years) completed the GLFS-25 twice, with an interval of 3 to 14 days. Construct validity was evaluated using the Katz Index of Activities of Daily Living (ADL) and the Lawton Instrumental Activities of Daily Living Scale (IADL). Con vergent validity was assessed on the Visual Analogue Scale (VAS) for pain and the Geriatric Depression Scale. The GLFS-25 Turkish showed excellent internal con sistency with Cronbach’s alpha coefficient=0.95 (95% CI=0.95–0.96). Similarly, The GLFS-25 Turkish showed very high test-retest reliability with ICC=0.96 (95% CI=0.94–0.97). Correlations were good between GLFS-25 Turkish version and the Katz ADL (r = -0.62), Lawton IADL indices (r = -0.63), VAS-rest (r = -0.61), VAS-activity (r = -0.64), VAS-night (r = -0.63), and Geriatric Depression Scale (r = -0.67) (p=0.001). We observed no ceiling and floor effects. The Turkish version of the GLFS-25 demonstrated good reliability and validity and can be effectively utilized to assess locomotive functions in Turkish-speaking older adults. This scale can be provides clinicians and researchers with a culturally adapted, psychometri cally sound tool for evaluating mobility-related impairments in this population.