RESUMEN
STUDY DESIGN: Psychometric study. OBJECTIVE: The purpose of this study is to translate, culturally adapt and evaluate the validity and reliability of the Persian (Farsi) version of GLTEQ in patients with multiple sclerosis. METHODS: This study had three phases, including translation of the questionnaire into Persian and making cultural adaptation, evaluation of pre-final version of questionnaire's comprehensibility in a pilot study, and investigation of reliability and validity of the final version of the translated questionnaire. Content validity, and convergent validity (correlations among the Persian version of GLTEQ and Global physical activity questionnaire (GPAQ), and international physical activity questionnaire (IPAQ)) and after all test-retest reliability were studied. RESULTS: The subjects were 87 MS patients. The Persian version demonstrated moderate to good convergent validity; the correlation coefficient between the Persian version and GPAQ was r=0.64 (p<0.001), and between the Persian version and IPAQ was r=0.59 (p<0.001). The test-retest reliability was strong (Intra-class Correlation (ICC) value ranged between 0.908 and 0.992). Besides, its face validity and content validity were acceptable. CONCLUSIONS: The Persian version of GLTEQ is a valid and reliable instrument to assess physical activity in patients with MS. This questionnaire can be a step toward standardization of physical activity measurement in patients with MS. Also, in research, it provides the possibilities to carry on a comparative study across cultures using the same outcome measure.