psychometric properties of the persian version of the fatigue impact scale (fis-p) in patients with multiple sclerosis

objectives: this study was designed to evaluate the psychometric features of the persian version of the fatigue impact scale (fis-p) tool when used in iranian ms patients. methods: 140 ms patients and the equivalent number of healthy controls completed the following assessments: fis-p, fatigue severity scale (fss), sf-36 questionnaire and  the mini-mental state examination (mmse).  results: a significant inverse correlation between fis and the quality of life (sf-36 assessment tool), as well as a positive and significant correlation with the fss were noted. the intraclass correlation coefficient (icc) values for the inter-rater reliability for the physical, cognitive, and social sections and the whole questionnaire were 0.89, 0.86, 0.95 and 0.98, respectively. the fis persian version was shown to possess a high reliability (with a cronbach’s alpha  of 0.953). likewise, the icc values for the test-retest reliability were 0.86, 0.87, 0.92 and 0.93 for the physical, cognitive, social subscales and the whole questionnaire, respectively. this suggested a high reliability for the fis-p. discussion: with a proper validity and reliability, the persian-version of fis retains the capability for being used in the assessment of fatigue and evaluation of the treatment and rehabilitation effects on fatigue-related symptoms among persian-speaking patients with ms.