Validity and reliability of the Persian version of the multiple sclerosis quality of life questionnaire.

BACKGROUND AND AIMS To translate and test the reliability and validity of the Multiple Sclerosis Quality of Life Questionnaire (MSQoL-54) in Iranian MS patients. SETTING AND DESIGN Using a standard "forward-backward" translation, cognitive debriefing and cultural adaptation procedure, the English version of the MSQoL-54 was translated to Persian which is the Iranian official language. MATERIALS AND METHODS The subjects were multiple sclerosis (MS) patients referred to Motaharri clinic, Shiraz, South of Iran. Demographic data were recorded. Epidemiological data concerning MS type, duration of the disease, Functional System Score (FSS) and Expanded Disability Status Scale (EDSS) of patients were also provided by a qualified neurologist. STATISTICAL ANALYSIS The reliability of the questionnaire was assessed by Cronbach's alpha coefficient. Construct validity was assessed through factor analysis. Factor analysis was performed to determine that the Persian version is a two-dimensional measure including physical and mental parameters. RESULTS Multiple sclerosis patients (female:106 (75.2%), male:35 (24.8%)), with a mean+/-SD age of 32.2+/-9.8 years were enrolled in the study. Cronbach's alpha was 0.962. There were no significant differences between each item and the mean of physical and mental scores of MSQoL-54, regarding sex, marital status and education. There was a negative significant correlation between EDSS and physical health, role limitation due to physical problems, pain, energy, health perception, social function, cognitive function, health distress, overall Quality of Life. The scaling success rates were 100%, demonstrating convergent validity of each scale. Factor analysis confirmed the construct validity of the questionnaire. CONCLUSIONS The Persian version of the MSQoL-54 questionnaire has a good structural characteristic, it is a reliable and valid instrument and can be used for measuring the effect of MS on the Quality of Life.