Validity and Reliability of the Persian Version of the Parkinson Disease Quality of Life (PDQL) Questionnaire

Abstract: Background & Aims: This study aimed to translate Parkinson Disease Quality of Life (PDQL) Questionnaire into Persian and test its reliability and validity in Iranian patients with Parkinson disease. Method: In order to standardize the questionnaire, a standard "Forward-Backward" translation, cognitive debriefing and cultural adaptation procedure were applied and the English version of PDQL was translated into Persian, the official language in Iran. Subjects were 108 patients with Parkinson referred to Motaharri Clinic in Shiraz. Demographic and epidemiological data concerning the disease stage were recorded. The reliability of the questionnaire was assessed by Koronbach`s alpha coefficient. Construct validity was assessed through factor analysis. Convergent and discriminate validity were assessed by spearman's correlation coefficient. Data were analyzed by SPSS 15. Results: In whole, 67 males (62.03%) and 41 females (37.97%) with Parkinson and mean ± SD age of 64.9±11.73 participated in this study. Koronbach`s alpha was 0.95. The range of convergent validity was 0.42-0.83 and that of discriminate validity was 0.15-0.70. The range of factorial analysis load was 0.119-0.801. Conclusion: The Persian version of the PDQL Questionnaire has a good structure. It is a reliable and valid instrument and can be used for measuring the effect of Parkinson on the quality of life. Keywords: PDQL, Parkinson, Validity, Reliabilit