Cross-cultural adaptation and psychometric evaluations of the Turkish version of Parkinson Fatigue Scale

Purpose The objectives of the present study were to translate and cross-culturally adapt the English version of the Parkinson Fatigue Scale into Turkish, to evaluate its psychometric properties, and to compare them with that of other language versions. Methods A total of 144 patients with idiopathic Parkinson disease were included in the study. The Turkish version of Parkinson Fatigue Scale was evaluated for data quality, scaling assumptions, acceptability, reliability, and validity. Results The questionnaire response rate was 100% for both test and retest. The percentage of missing data was zero for items, and the percentage of computable scores was full. Floor and ceiling effects were absent. The Parkinson Fatigue Scale provides an acceptable internal consistency (Cronbach's alpha was 0.974 for 1st test and 0.964 for a retest, and corrected item-to-total correlations were ranged from 0.715 to 0.906) and test-retest reliability (Cohen's kappa coefficients were ranged from 0.632 to 0.786 for individuals items, and intraclass correlation coefficient was 0.887 for the overall Parkinson Fatigue Scale Score). An exploratory factor analysis of the items revealed a single factor explaining 71.7% of variance. The goodness-of-fit statistics for the one-factorial confirmatory factor analysis were Tucker Lewis index=0.961, comparative fit index=0.971 and root mean square error of approximation=0.077 for a single factor. The average Parkinson Fatigue Scale Score was correlated significantly with sociodemographic data, clinical characteristics and scores of rating scales. Conclusions The Turkish version of the Parkinson Fatigue Scale seems to be culturally well adapted and have good psychometric properties. The scale can be used in further studies to assess the fatigue in patients with Parkinson's disease.