Validity And Reliability Testing Of The Mainland Chinese Version Of The Parkinson's Disease Questionnaire (PDQ-39)

Objective:To assess the Mainland Chinese version of the 39-item Parkinson's Disease Questionnaire (PDQ-39).Methods:Seventy-one patients with Parkinson's Disease (PD) completed the PDQ-39 and the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) by themselves. All the participants were retested with the PDQ-39 a week later. The United Parkinson's Disease Rating Scale (UPDRS) and the Hoehn and Yahr scale (H&Y) were used to evaluate the patients. Reliability was assessed by Cronbach's a and intra-class correlation coefficients (ICC). Validity was examined in terms of agreement with SF-36, UPDRS and H&Y scales.Results:The Mainland Chinese version of the PDQ-39 demonstrated acceptable reliability (Cronbach'sα=0.84-0.88; ICC:0.56-0.82). Item-total correlations (0.33-0.88) and scaling success rates (mean:77.56%) indicated satisfactory convergent and discriminant validity of the PDQ-39 items. The correlations between related constructs of the PDQ-39 and UPDRS (r=0.44-0.68), and between those of the PDQ-39 and SF-36 (r=-0.46--0.69) were all statistically significant (p<0.01). Except for stigma, cognitions and bodily discomfort, all other dimensions of the PDQ-39 significantly discriminated patients at different H&Y stages indicated by the H&Y scale.Conclusions:lthough our observations indicate that some problematic subscales of this version of the PDQ-39 could be improved upon, this study suggests acceptable reliability and validity of the Mainland Chinese version of the PDQ-39.