Reliability and validity testing of a Chinese-translated version of the 39-item Parkinson's Disease Questionnaire (PDQ-39).

The trend toward international cooperation in research projects emphasizes the need to translate existing validated tools into local languages. The purpose of this study was to test the reliability and validity of a Chinese-translated version of the 39-item Parkinson's Disease Questionnaire (PDQ-39). Seventy-three Taiwanese individuals with Parkinson's disease were consecutively recruited. The internal consistency reliability was satisfactory for all domains (Cronbach's alpha = 0.80-0.96), except for the social support, cognition, and bodily discomfort domains (alpha = 0.58-0.63). The convergent validity was also supported by strong correlations between domains measuring related constructs of the PDQ-39 and Unified Parkinson's Disease Rating Scale (r = 0.81-0.86), and between those of the PDQ-39 and SF-36 (r = -0.70--0.93). Except for the bodily discomfort domain, all domains of the PDQ-39 significantly discriminated patients at different stages, as indicated by the Hoehn and Yahr scale. Overall, the results of this study are consistent with the reports of the PDQ-39 in other countries (e.g., UK, Spain, US, and Greece), which suggests that the PDQ-39 is appropriate for use among Taiwanese individuals with PD. This study lays the foundation for future combinations and comparisons of data cross-nationally.