Turkish Standardization of Movement Disorders Society Unified Parkinson's Disease Rating Scale and Unified Dyskinesia Rating Scale

Abstract

Background: Movement Disorders Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and Unified Dyskinesia Rating Scale (UDysRS) were developed as standard tools to rate Parkinson's disease (PD) and drug-induced dyskinesias of PD. As these scales have become widely used, there is a need for translation to non-English languages. Here we present the standardization for the Turkish translations. Methods: The scales were translated into Turkish and then back-translated to English. These back-translations were reviewed by the MDS team. After cognitive pretesting, movement disorder specialists from nine centers tested 352 patients for MDS-UPDRS, and 250 patients for UDysRS. Confirmatory factor analyses (CFAs) were used to determine if the factor structures for the reference standards could be confirmed in the Turkish data. The comparative fit indexes (CFIs) for the scales were required to be 0.90 or higher. Exploratory factor analyses (EFAs) were conducted to explore the underlying factor structure without the constraint of a pre-specified factor structure. Results: For both scales, the CFIs were 0.94 or greater as compared to the reference standard factor structures. The factor structures were consistent with that of reference standards, although there were some differences in some areas as compared to the EFA of the reference standard dataset. This may be due to the inclusion of patients with different stages of PD and different cultural properties of raters and patients. Conclusions: These results demonstrate that the Turkish translations of MDS-UPDRS and UDysRS have adequate clinimetric properties. They are established as the official translations and can be reliably used in Turkish speaking populations.