Validation of the Hebrew Version of the Unified Dyskinesia Rating Scale

Background: The Unified Dyskinesia Rating Scale (UDysRS) is a well-established tool for producing comprehensive assessments of severity and disability associated with dyskinesia in patients with Parkinson's disease (PD). The scale was originally developed in English, and a broad international effort has been undertaken to develop and validate versions in additional languages. Our aim was to validate the Hebrew version of the UDysRS. Methods: We translated the UDysRS into Hebrew, back-translated it into English, and carried out cognitive pretesting. We then administered the scale to non-demented native Hebrew-speaking patients who fulfilled the Brain Bank diagnostic criteria for probable PD (n = 250). Data were compared to the Reference Standard data used for validating UDysRS translations. Results: The different portions of the Hebrew UDysRS showed high internal consistency (α ≥ 0.92). A confirmatory factor analysis in which we compared the Hebrew UDysRS to the Reference Standard version produced a comparative fit index (CFI) of 0.98, exceeding the threshold criterion of CFI > 0.9 indicating factor validity. A secondary exploratory factor analysis provided further support to the consistency between the factor structures of the Hebrew and Reference Standard versions of the UDysRS. Conclusion: The UDysRS Hebrew version shows strong clinimetric properties and fulfills the criteria for designation as an official International Parkinson and Movement Disorder Society-approved translation for use in clinical and research settings.