Validation of the Italian version of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale

The Movement Disorder Society-sponsored revision of the Unified Parkinson's Disease Rating Scale (MDS-UPDRS) has been available in English since 2008. As part of this process, the MDS-UPDRS organizing team developed guidelines for development of official non- English translations. We present here the formal process for completing officially approved non-English versions of the MDS-UPDRS and specifically focus on the first of these versions in Italian. The MDS-UPDRS was translated into Italian and tested in 377 native-Italian speaking PD patients. Confirmatory and exploratory factor analyses determined whether the factor structure for the English- language MDS-UPDRS could be confirmed in data col- lected using the Italian translation. To be designated an 'Official MDS translation,' the Comparative Fit Index (CFI) had to be C0.90 relative to the English-language version. For all four parts of the Italian MDS-UPDRS, the CFI, in comparison with the English-language data, was C0.94. Exploratory factor analyses revealed some differ- ences between the two datasets, however these differences were considered to be within an acceptable range. The Italian version of the MDS-UPDRS reaches the criterion to be designated as an Official Translation and is now avail- able for use. This protocol will serve as outline for further validation of this in multiple languages.