Expanded and Independent Spanish Validation of the MDS‐Non Motor Rating Scale

Background:The Movement Disorder Society-sponsored Non-motor Rating Scale (MDS-NMS) assessthe severity and disability caused by non-motor symptoms (NMS) in Parkinson’s disease (PD).ObjectiveObjective:This article encapsulates the formal process for completing this program and the data on thefirstofficially approved non-English version of the MDS-NMS (Spanish).MethodsMethods:The MDS-NMS translation program involves four steps: translation and back-translation; cognitive pre-testing to ensure that raters and patients understand the scale and are comfortable with its content;field testingof thefinalized version; analysis of the factor structure of the tested version against the original English languageversion for the nine domains that could be analyzed in a confirmatory factor analysis. To be designated an“OfficialMDS translation,”the confirmatory factor analysis Comparative Fit Index had to be≥0.90.ResultsResults:The Spanish MDS-NMS was tested in 364 native-Spanish-speaking patients with PD from sevencountries. For all subjects with fully computable data with all domains of the MDS-NMS (n=349), theComparative Fit Index was≥0.90 for the nine eligible domains. Missing data were negligible and moderateflooreffect (42.90%) was found for the Non-Motor Fluctuations subscale. Item homogeneity coefficient wasadequate, and the correlation of the MDS-NMS domains with other measures for related constructs wasacceptable (rs≥0.50).ConclusionsConclusions:The Spanish version of the MDS-NMS followed the IPMDS Translation Program protocol, reachedthe criterion to be designated as an Official Translation, and is now available on the MDS website.