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

Abstract

Background The Movement Disorder Society‐sponsored Non‐motor Rating Scale (MDS‐NMS) assess the severity and disability caused by non‐motor symptoms (NMS) in Parkinson's disease (PD). Objective This article encapsulates the formal process for completing this program and the data on the first officially approved non‐English version of the MDS‐NMS (Spanish). Methods 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 testing of the finalized version; analysis of the factor structure of the tested version against the original English language version for the nine domains that could be analyzed in a confirmatory factor analysis. To be designated an “Official MDS translation,” the confirmatory factor analysis Comparative Fit Index had to be ≥0.90. Results The Spanish MDS‐NMS was tested in 364 native‐Spanish‐speaking patients with PD from seven countries. For all subjects with fully computable data with all domains of the MDS‐NMS (n = 349), the Comparative Fit Index was ≥0.90 for the nine eligible domains. Missing data were negligible and moderate floor effect (42.90%) was found for the Non‐Motor Fluctuations subscale. Item homogeneity coefficient was adequate, and the correlation of the MDS‐NMS domains with other measures for related constructs was acceptable (rs ≥ 0.50). Conclusions The Spanish version of the MDS‐NMS followed the IPMDS Translation Program protocol, reached the criterion to be designated as an Official Translation, and is now available on the MDS website.