Forjaz, Maria JoãoAyala, AlbaTesta, Claudia MBain, Peter GElble, RodgerHaubenberger, DietrichRodriguez-Blazquez, CarmenDeuschl, GüntherMartínez-Martín, Pablo2019-08-012019-08-012015-07Mov Disord. 2015 Jul;30(8):1139-43.08853185http://hdl.handle.net/20.500.12105/8096Background: This article proposes an International Parkinson and Movement Disorder Society (MDS)-UPDRS tremor-based scale and describes its measurement properties, with a view to developing an improved scale for assessing tremor in Parkinson's disease (PD). Methods: This was a cross-sectional, multicenter study of 435 PD patients. Rasch analysis was performed on the 11 MDS-UPDRS tremor items. Construct validity, precision, and test-retest reliability were also analyzed. Results: After some modifications, which included removal of an item owing to redundancy, the obtained MDS-UPDRS tremor scale showed moderate reliability, unidimensionality, absence of differential item functioning, satisfactory convergent validity with medication, and better precision than the raw sum score. However, the scale displayed a floor effect and a need for more items measuring lower levels of tremor. Conclusions: The MDS-UPDRS tremor scale provides linear scores that can be used to assess tremor in PD in a valid, reliable way. The scale might benefit from modifications and studies that analyze its responsiveness.engAMhttp://creativecommons.org/licenses/by-nc-sa/4.0/MDS-UPDRSParkinson's diseaseRasch analysisTremorAgedCross-Sectional StudiesFemaleHumansMaleMiddle AgedParkinson DiseasePsychometricsReproducibility of ResultsTremorSeverity of Illness IndexAtribución-NoComercial-CompartirIgual 4.0 Internacional260962103081139-4310.1002/mds.262711531-8257Movement disorders : official journal of the Movement Disorder Societyopen access