Forjaz, Maria JoãoAyala, AlbaMartínez-Martín, PabloDujardin, KathyPontone, Gregory MStarkstein, Sergio EWeintraub, DanielLeentjens, Albert F G2019-08-012019-08-012015-04Mov Disord. 2015 Apr;30(4):545-51.08853185http://hdl.handle.net/20.500.12105/8095The Parkinson Anxiety Scale is a new scale developed to measure anxiety severity in Parkinson's disease specifically. It consists of three dimensions: persistent anxiety, episodic anxiety, and avoidance behavior. This study aimed to assess the measurement properties of the scale while controlling for the rater (self- vs. clinician-rated) effect. The Parkinson Anxiety Scale was administered to a cross-sectional multicenter international sample of 362 Parkinson's disease patients. Both patients and clinicians rated the patient's anxiety independently. A many-facet Rasch model design was applied to estimate and remove the rater effect. The following measurement properties were assessed: fit to the Rasch model, unidimensionality, reliability, differential item functioning, item local independency, interrater reliability (self or clinician), and scale targeting. In addition, test-retest stability, construct validity, precision, and diagnostic properties of the Parkinson Anxiety Scale were also analyzed. A good fit to the Rasch model was obtained for Parkinson Anxiety Scale dimensions A and B, after the removal of one item and rescoring of the response scale for certain items, whereas dimension C showed marginal fit. Self versus clinician rating differences were of small magnitude, with patients reporting higher anxiety levels than clinicians. The linear measure for Parkinson Anxiety Scale dimensions A and B showed good convergent construct with other anxiety measures and good diagnostic properties. Parkinson Anxiety Scale modified dimensions A and B provide valid and reliable measures of anxiety in Parkinson's disease that are comparable across raters. Further studies are needed with dimension C.engAMhttp://creativecommons.org/licenses/by-nc-sa/4.0/Parkinson's diseaseRasch analysisAnxietyRaterAdultAgedAtribución-NoComercial-CompartirIgual 4.0 Internacional25546697304545-5110.1002/mds.261111531-8257Movement disorders : official journal of the Movement Disorder Societyopen access