Successful use of the Unified Dyskinesia Rating Scale regardless of PD- or dyskinesia-duration.

Loading...
Thumbnail Image

Date

2019-10

Journal Title

Journal ISSN

Volume Title

Repository Usage Stats

65
views
26
downloads

Citation Stats

Abstract

OBJECTIVE:We assessed differential item functioning (DIF) in the Unified Dyskinesia Rating Scale (UDysRS) to evaluate bias risk from the duration of Parkinson's Disease (PD) and duration of dyskinesia. BACKGROUND:Assessing DIF is a core validation step for rating scales. If DIF is present for an item, interpretation must consider influences from the tested covariates. DIF can be uniform or non-uniform, depending on the consistency of influence from the given covariate across all levels of dyskinesia. METHODS:Using a large UDysRS database (N = 2313), uniform and non-uniform DIF related to the duration of PD and/duration of dyskinesia were tested. Unidimensionality of UDysRS was first confirmed using confirmatory factor analysis. DIF analysis was conducted using two independent latent models. DIF in an item was confirmed if both methods independently identified DIF at a significance level using Bonferroni correction. McFadden pseudo R^2 measured clinical relevancy of DIF magnitude (negligible, moderate, and large) for items identified with DIF, and items with DIF were considered clinically relevant if they exceeded a negligible designation. RESULTS:Most items did not show uniform or non-uniform DIF based on PD and dyskinesia duration in isolation or in combination. For all items where DIF was identified, the magnitude statistic was in the negligible range (McFadden pseudo R^2 < 0.035) and the combined impact of multiple identified DIF items on UDysRS likewise did not exceed the negligible designation. CONCLUSION:The absence of clinically relevant DIF suggests that the UDysRS can be applied across all patients regardless of their PD- or dyskinesia-duration.

Department

Description

Provenance

Citation

Published Version (Please cite this version)

10.1016/j.parkreldis.2019.08.019

Publication Info

Ren, Xuehan, Jeffrey Lin, Sheng Luo, Christopher G Goetz, Glenn T Stebbins and Esther Cubo (2019). Successful use of the Unified Dyskinesia Rating Scale regardless of PD- or dyskinesia-duration. Parkinsonism & related disorders, 67. pp. 113–116. 10.1016/j.parkreldis.2019.08.019 Retrieved from https://hdl.handle.net/10161/19677.

This is constructed from limited available data and may be imprecise. To cite this article, please review & use the official citation provided by the journal.

Scholars@Duke

Luo

Sheng Luo

Professor of Biostatistics & Bioinformatics

Unless otherwise indicated, scholarly articles published by Duke faculty members are made available here with a CC-BY-NC (Creative Commons Attribution Non-Commercial) license, as enabled by the Duke Open Access Policy. If you wish to use the materials in ways not already permitted under CC-BY-NC, please consult the copyright owner. Other materials are made available here through the author’s grant of a non-exclusive license to make their work openly accessible.