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

dc.contributor.author Ren, Xuehan
dc.contributor.author Lin, Jeffrey
dc.contributor.author Luo, Sheng
dc.contributor.author Goetz, Christopher G
dc.contributor.author Stebbins, Glenn T
dc.contributor.author Cubo, Esther
dc.date.accessioned 2020-01-01T15:45:43Z
dc.date.available 2020-01-01T15:45:43Z
dc.date.issued 2019-10
dc.identifier S1353-8020(19)30375-X
dc.identifier.issn 1353-8020
dc.identifier.issn 1873-5126
dc.identifier.uri https://hdl.handle.net/10161/19677
dc.description.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.
dc.language eng
dc.publisher Elsevier BV
dc.relation.ispartof Parkinsonism & related disorders
dc.relation.isversionof 10.1016/j.parkreldis.2019.08.019
dc.subject Clinimetrics
dc.subject Differential item functioning
dc.subject Dyskinesia
dc.subject Parkinson's disease
dc.subject Rating scales
dc.title Successful use of the Unified Dyskinesia Rating Scale regardless of PD- or dyskinesia-duration.
dc.type Journal article
duke.contributor.id Luo, Sheng|0796693
dc.date.updated 2020-01-01T15:45:42Z
pubs.begin-page 113
pubs.end-page 116
pubs.organisational-group School of Medicine
pubs.organisational-group Duke
pubs.organisational-group Duke Clinical Research Institute
pubs.organisational-group Institutes and Centers
pubs.organisational-group Biostatistics & Bioinformatics
pubs.organisational-group Basic Science Departments
pubs.publication-status Published
pubs.volume 67
duke.contributor.orcid Luo, Sheng|0000-0003-4214-5809


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