Kalkers NF, Galan I, Kerbrat A, Tacchino A, Kamm CP, O'Connell K, McGuigan C, Edan G, Montalban X, Uitdehaag BM, Mokkink LB. Differential item functioning of the Arm function in Multiple Sclerosis Questionnaire (AMSQ) by language, a study in six countries.
Mult Scler 2019;
27:90-96. [PMID:
31845614 DOI:
10.1177/1352458519895450]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
BACKGROUND
The Arm function in Multiple Sclerosis Questionnaire (AMSQ) has been developed as a self-reported measure of arm and hand functioning for patients with multiple sclerosis (MS). The AMSQ was originally developed in Dutch and to date translated into five languages (i.e. English, German, Spanish, French, and Italian).
OBJECTIVE
The aim of this study was to evaluate differential item functioning (DIF) of the AMSQ in these languages.
METHODS
We performed DIF analyses, using "language" as the polytomous group variable. To detect DIF, logistic regression and item response theory principles were applied. Multiple logistic regression models were evaluated. We used a pseudo R2 value of 0.02 or more as the DIF threshold.
RESULTS
A total of 1733 male and female patients with all subtypes of MS were included. The DIF analysis for the whole dataset showed no uniform or non-uniform DIF on any of the 31 items. All R2 values were below 0.02.
CONCLUSION
The AMSQ is validated in six languages. All items have the same meaning to MS patients in Dutch, English, German, Spanish, French, and Italian. This validation study enables use of the AMSQ in international studies, for monitoring treatment response and disease progression.
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