Differential item functioning of the Arm function in Multiple Sclerosis Questionnaire (AMSQ) by language, a study in...

Area of Science:

• Neuroscience
• Clinical Psychology
• Rehabilitation Medicine

Background:

• The Arm function in Multiple Sclerosis Questionnaire (AMSQ) is a self-report measure for arm and hand functioning in multiple sclerosis (MS).
• The AMSQ was initially developed in Dutch and subsequently translated into English, German, Spanish, French, and Italian.

Purpose of the Study:

• To evaluate the differential item functioning (DIF) of the AMSQ across its translated versions.
• To ensure the cross-cultural validity and reliability of the AMSQ for international use.

Main Methods:

• Differential item functioning (DIF) analyses were conducted using "language" as the polytomous group variable.
• Logistic regression and item response theory principles were applied to detect DIF.
• A pseudo R² value of 0.02 or higher was used as the threshold for DIF detection.

Main Results:

• A total of 1733 male and female patients with all subtypes of MS were included in the study.
• No uniform or non-uniform DIF was found on any of the 31 AMSQ items across the analyzed languages.
• All R² values were below the 0.02 DIF threshold, indicating consistent item performance.

Conclusions:

• The AMSQ is validated for use in six languages, demonstrating its reliability for assessing arm and hand function in MS patients.
• All items of the AMSQ hold consistent meaning for patients across Dutch, English, German, Spanish, French, and Italian versions.
• This validation supports the use of the AMSQ in international studies for monitoring treatment response and disease progression in multiple sclerosis.