Seebacher, B, Horton, MC orcid.org/0000-0002-6675-7335, Reindl, M et al. (4 more authors) (2023) Psychometrische Prüfung des deutschsprachigen „Neurologischen Fragebogens zur Müdigkeit bei Multipler Sklerose (NFI-MS-G)“ bei Rehabilitanden mit Multipler Sklerose (Psychometric Evaluation of the ‘German Neurological Fatigue Index for Multiple Sclerosis (NFI-MS-G)’ in a Sample of Rehabilitation Patients with Multiple Sclerosis). Die Rehabilitation, 62 (01). pp. 31-39. ISSN 0034-3536
Abstract
Purpose The purpose of this study was to provide a patient-reported outcome measure for people with multiple sclerosis (MS) comprehensively reflecting the construct of fatigue and developed upon the assumptions of the Rasch model. The Neurological Fatigue Index – Multiple Sclerosis (NFI-MS) is based on both a medical and patient-described symptom framework of fatigue and has been validated. Therefore, in this study the German version of the NFI-MS (NFI-MS-G) consisting of a physical and cognitive subscale and a summary scale was validated.
Method In this bi-centre-study, 309 people with MS undergoing outpatient rehabilitation or being≥2 months before or after their inpatient rehabilitation completed the German NFI-MS-G twice within 14–21 days together with other questionnaires. Correlation with established questionnaires and Rasch analysis were used for its validation. Additionally, psychometric properties of known-groups validity, internal consistency, test-retest reliability, measurement precision and readability were tested. Finally, the English NFI-MS and German NFI-MS-G were compared with each other to equate the language versions.
Results The NFI-MS-G showed good internal construct validity, convergent and known-groups validity and internal consistency (Cronbach’s alpha 0.84–0.93). The physical subscale showed minor local dependencies between items 1 and 7, 2 and 3 and 4 to 6, that could be treated by combining the respective items to testlets. Unidimensionality was found for the physical and cognitive subscales but not for the summary scale. Replacing the summary scale, a 2-domains subtest measuring the higher-order construct of fatigue was created. Good test-retest reliability (Lin’s concordance correlation coefficient of 0.86–0.90) and low floor and ceiling effects were demonstrated. The NFI-MS-G was found easily readable and invariant across groups of gender, age, disease duration, timepoint and centre.
Conclusion The German version of the NFI-MS comprehensively represents the construct of fatigue and has adequate psychometric properties. The German version differs from the English original version with respect to a lack of unidimensionality of the summary scale and minor local dependencies of the physical subscale that could be canceled out using a testlet analysis.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/). |
Keywords: | Multiple Sclerosis; Fatigue; Patient Reported Outcome Measures; Austria; Validation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Medicine (Leeds) > Institute of Rheumatology & Musculoskeletal Medicine (LIRMM) (Leeds) > Rehabilitation Medicine (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 09 Jan 2023 12:45 |
Last Modified: | 08 Nov 2023 14:07 |
Status: | Published |
Publisher: | Thieme Gruppe |
Identification Number: | 10.1055/a-1903-4483 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:194885 |