Validation of the Danish version of the Dutch Multifactor Fatigue Scale in acquired brain injury

Research Objectives: To validate the Danish version of the 38-item Dutch Multifactor Fatigue Scale (DMFS) as a multidimensional measure of fatigue following acquired brain injury (ABI).

Design: Mixed methods consisting of a cross-sectional (study 1) and a cognitive interviewing (study 2) study.

Setting: A stroke unit and three outpatient brain injury rehabilitation centers in Denmark.

Participants: Study 1: A consecutive sample of 149 adults with ABI (mean age = 58 years, 62% male), including 49 stroke inpatients (median = 13 days post-stroke) and 100 outpatients (median = 9 months post-injury), majority (89%) with stroke. Study 2: A sub-group of nine stroke outpatients participated in cognitive interviewing (Three-Step Test-Interview).

Interventions: Not applicable.

Main Outcome Measures: Study 1: Measurement models were evaluated using confirmatory factor analysis, including measurement invariance testing across in- and outpatients. Study 2: Verbalized interpretative processes in item responding were evaluated with respect to construct theory of subscales using Framework Analysis.

Results: Study 1: Impact of Fatigue, RMSEA = .07, CFI = .98, ω = .90, Mental Fatigue, RMSEA = .07, CFI = .99, ω = .83, and Signs and Direct Consequences of Fatigue, RMSEA = .08, CFI = .94, ω = .78, provided acceptable fit and performed equally in both in- and outpatients with the two last-named being partially invariant. Coping with fatigue was not unidimensional, RMSEA = .15, CFI = .81, ω = .46, and Physical fatigue exhibited local dependence between Item 5 and 9. Study 2: All participants responded congruently to 25 out of 38 items. Five items were problematic to >50% of participants, and seven items demonstrated various response difficulties.

Conclusions: DMFS addresses multiple aspects of fatigue following ABI, specifically, and may assist rehabilitation targeting in both early and late rehabilitation settings. Subscale total scores on Coping with Fatigue and Physical Fatigue require careful interpretation, and a translation revision is recommended for various items. The convergence of findings using different methodological approaches strengthens the evidence on validity.

Author(s) Disclosures: None disclosed.