Validation of the fatigue scale for motor and cognitive functions in a danish multiple sclerosis cohort

Abstract

BackgroundOur objective was to validate the Danish translation of the Fatigue Scale for Motor and Cognitive Functions (FSMC) in multiple sclerosis (MS) patients. Materials and methodsA Danish MS cohort (n = 84) was matched and compared to the original German validation cohort (n = 309) and a healthy control cohort (n = 147). The Modified Fatigue Impact Scale (MFIS) was used as reference scale and Becks Depression Inventory-Fast Screen (BDI-FS) and Expanded Disability Status Scale (EDSS) for confounding factors. We assessed internal consistencies; convergent, divergent, and predictive validity; partial correlations correcting for depression; significant differences between the mean scores of the cohorts; and sensitivity and specificity with receiver operating characteristic (ROC) curves. ResultsExcellent internal consistencies for the total scale and subscales were found (α = 0.91–0.95). Strong positive correlations between the two fatigue scales implied high convergent validity (total scores: r = 0.851, p < 0.01). The two cohorts corresponded well when divided into subgroups (EDSS score; age; gender). Correcting for depression did not result in any significant adjustments of the correlations. The area under the curve (AUC) for the ROC curves represented excellent accuracy (Danish MS cohort, AUC = 0.9190; German MS cohort, AUC = 0.9034). ConclusionThe Danish translation of the FSMC has a high convergent validity with another measure of fatigue as well as excellent internal consistency and accuracy. It is found to be an applicable and recommendable measure of fatigue in Danish MS patients.