Secondary abstract: |
Introduction: Since there is no specific measurement tool to assess mobility in patients with muscular dystrophy, we were interested in the feasibility of the de Morton Mobility Index (DEMMI) and in comparing the 6-minute walk test (6MWT) and the 2-minute walk test (2MWT), which are already used in clinical practise in patients with muscular dystrophy. Purpose: To test the feasibility of the DEMMI, the 6MWT, the 2MWT and their discriminant and convergent validity in patients with facioscapulohumeral muscular dystrophy (FSHD) and limb girdle muscular dystrophy (LMGD). Methods: Twenty-one subjects with LGMD and twenty-one subjects with FSHD, all aged between 31 and 80 years, were included in the study. First, data on their walking abilities were collected (functional ambulation classification - FAC in 6 categories). The subjects were first assessed with the DEMMI. Only subjects who achieved a FAC score between 3-6 could proceed to the 2MWT and the 6MWT. The Mann-Whitney U test was used to detect differences between subjects in the two subgroups for the DEMMI score, while the independent samples t-test was used for the 2MWT and 6MWT scores. The correlation between the measurement instruments was determined using the Pearson correlation coefficient. The floor-ceiling effect was determined by the proportion of subjects with the lowest and highest possible score or inability to perform the walk test. Results: The floor effect was observed for DEMMI in subjects with LMGD. In addition, the floor effect was also observed for both walk tests in subjects of both subgroups. There was a statistically significant difference in DEMMI scores between subjects in the two subgroups. On average, subjects with FSHD scored higher. There were no statistically significant differences in 2MWT and 6MWT scores between the two subgroups. The convergent validity of the DEMMI with the two walking tests was high to very high. For subjects with LMGD, we found no statistically significant correlations between the results of the DEMMI and the results of the two walk tests (2MWT and 6MWT). For all subjects together and for each subgroup separately, we found a statistically significant and excellent positive correlation between the 2MWT and 6MWT results. Conclusion: In clinical practise, the use of DEMMI would be useful and practical for patients with FSHD and LMGD until they are able to move around the bed. The 2MWT is appropriate for patients with lower ambulation, increased fatigue and poorer balance. Due to its excellent correlation with the 6MWT, it can also be used for patients with good walking ability. |