COPENHAGEN—Long walking capacity tests and the Multiple Sclerosis (MS) Walking Scale-12 may be more appropriate than short walking tests (eg, the Timed 25-Foot walk) in detecting clinically meaningful improvement after rehabilitation, according to research presented at the 29th Congress of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS).
In addition, walking capacity measures, but not the MS Walking Scale-12, may be more sensitive in detecting change in mildly disabled individuals than in moderately to severely disabled individuals with MS, said Ilse Baert, PhD, post-doctoral researcher in rehabilitation at Hasselt University in Diepenbeek, Belgium.
Patients Assessed Before and After Rehabilitation
To gauge the comparative responsiveness of five walking measures for patients with MS, Dr. Baert and colleagues performed a study at 17 centers in nine countries participating in the European Rehabilitation in MS network for best practices and research. The researchers categorized 290 patients with MS into two subgroups. Patients in the mild disability subgroup had Expanded Disability Status Scale (EDSS) scores of 4 or lower, and patients in the moderate to severe disability subgroup had EDSS scores greater than 4.
At baseline, the investigators assessed participants using the Timed 25-Foot Walk at usual speed, the Timed 25-Foot Walk at a fast speed, a two-minute walk test, a six-minute walk test, and the MS Walking Scale-12. Patients subsequently underwent a rehabilitation program that lasted between three weeks and three months. The researchers assessed patients with all five walking tests again after rehabilitation.
A clinical global impression of change scale, from patients’ and therapists’ perspectives, was chosen as an external criterion for determining responsiveness. To compare the responsiveness of the walking scales, Dr. Baert’s group calculated the area under the receiver operating characteristic curve. An outcome measure was considered not to be responsive if this value was less than 0.5. To provide reference values for clinically meaningful improvement, the researchers calculated the minimally important change, defined as the mean change score in patients who showed a minimally important change according to the external criterion. To quantify the real change (ie, measurement error), the group calculated the smallest real change.
Responsiveness and Clinically Meaningful Changes of Walking Measures
All participants had significantly better walking performance after rehabilitation, regardless of their disability levels. Overall, the MS Walking Scale-12 was the most responsive test, followed by, in order of decreasing responsiveness, the six-minute walk test, the two-minute walk test, the Timed 25-Foot Walk at fast speed, and the Timed 25-Foot Walk at usual speed.
In the mild disability subgroup, the rank of responsiveness of walking tests depended on the perspective. From the patients’ perspective, the two- and six-minute walk tests were more responsive than the Timed 25-Foot Walk test and the MS Walking Scale-12. From the therapists’ perspective, the MS Walking Scale-12 was the most responsive, followed by the Timed 25-Foot Walk at fast speed, the two- and six-minute walk tests, and the Timed 25-Foot Walk at usual speed. In the moderate to severe disability subgroup, the MS Walking Scale-12 and long walking capacity tests were more responsive than short walking tests from the patients’ and therapists’ perspectives.
The investigators found clinically meaningful differences after rehabilitation for three tests. For the two-minute walk test, improvements were 9.6 m from the patients’ perspective and 6.8 m from the therapists’ perspective. For the six-minute walk test, improvement was 21.6 m from the patients’ perspective. Scores on the MS Walking Scale-12 decreased by 10.4 from the patients’ perspective and by 11.4 from the therapists’ perspective. These clinically meaningful improvements exceeded measurement error.
—Erik Greb
Senior Associate Editor