Defining ambulation status in patients with Duchenne muscular dystrophy using the 10-metre walk test and the motor function measure scale

Abstract

Purpose Timed functional tests have been explored to understand the natural history of Duchenne muscular dystrophy (DMD) and to establish warning signs of loss of gait. This study verified whether the combination of the 10-metre walk test (10MWT) and the motor function measure (MFM) could classify the ambulation status of DMD patients. Method Thirty-two patients, aged between 5 and 22 years, with independent gait initially evaluated over 11 years participated in the study. Two groups were created: ambulators and non-ambulators. For both groups, we calculated a 10MWT ratio, by dividing the time spent to perform the last evaluation by the penultimate evaluation, and a MFM dimension-1 score (MFM-D1), collected in the same period. For the statistical analysis, the CART algorithm (“rpart” package in R) classified the patients into ambulators and non-ambulators according to two continuous variables: the 10MWT ratio and the MFM-D1 score. Results The cut-off points were 1.1 for the 10MWT ratio and 26 points for the MFM-D1, which distinguished 70% of the patients as either ambulators or non-ambulators. Conclusion This simple measurement strategy can be used by therapists to adjust their rehabilitation strategies and goals. Implications for rehabilitation Combination of 10MWT ratio with MFM-D1 reveal an "indicator" for the ambulation status of patients with DMD. Physiotherapists can guide clinical care and prepare the patient and family for loss of gait. CART algorithm describes how we classified the patients according to two continuous variables. 70% Of the patients with DMD can be distinguished as either ambulators or non-ambulators.