6-minute walk test as a measure of disease progression and fatigability in a cohort of individuals with RYR1-related myopathies

Abstract

The six-minute walk test (6MWT) is an endurance test with high reliability and validity used to measure walking capacity, disease progression, and more recently, fatigability in NMDs with limited results in RYR1-RM. [...]the purpose of our study is to objectively assess disease progression and fatigability in RYR1-RM affected individuals using the 6MWT. The fastest speed was achieved in the first minute at both baseline and 6-month visits. Because the variability in speed was observed at baseline but not at the 6-month visit, this variability could be attributed to a learning effect, which is common in other NMDs [27, 28]. Given our study shows that fatigability can be captured within the first 2 min of the 6MWT, this may further support the use of a 2MWT but needs to be explored further. Since the 6MWT detects a decline in walking speed in RYR1-RM, prospectively studying cardiorespiratory measures of fatigue during the 6MWT could provide insight into the cardiorespiratory response of individuals with RYR1-RM. Study limitations Given the rare nature of this disease, a few limitations to our study include the small sample size and varied disease expression among participants, which limits our ability to categorize by severity. [...]we were unable to observe whether performances varied by disease severity or by the presence of neuromuscular issues that limited walking in some cases.