Minute-by minute gait variations during the 6-Minute walk test in subjects with myotonic dystrophy type 1

Myotonic Dystrophy Type 1 is a rare multisystem disorder, with symptoms including progressive muscle weakness, myotonia and fatigue. Although mobility measures are now common in several tests performed in clinics, their quantification using wearable sensors have not been significantly explored in the literature. This study investigated variation of gait characteristics during prolonged walking in individuals with Myotonic Dystrophy Type 1 using a single wearable sensor, and their association with gait fatigability proxies.

Forty-two subjects with Myotonic Dystrophy Type 1 and 15 healthy controls performed a 6-min walk test while wearing a single lumbar-mounted inertial measurement unit. Minute-by-minute gait parameters were extracted and compared between groups using repeated-measures ANOVA. Correlation analysis was performed to examine whether changes in gait parameters were related to motor functional ability levels.

Patients demonstrated significantly impaired gait compared to controls, with reduced speed, cadence, step length, and increased stride time variability. While controls and mildly affected subjects showed similar temporal patterns, including a speed decrease in mid-test followed by recovery in the final minute, moderately affected subjects maintained a stable but slower pace throughout. Changes in cadence across the test were weakly but significantly correlated with clinical disability measures.

Wearable sensors worn during prolonged walking assessments can detect subtle gait alterations in Myotonic Dystrophy Type 1 that vary by disability level, potentially serving as objective outcome measures for monitoring disease progression and evaluating therapeutic interventions.

The trial was retrospectively registered in Clinicaltrials.gov (NCT06666816, date of registration 31/10/2024). URL: https://clinicaltrials.gov/study/NCT06666816.