Evaluation of fatigue and fatigability in people with Duchenne muscular dystrophy using a dynamic arm support – a pilot study

Abstract

Background Due to progressive muscle wasting and weakness in patients with Duchenne Muscular Dystrophy (DMD), physical fatigability increases, upper extremity function reduces, which negatively impacts quality of life. Assistive technology such as dynamic arm supports (DAS) may help reduce this fatigability. This study aims to assess whether the novel Yumen ‘EXone’ DAS can reduce upper extremity fatigue and fatigability in DMD patients and healthy controls (HC), both with and without the DAS. Additionally, longitudinal changes in DMD patients were evaluated. Methods Five DMD patients from the Yumen Bionics pioneer program and five HCs participated. Two submaximal tests simulating drinking and reaching were performed for two minutes, each with and without DAS. DMD participants completed these tests twice, at baseline (T0) and after 6-9 months (T1), while HCs completed them once. Physical fatigability was measured by the number of repetitions and changes in surface electromyography (sEMG) amplitude. Subjective fatigue was assessed using the Borg Scale (6-20) Rate of Perceived Exertion (RPE). Results DMD participants generally performed more repetitions with the DAS than without. HCs showed similar or increased repetitions with the DAS. Assessing fatigability with sEMG was difficult due to the compensatory mechanisms used for the tests. Subjective fatigue scores on the Borg Scale were lower with the DAS for both DMD patients and HCs. Conclusion The Yumen ‘EXone’ DAS effectively reduces both fatigue and fatigability in DMD patients and healthy controls. Despite the methodological shortcomings, this research is one of the first studies investigating the impact of DAS on fatigue and fatigability.