Activity-based training with the Myosuit: a safety and feasibility study across diverse gait disorders

Abstract

Background: Physical activity is a recommended part of treatment for numerous neurological and neuromuscular disorders. Yet, many individuals with limited mobility are not able to meet the recommended activity levels. Lightweight, wearable robots like the Myosuit promise to facilitate functional ambulation and thereby physical activity. However, there is limited evidence of the safety and feasibility of training with such devices.

Methods: Twelve participants with diverse motor disorders and the ability to walk for at least 10 m were enrolled in this uncontrolled case series study. The study protocol included five training sessions with a net training time of 45 min each. Primary outcomes were the feasibility of engaging in training with the Myosuit, the occurrence of adverse events, and participant retention. As secondary outcomes, we analyzed the walking speed using the 10-m Walk Test (10MWT) and for three participants, walking endurance using the 2-min Walk Tests.

Results: Eight out of 12 participants completed the entire study protocol. Three participants withdrew from the study or were excluded for reasons unrelated to the study. One participant withdrew because of an unsafe feeling when walking with the Myosuit. No adverse events occurred during the study period for any of the participants and all scheduled trainings were completed. For five out of the eight participants that completed the full study, the walking speed when using the Myosuit was higher than to their baseline walking speed.

Conclusions: Activity-based training with the Myosuit appears to be safe, feasible, and well-tolerated by individuals with diverse motor disorders.

Keywords: Exomuscle; Exoskeleton; Exosuit; Muscle dystrophy; Rehabilitation; Robot-assisted; Spinal cord injury; Stroke; Training.

Conflict of interest statement

FLH, PW and MX have no competing interests to declare. KS, JED and RR are authors of the European patent application 16207252.4 filed by ETH Zurich and licensed by MyoSwiss AG. KS is co-founder and CTO of MyoSwiss AG. JED is co-founder and CEO of MyoSwiss AG.

Figures

Fig. 1

a Schematic drawing of the Myosuit. On each leg, an actuated cable is routed across the hip and knee joints and driven by electric motors contained in a backpack unit. b The motors tension the cables to apply forces assisting hip and knee extension against gravity during parts of the stance phase of walking. From terminal stance into swing, the springs assist hip flexion. c Exemplary picture of training with the Myosuit

Fig. 2.

10MWT walking speed measured in trainings 1 to 4 with Myosuit assistance, relative to baseline 10MWT speed measured without the Myosuit in training 0. During the training blocks, the participants completed an individualized program comprising walking, balance and strength exercises. 10MWTs were performed at the beginning and end of training session, except for P6, P7 and P8, where only one 10MWT was performed at the beginning of the session and a 2minWT in place of the second 10MWT towards the end of the session (see also Fig. 3). Data points and baseline are calculated as the mean of the two 10MWTs during the respective session, and as the result from only the first 10MWT for P6, P7 and P8

Fig. 3

Distance covered in 2minWT during trainings 1 to 4 with Myosuit assistance, relative to baseline 2minWT distance measured without the Myosuit in training 0. Instead of the second 10MWT in training sessions 1 to 4, the last three participants performed a 2minWT during each training session

Fig. 4

a Mean daily step count was moderately positively correlated with the observed change in 10MWT walking speed. The number of daily steps was recorded with a wrist-worn step counter during daily activities between training sessions. b The participants’ age was moderately negatively correlated with the observed change in 10MWT walking speed. P3 (green triangle) showed the largest increase in 10MWT speed, was the most active during daily life, and the youngest of all participants