Differences in fatigue and cardiorespiratory parameters during walking with and without robot-assistance: a systematic review

Background: In recent years, studies on rehabilitation robotics for patients with reduced ambulatory skills, have been on the rise. However, to our knowledge, there is no systematic overview of the effects on fatigue and cardiorespiratory parameters yet. Objective: The aim of the present systematic review is to summarize the effects of walking with robot-assistance compared to walking without robot-assistance on fatigue and cardiorespiratory parameters. Methods: In February 2015, electronic databases PubMed and Web of Science, were searched. Trials were included if the effects of robot-driven walking on fatigue or cardiorespiratory parameters were compared to unassisted gait or walking with any form of unpowered assistance. Methodological quality was rated independently by two researchers. Results: After eligibility assessment, 13 studies, concerning 126 participants (68 healthy subjects, 39 stroke patients and 19 patients with spinal cord injury), were included. The ‘Lokomat’, the ‘Gait Trainer’ and a powered bilateral ankle-foot exoskeleton were the most frequently used robotic devices. All studies except one, comparing powered versus unpowered exoskeletons, reported significant lower metabolic cost, heart rate and VO2 in the powered condition, for both patients and healthy subjects. Also, trials comparing robot-driven gait to unassisted or manual assisted gait, reported in general significant lower VO2 and heart rate during robot-assistance. Studies regarding robot- versus passive orthosis-assistance were insufficient and heterogeneous. Conclusion: In general, these results suggest that robot-assisted walking is less energy demanding and cardiorespiratory stressful than unpowered or unassisted gait. Additional research with more homogenous studies are needed to draw firm conclusions.