For patients who have had a stroke, powered robotic exoskeletons are a potential intervention for gait rehabilitation to enable repetitive walking practice, which maximizes neural recovery. As this is a relatively new technology for stroke, a pair of researchers from Canada conducted a scoping review to help guide current research and propose recommendations for advancing the research development. The aim of the review was to map the current literature surrounding the use of robotic exoskeletons for gait rehabilitation in adults post-stroke. The article was published online June 8, in the open-access Journal of NeuroEngineering and Rehabilitation.
Five databases (Pubmed, OVID MEDLINE, CINAHL, Embase, and Cochrane Central Register of Clinical Trials) were searched for articles from inception to October 2015; non-English studies were excluded, which could have had a limiting effect on the conclusion of the review, the authors said. Reference lists of included articles were reviewed to identify additional studies. Articles were included if they utilized a robotic exoskeleton as a gait training intervention for adult stroke survivors and reported walking outcome measures.
Of 441 records identified, 11 studies published within the last five years that involved a total of 216 participants met the inclusion criteria. The study designs ranged from pre-post clinical studies (n = 7) to controlled trials (n = 4); five of the studies utilized a robotic exoskeleton device unilaterally, while six used a bilateral design. There were four different powered exoskeletons utilized within the included studies, ranging from unilateral, single joint devices to bilateral, multijoint robotics with the capacity to detect volitional bioelectrical signals to initiate powered movement: H2 (joints actuated: hip, knee, and ankle; SMA (joints actuated: hip); HAL (joints actuated: hip and knee); and AlterG (joints actuated: knee). The participants’ conditions ranged from sub-acute (< 7 weeks) to chronic (> 6 months) stroke. Training periods ranged from a single-session to eight-week interventions. The main walking outcome measures were gait speed, the Timed Up and Go test, the six-minute walk test, and the Functional Ambulation Category.
Meaningful improvement with exoskeleton-based gait training was more apparent in patients who had a sub-acute stroke compared to chronic stroke. Two of the four controlled trials showed no greater improvement in any walking outcomes compared to a control group in chronic stroke. Given this, the authors concluded that clinical trials demonstrate that powered robotic exoskeletons can be used safely as a gait training intervention for stroke. Preliminary findings suggest that exoskeletal gait training is equivalent to traditional therapy for patients who had chronic stroke conditions, while patients who had sub-acute strokes may experience added benefit from exoskeletal gait training. Efforts should be invested in designing rigorous, appropriately powered controlled trials before powered exoskeletons can be translated into a clinical tool for gait rehabilitation post-stroke.
The authors proposed several questions for future research:
- Do non-ambulatory chronic stroke participants experience the same improvement in walking ability as sub-acute stroke participants when using an exoskeleton device for gait retraining?
- How does initial functional presentation impact the nature of improvement in walking ability when using an exoskeleton device for gait rehabilitation?
- What is the impact of different exoskeletons (number of joints actuated, level of assistance, and control of stepping) on gait rehabilitation in stroke?
- What is the impact of using a bilateral design compared to a unilateral design for gait rehabilitation in hemiparetic stroke?
- What is the optimal dose of exoskeletal gait training for stroke patients to regain the most walking ability?
- How does overground exoskeletal gait training compare to body weight-supported treadmill training?
- Can exoskeletons be used to safely ambulate two-person assist patients early after stroke with minimal injury risk to therapists?