The aim of this commentary was to discuss, from a rehabilitation perspective, the recently published Cochrane Review of “Electromechanical and robot-assisted arm training for improving activities of daily living, arm function, and arm muscle strength after stroke” by Mehrholz et al.1 (https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD006876.pub5/full), under the direct supervision of Cochrane Stroke. This Cochrane Corner is produced in agreement with the American Journal of Physical Medicine & Rehabilitation by Cochrane Rehabilitation.
More than two thirds of people who have had a stroke have difficulties with reduced arm function, which can restrict a person's ability to perform everyday activities, reduce productivity, limit social activities, and lead to economic burden. Electromechanical and robot-assisted arm training uses specialized machines to assist rehabilitation in supporting shoulder, elbow, or hand movements. However, the role of electromechanical and robot-assisted arm training for improving arm function after stroke is unclear.
ELECTROMECHANICAL AND ROBOT-ASSISTED ARM TRAINING FOR IMPROVING ACTIVITIES OF DAILY LIVING, ARM FUNCTION, AND ARM MUSCLE STRENGTH AFTER STROKE
What Was the Aim of this Cochrane Review?
The aim of this Cochrane Review was to assess the effects of electromechanical and robot-assisted arm training for improving arm function in people who have had a stroke.
What Was Studied in the Cochrane Review?
The population addressed in this review was people with stroke without severe comorbidities; the interventions studied were electromechanical and robot-assisted arm training for recovery of arm function.
The intervention was compared with other rehabilitation or placebo interventions or no treatment. The outcomes studied were activities of daily living in people after stroke as well as arm function and muscle strength of the affected arm.
Up-to-dateness of the Cochrane Review
The review authors searched for studies that had been published up to January 2018.
What Are the Main Results of the Cochrane Review?
The review included 45 studies.
The review shows that electromechanical and robot-assisted arm training:
- improved activities of daily living scores (standardised mean difference [SMD] = 0.31, 95% confidence interval = 0.09 to 0.52, P = 0.0005; I 2 = 59%; 24 studies, 957 participants, high-quality evidence);
- improved arm function (SMD = 0.32, 95% confidence interval = 0.18 to 0.46, P < 0.0001, I 2 = 36%, 41 studies, 1452 participants, high-quality evidence);
- improved arm muscle strength (SMD = 0.46, 95% confidence interval = 0.16 to 0.77, P = 0.003, I 2 = 76%, 23 studies, 826 participants, high-quality evidence);
- did not increase the risk of participant dropout (risk difference = 0.00, 95% confidence interval = −0.02 to 0.02, P = 0.93, I 2 = 0%, 45 studies, 1619 participants, high-quality evidence) and adverse events were rare.
How Did the Authors Conclude on the Evidence?
The review authors concluded that people who receive electromechanical and robot-assisted arm training after stroke might improve their activities of daily living, arm function, and arm muscle strength. However, the results must be interpreted with caution because, although the quality of the evidence was high, there were variations between the trials in the intensity, duration and amount of training, type of treatment, participant characteristics, and measurements used.
What Are the Implications of the Cochrane Evidence for Practice in Rehabilitation?
We found that people after stroke who receive electromechanical or robot-assisted arm training are more likely to show statistically significant improvements in their activities of daily living, arm function, and muscle strength of the paretic arm, and we rated the quality of evidence as high.
In practice, electromechanical or robot-assisted arm training could increase the intensity of arm therapy. It is possible that more repetitions during the same therapy time could be achieved with the support of electromechanical and robot-assisted therapy. Electromechanical devices could, therefore, be a useful adjunct to conventional therapies.
However, the observed treatment effects were relatively small. Therefore, it is still not clear whether the difference between electromechanical or robot-assisted arm training and other interventions is clinically meaningful for most people after stroke. A dilemma therefore remains for clinicians. On the one hand, there is high certainty that use of a robot as part of arm rehabilitation improves outcomes, but on the other hand, the effects may be less than those hoped for and needed by patients and therapists.
Despite the continued uncertainty, this is an important review, because it demonstrates that high-quality evidence exists for the use of electromechanical and robot-assisted arm training for stroke rehabilitation. The judgment of evidence as high quality means that the authors are confident in the results and that further research would be unlikely to change the direction or size of these findings.
Several research questions remain outstanding and further research is needed to help maximize the use of electromechanical and robot-assisted arm training for stroke rehabilitation.
First, it is unclear whether these devices are particularly suitable or effective for specific subgroups of patients. This question was explored within the review, with evidence from one subgroup analysis showing that the greatest effects may occur in patients who are less than 3-mo poststroke.
Second, there is limited evidence on the relative effectiveness of different types of arm training modalities. Should training focus on proximal or distal joints? Is it best to practice tasks bilaterally or unilaterally?
An additional limitation of the current evidence in this field is that patients with comorbidities such as aphasia, apraxia, or cognitive deficits are often excluded from research studies. This means that the evidence reviewed here may not directly apply to the patients that we often observe in clinical practice, who commonly have a wide variety of other stroke related problems.
Future studies should also include patients with significant comorbidities, reflecting the patients who are commonly seen in “real-world” rehabilitation facilities.
Future research remains necessary to explore the impact of different types of training modalities (as described previously) as well as the relative effects of different types of robotic arm training devices. There is currently no head-to-head comparison of different arm training devices/machines, and such a comparison is important to appropriately inform decisions about the purchase of equipment for use within rehabilitation settings.
Potential future steps to generate evidence relating to the relative effects of different devices may include high-quality network meta-analyses, meta-analyses with individual patient data, or primary research studies that directly compare different devices or device approaches.
Lastly, with an increasing emphasis on cost-efficiencies and the delivery of cost-effective interventions, it is important that future research incorporates appropriate economic and cost-benefit analyses.
The author thanks Cochrane Rehabilitation and Dr. Alex Pollock at Cochrane Stroke for reviewing the contents of the Cochrane Corner.