Researchers examine impact of level of robotic assistance on upper extremity rehabilitation of stroke survivors

April 4, 2022 — Researchers from the Department of Occupational Therapy, College of Health and Human Sciences, Osaka Prefectural University in Japan conducted exploratory research to examine the impact of the level of robotic assistance on rehabilitation of the upper limbs of stroke survivors. Motor recovery of the upper limb is always a great challenge for rehabilitation professionals and also for the patient. In the past, there were so many theories proposed by many stroke management pioneers, but many of them failed and functional rehabilitation is currently found to be the most effective in upper limb rehabilitation because it emphasizes task-specific training and practice-based learning.

Advances in technology like robotics have made the therapist’s job easier, helping patients do guided limb movements and practicing them with more repetition. However, there is a conflicting opinion regarding the ideal level of support for a better prognosis. This is evident when Takashi Takebayashi and colleagues mention that “robotic therapy may produce better upper extremity recovery compared to conventional rehabilitation remains unclear”

To address this controversy, a retrospective sub-analysis of a previous study was conducted. Takashi Takebayashi and colleagues selected an experimental study performed with 60 participants selected from 715 stroke patients of a wide age range using specific selection criteria, at six rehabilitation hospitals in Japan, from November 2008 to April 2010. The researchers randomly assigned the selected patients. into two groups, one receiving maximally guided robotic therapy and the other minimally assisted self-guided robotic exercises. In addition to collecting a detailed history of each patient, performance-based impairment; upper limb motor functions and temporal upper limb performance were also measured using standard outcome measures before and after 6 weeks of intervention.

Previous research has suggested that maximum assistance using robotics can impede voluntary efforts generated by patients and therefore the level of assistance should be within a tailored limit. As this claim is also contradicted by a few scholars, Takashi Takebayashi and his colleagues wanted to solve the riddle. Thus, they categorized the patients into high robotic assistance and low robotic assistance, based on the amount of external support and guidance offered by the robot.

Both groups underwent the intervention for a period of 6 weeks and to avoid bias, a specialist person, who was blinded to the study, was used to conduct all outcome parameters. The subjects were divided into several groups among which the severity of the stroke manifestation was predominant. The subjects were divided into mild to moderate groups and moderate to severe groups to understand if there was a difference in the contribution of robotics between them.

The results of their study demonstrated that the intervention group comprising stroke survivors with severe to moderate stroke severity (FMA < 30) showed significantly better improvement in EU function and performance than the control group with the same severity. Interestingly, stroke survivors with moderate to mild stroke severity (FMA ≥ 30) in the control group showed significantly better improvement using the same outcome tools compared to the intervention group.

The researchers cited study findings that “to maximize improvements in affected UE function in subacute stroke survivors, robotic assistance may need to be increased in patients with severe-to-moderate and diminished paralysis in patients with moderate to moderate paralysis”. – a slight paralysis, to improve the performance of voluntary movements as much as possible”. Therefore, research has highlighted that the selection of the level of intensity and the level of assistance offered by robotics is highly technical and professional, and therefore the use of robotics requires more expertise and patient assessment. The researchers also shed light on the varied results produced by end-effector and exoskeleton type robotics, however, the researcher used the end-effector type of robotics for his research and produced this new result.

The researchers build on previous studies that have stated that robotics can enhance sensorimotor cortex activation during the intervention period and thus significantly improve motor performance. The authors hypothesize that the changes that occurred among the participants could be due to Hebbian plasticity. That said, the researcher also advises future findings to focus on proving the same using more objective tools like functional magnetic resonance imaging using larger samples.

In summary, the researchers clearly stated that “an optimal amount of robotic assistance has been shown to be the key to maximizing improvement in post-stroke UE paralysis”

The article “Impact of level of robotic assistance on upper extremity function in stroke patients undergoing ancillary robotic rehabilitation: sub-analysis of a randomized clinical trial” was published in Journal of Neuroengineering and Rehabilitation at


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