RATULS: No Advantage for Robotic Assist in Post-Stroke Rehab

Damian McNamara

May 24, 2019

MILAN — Despite the promise of robot-assisted rehabilitation to help people recovering from stroke — particularly those who could benefit from a series of repetitive upper limb movements over time — the largest study to date shows use of the robot did not significantly improve functional outcomes compared with enhanced physical therapy or usual care.

A total 44% of stroke survivors randomly assigned to robot-assisted training successfully improved upper limb function, compared with 50% of people in an enhanced upper limb therapy (EULT) and 42% of those assigned to usual care. This primary outcome was based on score improvements on the Action Research Arm Test (ARAT) compared with baseline.

"We had no significant difference in our outcomes at 3 months," Helen Rodgers, MD, clinical professor of stroke care at Newcastle University in the United Kingdom and an investigator for the Stroke Research Group at the Institute of Neuroscience at Newcastle, said during a press briefing here at the 5th European Stroke Organisation Conference (ESOC) 2019.

Some of the previous research suggested a benefit, "so I was quite surprised and disappointed. We do have a number of statistical differences but we don't think these are clinically meaningful," Rodgers told Medscape Medical News. "We have seen an improvement in ADL (activities of daily living), which is good."

"Robot-assisted training using the MIT-Manus Robotic Gym system did not improve upper limb function when compared to enhanced upper limb therapy or usual care," she said.

These and other findings of the Robot Assisted Training for the Upper Limb after Stroke (RATULS) trial were simultaneously published online May 22 in The Lancet.

Addressing a Clinical Question

Loss of arm function is a common problem after stroke, Rodgers noted. "We are not quite sure how best to provide therapy…but we have evidence that repetitive training is important," she said. "Robots can perform tasks in a highly consistent and controlled manner compared to a therapist."

Multiple Cochrane reviews have examined robot-assisted therapy for stroke survivors with mixed results. The heterogeneity of participants and limited number of people in individual studies limits the interpretation. "The largest trial to date had 120 participants," she added.

To learn more, Rodgers and colleagues evaluated 770 adult stroke survivors. They randomly assigned 257 to receive robot-assisted training, 259 to the EULT protocol, and 254 others to usual care. Participants were recruited at four study centers in the UK between April 2014 and April 2018. Approximately 60% were men, the average age was early 60s, and participants scored a mean 8.6 on the ARAT at baseline, indicating moderate-to-severe arm impairment.

The mean time between stroke and study randomization was 240 days (8 months).

The participants in the robot-assisted and EULT groups attended 45-minute face-to-face therapy sessions, three times per week for 12 weeks. The same therapists and therapy assistants provided care in these different settings. People in the usual care group received usual National Health Service care at their local clinic.

Compared to usual care, robot-assisted training did not improve upper limb function, with an adjusted odds ratio [aOR] of 1.17 (98.3% confidence interval [CI], 0.70 - 1.96). Similarly, EULT also did not improve upper limb function compared to usual care (aOR, 1.51; 98.3% CI, 0.90 - 2.51).

When comparing the effects of robot-assisted training and EULT, again there was no significant improvement observed (aOR, 0.78; 98.3% CI, 0.48 - 1.27).

At 6 months, success based on ARAT score improvement from baseline was observed in 47% of robot-assisted participants, 54% of the EULT group and 44% of the usual care patients. This secondary outcome was not statistically significant.

Impairment Improved

Despite not meeting the study's primary endpoint, "We have some interesting and important secondary outcomes," Rodgers said.

Measures of impairment, for example, showed a benefit in terms of robot-assisted therapy and enhanced upper limb therapy over usual care. The Fugl–Meyer Assessment (FMA) motor score results were statistically and clinically superior at 3 months favoring robot-assisted therapy and EULT vs usual care.

"However, the only remaining significant difference at 6 months favored the robot assisted group over the usual care patients," Rodgers said.

The investigators used the Barthel ADL Index to assess activities of daily living. However, she said, "We have decided this result is not clinically important at 3 or 6 months."

They also evaluated activities of daily living on the Stroke Impact Scale, "The enhanced group did better than robot-assisted group or usual care at 3 months, with a result that was both statistically and clinically significant," she said. There was no significant difference at 6 months, however.

When the investigators evaluated hand function on the Stroke Impact Scale, the robot-assisted therapy was not associated with any significant benefit compared to the other two approaches.

Improvements in mobility favored only EULT over usual care at 3 months, but the significant difference did not persist at 6 months.

"The results of the RATULS trial do not support the routine use of robot-assisted training (MIT-Manus robotic gym) for patients with moderate or severe upper limb functional limitation resulting from stroke," the authors conclude in The Lancet publication.

"Further research is needed to find ways to translate the improvements in upper limb impairment seen with robot-assisted training into improvements in upper limb function and ADL," they add. "This might involve combining robot-assisted training with more functionally orientated therapy strategies."

Secondary Outcomes Small

Robot-assisted training did not improve upper limb function vs usual care (aOR, 1.17; 98.3% CI, 0.70 - 1.96) or vs matched-dose EULT (aOR, 0.78; 98.3% CI, 0.48 - 1.27), Julie Bernhardt and Jan Mehrholz write in an accompanying editorial in The Lancet. Nor did usual care differ from EULT (aOR, 1.51; 98.3% CI, 0.90 - 2.51).

"Although some secondary outcome analyses favoured higher-dose training (EULT or robot-assisted training) over usual care, the effects were small," they add. Bernhardt is affiliated with the National Health and Medical Research Council, Centre of Research Excellence in Stroke Rehabilitation and Brain Recovery at the University of Melbourne in Australia. Mehrholz is with the Department of Public Health, Faculty of Medicine Carl Gustav Carus, Technical University Dresden in Germany.

"A further point to consider is the time to the start of training after stroke. In RATULS, the median time from stroke to baseline was 240 days [interquartile range, 109–549]," they add.

More than 10 devices are available for robot-assisted arm therapy. "RATULS shows that large, well conducted, multisite trials using one of these devices is possible — learning from this and getting the fundamentals right for future trials is imperative to advance the field," the editorialists note.

The National Institutes of Health Research Health Technology Assessment programme funded this study. Rodgers, Bernhardt, and Mehrholz have disclosed no relevant financial relationships.

5th European Stroke Organisation Conference (ESOC) 2019: Study presented May 22, 2019. Full text

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