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NIHR Signal Robot-assisted training offers little useful improvement in severe arm weakness and function after stroke

Published on 6 August 2019

doi: 10.3310/signal-000802

People who have severe arm weakness following stroke have no better function after robot-assisted training or enhanced upper limb therapy than those who have usual NHS care.

This large multicentre trial, funded by the NIHR, randomised 770 adult stroke patients to robot-assisted training using the MIT-Manus robotic gym, to an enhanced therapy programme or to usual NHS care. All three groups had improved arm function after three months, with no significant differences between the groups.

The robust design succeeded in correcting some biases of previous trials in this area, though ‘usual NHS care’ may not have been uniform for all patients in the comparison group.

These results suggest that widespread use of robot-assisted training is unlikely to benefit stroke patients, although there may still be subgroups of sufferers who would benefit. This has implications for stroke patients, those delivering rehabilitation services and for commissioners of healthcare services.

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Why was this study needed?

Around 80% of people who have a stroke experience some loss of arm function. This has a distressing and often lasting impact on their quality of life, with everyday tasks such as washing and dressing becoming difficult.

Robot-assisted training can help stroke patients with moderate or severe upper limb impairment perform repetitive tasks. A 2018 Cochrane Review of 45 trials with 1,619 participants, found significantly improved function at the end of training but the studies were generally small and the quality of evidence generally low.

Enhanced therapy programmes focus on repetitive practice of everyday tasks and have been associated with improved arm function in previous smaller studies.

Known as ‘RATULS’ (Robot Assisted Training for the Upper Limb after Stroke), this trial is the largest study of its kind. Its findings should be more reliable because of its size and the harmonisation of treatment protocols, devices and outcomes.

What did this study do?

RATULS was a randomised controlled trial carried out at four NHS centres in the UK between 2014 and 2018. A total of 770 adult stroke patients (average age 61) with moderate or severe upper limb functional limitation, were recruited between one and five years after their first stroke. They received either robot-assisted training using the MIT-Manus robotic gym (257 patients), enhanced therapy (259 patients), or usual NHS care (254 patients).

Robot-assisted training and enhanced therapy were provided for 45 minutes, three times per week for 12 weeks, in addition to usual post-stroke care.

After three months, improvement in participants’ arm function was measured, using the Action Research Arm Test (ARAT), which assesses the ability to perform basic tasks (see Definitions).

This was a robust trial design, and the results should be reliable.

What did it find?

  • Significant improvement on the ARAT scale was achieved by 103 (44%) of 232 patients in the robot-assisted training group, 118 (50%) of 234 in the enhanced therapy group, and 85 (42%) of 203 in the usual care group.
  • Compared with usual care, robot-assisted training did not improve upper limb function (adjusted odds ratio [aOR] 1.17, 98.3% confidence interval [CI] 0.70 to 1.96) nor did enhanced therapy (aOR 1.51, 98.3% CI 0.90 to 2.51).
  • The effects of robot-assisted training did not differ from enhanced therapy (aOR 0.78, 98.3% CI 0.48 to 1.27).
  • In the trial, it was estimated that robot-assisted training cost an average of £5,387 per participant; enhanced therapy cost £4,451 per participant; usual care cost £3,785 per participant. The incremental cost per QALY at six months for the enhanced therapy group compared with the usual care group was £74,100, with a 19% chance of being cost-effective at the usual NHS £20,000 willingness to pay threshold.

What does current guidance say on this issue?

NICE recommends that stroke patients are offered a minimum of 45 minutes of an appropriate therapy for a minimum of five days per week.

If a patient is unable to participate for 45 minutes of therapy, it should still be offered on five days per week, for a shorter time. If more rehabilitation is needed at a later stage, then this should be tailored to the patient’s individual needs.

What are the implications?

The RATULS trial suggests that neither robot-assisted training nor enhanced therapy would be effective if routinely used for stroke patients with moderate or severe weakness of the arm after a stroke. Although robot-assisted training can give measurable improvements in upper limb impairment, translating these into real-life changes in function and improvements in daily activities remains a challenge.

This picture may change if we discover how to target these therapies more effectively to different groups, perhaps those with milder weakness, and when best to use them in the recovery phase of stroke.

These results may help inform guidelines in the rehabilitation of people who have suffered a stroke and may help in funding decisions by healthcare commissioners.

Citation and Funding

Rodgers H, Bosomworth H, Krebs H et al. Robot Assisted Training for the Upper Limb after Stroke (RATULS): a multi-centre randomised controlled trial comparing robot-assisted training; an enhanced upper limb therapy programme; and usual care. Lancet. 2019; May 22. doi:10.1016/S0140-6736(19)31055-4. [Epub ahead of print].

This project was funded by the NIHR Health Technology Assessment Programme (project number 11/26/05).

Bibliography

Mehrholz J, Pohl M, Platz T et al. Electromechanical and robot-assisted arm training for improving activities of daily living, arm function, and arm muscle strength after stroke. Cochrane Database Syst Rev. 2018;(9):CD006876.

NICE. Stroke rehabilitation in adults. CG162. London: National Institute for Health and Care Excellence; 2013.

Why was this study needed?

Around 80% of people who have a stroke experience some loss of arm function. This has a distressing and often lasting impact on their quality of life, with everyday tasks such as washing and dressing becoming difficult.

Robot-assisted training can help stroke patients with moderate or severe upper limb impairment perform repetitive tasks. A 2018 Cochrane Review of 45 trials with 1,619 participants, found significantly improved function at the end of training but the studies were generally small and the quality of evidence generally low.

Enhanced therapy programmes focus on repetitive practice of everyday tasks and have been associated with improved arm function in previous smaller studies.

Known as ‘RATULS’ (Robot Assisted Training for the Upper Limb after Stroke), this trial is the largest study of its kind. Its findings should be more reliable because of its size and the harmonisation of treatment protocols, devices and outcomes.

What did this study do?

RATULS was a randomised controlled trial carried out at four NHS centres in the UK between 2014 and 2018. A total of 770 adult stroke patients (average age 61) with moderate or severe upper limb functional limitation, were recruited between one and five years after their first stroke. They received either robot-assisted training using the MIT-Manus robotic gym (257 patients), enhanced therapy (259 patients), or usual NHS care (254 patients).

Robot-assisted training and enhanced therapy were provided for 45 minutes, three times per week for 12 weeks, in addition to usual post-stroke care.

After three months, improvement in participants’ arm function was measured, using the Action Research Arm Test (ARAT), which assesses the ability to perform basic tasks (see Definitions).

This was a robust trial design, and the results should be reliable.

What did it find?

  • Significant improvement on the ARAT scale was achieved by 103 (44%) of 232 patients in the robot-assisted training group, 118 (50%) of 234 in the enhanced therapy group, and 85 (42%) of 203 in the usual care group.
  • Compared with usual care, robot-assisted training did not improve upper limb function (adjusted odds ratio [aOR] 1.17, 98.3% confidence interval [CI] 0.70 to 1.96) nor did enhanced therapy (aOR 1.51, 98.3% CI 0.90 to 2.51).
  • The effects of robot-assisted training did not differ from enhanced therapy (aOR 0.78, 98.3% CI 0.48 to 1.27).
  • In the trial, it was estimated that robot-assisted training cost an average of £5,387 per participant; enhanced therapy cost £4,451 per participant; usual care cost £3,785 per participant. The incremental cost per QALY at six months for the enhanced therapy group compared with the usual care group was £74,100, with a 19% chance of being cost-effective at the usual NHS £20,000 willingness to pay threshold.

What does current guidance say on this issue?

NICE recommends that stroke patients are offered a minimum of 45 minutes of an appropriate therapy for a minimum of five days per week.

If a patient is unable to participate for 45 minutes of therapy, it should still be offered on five days per week, for a shorter time. If more rehabilitation is needed at a later stage, then this should be tailored to the patient’s individual needs.

What are the implications?

The RATULS trial suggests that neither robot-assisted training nor enhanced therapy would be effective if routinely used for stroke patients with moderate or severe weakness of the arm after a stroke. Although robot-assisted training can give measurable improvements in upper limb impairment, translating these into real-life changes in function and improvements in daily activities remains a challenge.

This picture may change if we discover how to target these therapies more effectively to different groups, perhaps those with milder weakness, and when best to use them in the recovery phase of stroke.

These results may help inform guidelines in the rehabilitation of people who have suffered a stroke and may help in funding decisions by healthcare commissioners.

Citation and Funding

Rodgers H, Bosomworth H, Krebs H et al. Robot Assisted Training for the Upper Limb after Stroke (RATULS): a multi-centre randomised controlled trial comparing robot-assisted training; an enhanced upper limb therapy programme; and usual care. Lancet. 2019; May 22. doi:10.1016/S0140-6736(19)31055-4. [Epub ahead of print].

This project was funded by the NIHR Health Technology Assessment Programme (project number 11/26/05).

Bibliography

Mehrholz J, Pohl M, Platz T et al. Electromechanical and robot-assisted arm training for improving activities of daily living, arm function, and arm muscle strength after stroke. Cochrane Database Syst Rev. 2018;(9):CD006876.

NICE. Stroke rehabilitation in adults. CG162. London: National Institute for Health and Care Excellence; 2013.

Robot Assisted Training for the Upper Limb after Stroke (RATULS): a multi-centre randomised controlled trial comparing robot-assisted training; an enhanced upper limb therapy programme; and usual care.

Published on 22 May 2019

Helen Rodgers, Helen Bosomworth, Hermano I Krebs, Frederike van Wijck, Denise Howel, Nina Wilson, Lydia Aird, Natasha Alvarado, Sreeman Andole, David L Cohen, Jesse Dawson, Cristina Fernandez-Garcia, Tracy Finch, Gary A Ford, Richard Francis, Steven Hogg, Niall Hughes, Christopher I Price, Laura Ternent, Duncan L Turner, Luke Vale, Scott Wilkes and Lisa Shaw.

Lancet The , 2019

Background Loss of arm function is a common problem after stroke. Robot-assisted training might improve arm function and activities of daily living. We compared the clinical effectiveness of robot-assisted training using the MIT-Manus robotic gym with an enhanced upper limb therapy (EULT) programme based on repetitive functional task practice and with usual care. Methods RATULS was a pragmatic, multicentre, randomised controlled trial done at four UK centres. Stroke patients aged at least 18 years with moderate or severe upper limb functional limitation, between 1 week and 5 years after their first stroke, were randomly assigned (1:1:1) to receive robot-assisted training, EULT, or usual care. Robot-assisted training and EULT were provided for 45 min, three times per week for 12 weeks. Randomisation was internet-based using permuted block sequences. Treatment allocation was masked from outcome assessors but not from participants or therapists. The primary outcome was upper limb function success (defined using the Action Research Arm Test [ARAT]) at 3 months. Analyses were done on an intention-to-treat basis. This study is registered with the ISRCTN registry, number ISRCTN69371850. Findings Between April 14, 2014, and April 30, 2018, 770 participants were enrolled and randomly assigned to either robot-assisted training (n=257), EULT (n=259), or usual care (n=254). The primary outcome of ARAT success was achieved by 103 (44%) of 232 patients in the robot-assisted training group, 118 (50%) of 234 in the EULT group, and 85 (42%) of 203 in the usual care group. Compared with usual care, robot-assisted training (adjusted odds ratio [aOR] 1·17 [98·3% CI 0·70–1·96]) and EULT (aOR 1·51 [0·90–2·51]) did not improve upper limb function; the effects of robot-assisted training did not differ from EULT (aOR 0·78 [0·48–1·27]). More participants in the robot-assisted training group (39 [15%] of 257) and EULT group (33 [13%] of 259) had serious adverse events than in the usual care group (20 [8%] of 254), but none were attributable to the intervention. Interpretation Robot-assisted training and EULT did not improve upper limb function after stroke compared with usual care for patients with moderate or severe upper limb functional limitation. These results do not support the use of robot-assisted training as provided in this trial in routine clinical practice. Funding National Institute for Health Research Health Technology Assessment Programme.

ARAT: Action Research Arm Test. This assesses upper limb function by scoring someone’s ability to carry out several functional tasks, in four subgroups: grasp, grip, pinch, and gross movement. Scoring ranges from 0 (no movement) to 57 (normal function). In this study, the definition of success depended on the baseline level of function as follows:

  • ARAT 0 to 7, improvement of 3 or more points
  • ARAT 8 to 13, improvement of 4 or more points
  • ARAT 14 to 19, improvement of 5 or more points
  • ARAT 20 to 39, improvement of 6 or more points

Expert commentary

This trial compared the effectiveness of usual care, enhanced therapy or robot-assisted training in stroke survivors with moderate to severe arm weakness. Over 35% of participants were more than a year since their stroke, and most had severe weakness.

The specific measures of arm function did not show any change across the 6-months of the study. Neither did the more general measures of function, which indicates that participants were unlikely to recover due to the high baseline level of disability and length of time since stroke.

The intervention was an ‘end effector’ robot and this type of device may not be suitable for those with severe arm weakness and should only be considered for use as part of a more comprehensive rehabilitation programme.

Rory J O’Connor, Charterhouse Professor of Rehabilitation Medicine, University of Leeds; Lead Clinician for Rehabilitation, National Demonstration Centre for Rehabilitation, Leeds Teaching Hospitals NHS Trust

The commentator declares no conflicting interests