Post-Stroke Upper Limb Function Not Improved With Robot-Assisted Training

A robot-assisted training program using the Massachusetts Institute of Technology Manus robotic gym and enhanced upper limb therapy did not improve upper limb function when compared with usual care for moderate or severe upper limb functional limitation after stroke, according to a study published in The Lancet.

In the robot-assisted training for the upper limb after stroke (RATULS) multicenter, randomized controlled trial, participants aged ≥18 years (n=770) were enrolled between April 14, 2014, and April 30, 2018, to establish whether robot-assisted training improved upper limb function after stroke compared with enhanced upper limb therapy and usual care alone. Randomization was done through a central, independent, web-based service according to center, time since stroke, and severity of upper limb functional limitation (Action Research Arm Test score).

Participants were randomly assigned 1:1:1 to receive robot-assisted training (n=257), an enhanced upper limb therapy program (n=259), or usual care using permuted block sequences (n=254). The same frequency and duration of 45 minutes, 3 times per week for 12 weeks was used to deliver robot-assisted training and enhanced upper limb therapy programs. Patients assigned to the usual care group received a minimum of 45 minutes of each appropriate therapy required for a minimum of 5 days per week, according to the English national quality standard.

The primary outcome measure, upper limb function success as defined using Action Research Arm Test at 3 months after randomization, was achieved by 44% of patients in the robot-assisted training group (n=103/232), 50% of patients in the enhanced upper limb therapy group (n=118/234), and 42% of patients in the usual care group (n=85/203). Action Research Arm Test success was not significantly different between robot-assisted training vs enhanced upper limb therapy (adjusted odds ratio 0.78; 98.3% CI, 0.48-1.27), or usual care (adjusted odds ratio 1.17; 98.3% CI, 0.70-1.96). There was no significant difference between enhanced upper limb therapy and usual care (adjusted odds ratio 1.51; 98.3% CI, 0.90-2.51). Upper limb function success at 6 months was achieved by 47% in the robot-assisted training group (n=103/221), 54% in the enhanced upper limb therapy group (n=118/218), and 44% in the usual care group (n=81/185).

Limitations of this study include potential bias arising from differential attrition rates between the usual care group and robot-assisted training and enhanced upper limb therapy group. Additionally, further validation is needed for the primary outcome derived from Action Research Arm Test, developed specifically for the RATULS trial.

The researchers conclude these findings confirm the conclusions of the 2016 Cochrane review of 33 trials, which found repetitive functional task practice improved arm function, activities of daily living, and hand function. However, the RATULUS trial found no evidence that a robot-assisted training program significantly improved upper limb function or activities of daily living after stroke. More therapy might result in better outcomes as shown in prior studies, but adequately powered dose-finding studies of interventions tailored to targeted subgroups are needed. Future trials should consider a patient-reported outcome measure.

Several authors acknowledge conflicts of interest. Please see reference for a full list of disclosures.

Reference

Rodgers H, Bosomworth H, Krebs HI, et al. Robot assisted training for the upper limb after stroke (RATULS): a multicentre randomised controlled trial [published online May 22, 2019]. Lancet. doi: 10.1016/S0140-6736(19)31055-4