4. Discussion
chronic stroke, spasticity
The present study compared exoskeletal robot-assisted upper limb rehabilitation with conventional upper limb ergometer physiotherapy and demonstrated that HEXO-UR30A was also effective for chronic stroke patients. The upper limb motor function of patients improved in both groups; however, the function of active daily living did not improve in both groups.In a previous study, Lynch et alOur findings demonstrated that the motor function of chronic patients who received physiotherapy with exoskeletal robot-assisted continuous passive movement significantly improved. Lindberg et alHEXO-UR30A training targets specifically the shoulder, and it seems that it improves motor control of the shoulder compared to the conventional ergometer training. Sub-analysis showed shoulder Fugl–Meyer assessment (FMA) improved significantly in the HEXO group but not in the control group. A meta-analysis reported that shoulder/elbow robotics showed significant effects on FMA and FMA-shoulder/elbow/coordination subscale. The difference in FMA-shoulder/elbow/coordination subscale was about 5% in the total score of 2.15 points.The shoulder range of motion improved in both the control and HEXO groups. This could be because HEXO-UR30A sets the range of motion to the point where patients can move painlessly and comfortably, unlike the control group where patients move their shoulders according to the ergometer arm pedal height, which is set at 60 degrees. Although the median passive and active range of motion of shoulder flexion in the control group is higher than 60 degrees, there were patients whose range of motion was less than 60 degrees. Passively stretching the shoulder more than what patients can move might lead to an increase in the shoulder range of motion. Brokaw et alLimitations of this study include a small sample size because of which the statistical power might be low. Future studies with a larger sample size will be warranted. Moreover, the participants who were enrolled in this study were generally good in the function of daily activity where the median modified Barthel index was over 90. This may explain why there was no significant improvement in ADL. There is a plateau in function recovery, and better function at a high-demanding skill is more difficult to achieve. Finally, the investigator who evaluated the patients was not blinded to patients group allocation, and this might affect the measurement. Further studies where the investigator is blinded to group allocation are warranted.In conclusion, the novel HEXO-UR30A can be effective in the improvement of shoulder motor functions in chronic stroke patients. The daily activity function, spasticity, and range of motion did not improve in both the HEXO and control groups. Patients who received HEXO-UR30A assisted rehabilitation reported high satisfaction, which might improve patient involvement in upper limb rehabilitation.