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Kawasaki S1, Ohata K1, Watanabe S1, Nogi S1, Hirabayashi Y2, Yoshida T3, Yokoyama A3
1Kyoto University Graduate School of Medicine, Department of Human Health Sciences, Kyoto, Japan, 2HONDA R&D CenterX Co.,Ltd., Wako, Japan, 3Kyoto University Hospital, Kyoto, Japan
Background: Muscle synergy reflects the complexity of the central nerve system during movements. Many studies have reported that children with cerebral palsy (CP) use fewer synergies than typically developed children while walking. Recently, rehabilitation robots are expected to improve gait function in children with CP. Honda Walking Assist (HWA) is a wearable robot that helps the flexion and extension of both limbs during gait. However, it is not clear if assisting the limb movements by HWA could induce the change in muscle synergies.
Purpose: The purpose of this study was to clarify the change of muscle synergy in children with CP by assisting the limb movements using HWA.
Methods: Ten children with cerebral palsy (mean age 11.1±2.3years, GMFCS I/II/III 2/5/3) from Kyoto University were randomly grouped into 2 groups and performed the walking trials for 2 days. This study was approved by the ethics committee of Kyoto University Graduate School and Faculty of Medicine. HWA used in this study was adjusted to fit the children's body. In both groups, participants first performed 5.5 meter-overground walk (OG-pre) and two 30-second treadmill walking trials with no assistive torque (0N-pre) by HWA. Then participants randomly performed ten 30-second walking tests with either assistive torque (A trial) or no assistive torque (NA trial) in the first day, and another in the second day. After A or NA trial, five 30-second treadmill walking trials with no assistive torque (0N-post) and 5.5 meter-overground walk (OG-post) were performed .In all measurement, surface electromyographic (EMG) activity and kinematic data were measured. EMG of 5 muscles (rectus femoris, semitendinosus, tibial anterior, lateral gastrocnemius, soleus) were collected by Delsys Trigno Wireless System from both limbs. Kinematic data were measured by IMU-based motion capture system (Xsens MVN BIOMECH Awinda). In OG trial, walking speed and number of steps were measured. Nonnegative matrix factorization algorithm was used to calculate the number of muscle synergies. Repeated three-way ANOVA was used to compare the change of muscle synergy between A trial and NA trial. Bonferroni correction was used to adjust the significant values.
Results: Each limb was grouped into less-affected side and more-affected side due to the range of the hip motion. The number of muscle synergies increased only on the more-affected side and while walking with assistive torque by HWA (p 0.05). However, walking speed did not change between OG-pre and OG-post trials.
Conclusion(s): The number of muscle synergies on the more-affected side increased by assisting the limb movements by HWA in children with CP. Rehabilitation robot might have the potential to change the behavior of the central nerve system in cerebral palsy.
Implications: This study proposes the rehabilitation approach for increasing the number of muscle synergies in children with cerebral palsy.
Keywords: robot, cerebral palsy, synergy
Funding acknowledgements: This study was supported by Honda R&D Center X Co.,Ltd.
Purpose: The purpose of this study was to clarify the change of muscle synergy in children with CP by assisting the limb movements using HWA.
Methods: Ten children with cerebral palsy (mean age 11.1±2.3years, GMFCS I/II/III 2/5/3) from Kyoto University were randomly grouped into 2 groups and performed the walking trials for 2 days. This study was approved by the ethics committee of Kyoto University Graduate School and Faculty of Medicine. HWA used in this study was adjusted to fit the children's body. In both groups, participants first performed 5.5 meter-overground walk (OG-pre) and two 30-second treadmill walking trials with no assistive torque (0N-pre) by HWA. Then participants randomly performed ten 30-second walking tests with either assistive torque (A trial) or no assistive torque (NA trial) in the first day, and another in the second day. After A or NA trial, five 30-second treadmill walking trials with no assistive torque (0N-post) and 5.5 meter-overground walk (OG-post) were performed .In all measurement, surface electromyographic (EMG) activity and kinematic data were measured. EMG of 5 muscles (rectus femoris, semitendinosus, tibial anterior, lateral gastrocnemius, soleus) were collected by Delsys Trigno Wireless System from both limbs. Kinematic data were measured by IMU-based motion capture system (Xsens MVN BIOMECH Awinda). In OG trial, walking speed and number of steps were measured. Nonnegative matrix factorization algorithm was used to calculate the number of muscle synergies. Repeated three-way ANOVA was used to compare the change of muscle synergy between A trial and NA trial. Bonferroni correction was used to adjust the significant values.
Results: Each limb was grouped into less-affected side and more-affected side due to the range of the hip motion. The number of muscle synergies increased only on the more-affected side and while walking with assistive torque by HWA (p 0.05). However, walking speed did not change between OG-pre and OG-post trials.
Conclusion(s): The number of muscle synergies on the more-affected side increased by assisting the limb movements by HWA in children with CP. Rehabilitation robot might have the potential to change the behavior of the central nerve system in cerebral palsy.
Implications: This study proposes the rehabilitation approach for increasing the number of muscle synergies in children with cerebral palsy.
Keywords: robot, cerebral palsy, synergy
Funding acknowledgements: This study was supported by Honda R&D Center X Co.,Ltd.
Topic: Robotics & technology; Paediatrics: cerebral palsy; Neurology
Ethics approval required: Yes
Institution: Kyoto University Graduate School and faculty of medicine
Ethics committee: Kyoto University Hospital Ethics Committee
Ethics number: C1313
All authors, affiliations and abstracts have been published as submitted.
