Voluntary Muscle Contraction Pattern in Cerebral Palsy by Reducing Guidance Force in Robot-Assisted Gait Training: A Proof of Concept Focused on a Single-Participant Study

This study aimed to investigate if voluntary participation in robot-assisted gait training leads to more concentrated muscle activity patterns and clinical measure improvements. A single-participant research design study was conducted with a gradual reduction in robotic assistance during robot-assisted gait training. A child with cerebral palsy participated in 20 robot-assisted gait training sessions and two assessment sessions across 99 days. The assistive force of the Lokomat gradually reduced during repeated training. The effects of reduced assistive force on muscle activity patterns were quantitatively analyzed using a clustering algorithm and electromyography. Improvements in overall gait quality and muscle strength were measured after robot-assisted gait training. The results also showed that the number of clustered representative patterns doubled and muscle activation patterns increased when the assistance decreased by 20%, whereas full robot assistance might have hindered active participation. Since assistive force modulation can be a key in robotic rehabilitation, the proposed protocol, involving gradual assistive force reduction, demonstrates promising efficacy and allows for in-depth analysis. Therefore, further randomized clinical trials based on this study can be possible for children with cerebral palsy.