Optimization of Gait Assistance Pattern for Charcot-Marie-Tooth Patients Based on Forward Predictive Simulation

Muscle weakness of Charcot-Marie-Tooth (CMT) patients makes their gaits abnormal. Powered orthoses are expected to adjust the gaits, save metabolic energy and reduce the risk of falling. However, there is no guidance for the assistance pattern for CMT patients. Therefore, we optimized the gait assistance pattern using forward predictive simulation framework based on musculoskeletal model. First, we modified plantar flexor and dorsiflexor parameters of the model to simulate pathological gaits. Then, we applied ideal ankle plantarflexion & dorsiflexion, ankle plantarflexion, ankle dorsiflexion, knee flexion & extension, and hip flexion & extension assistance torques to the model. The pathological gait data collected by simulation and experiment were compared. The mean of metabolic rate, root mean square of muscle activations, and ankle angles with the different assistance patterns were analyzed. Results showed that the simulated gait can capture the characteristics of the pathological gait and ankle plantarflexion & dorsiflexion assistance with a plateau was the optimal assistance pattern. This provides a guidance for gait assistance in CMT patients.