A Parametric Investigation of Swing Motion Triggered by Electrical Stimulation in Paraplegic Patients Using Response Surface Method

We identified torque response of flexion reflex associated with hip angle and angular velocity in 6 subjects with chronic SCI and developed two dimensional dynamic model with three segments, thigh, shank and foot. Influences of stimulation parameters such as amplitude, frequency and duration time of pulse train for producing swing motion of lower limb were investigated with response surface method to obtain optimal solutions. The initial hip flexion velocity (F-value > 19.0) and knee flexion velocity (F-value > 9.0) were clearly significant, while the initial hip angle was indistinguishable from the estimated amount of error. When the limb motion was simulated with initial hip and knee flexion velocity, the stimulation amplitude was increased 53%, the frequency was decreased 37% and the duration time was decreased 33% with respect to no initial condition