Biofeedback Gait Retraining for Stiff Knee Gait Correction

The research team has developed a visual kinematic biofeedback system which is designed to help children with hemiplegic cerebral palsy (CP) correct a pattern of reduced knee extension in terminal swing and early stance. The system provides real-time feedback on the knee angle pattern during walking on a treadmill. From a pilot study on children with CP, the investigators observed that when the system was used in children who have stiff knee gait (SKG), training with knee feedback alone could lead to an increase in hip flexion which in turn led to limited normalization of the knee pattern through the whole gait cycle. This study, funded by the NIDILRR Switzer grant (PI: X Liu, Ph.D.), seeks to address the question of whether a training design with feedback on both the knee and hip joints would reduce this tendency to generate unintended changes in hip joint motion, and in doing so also improve convergence to the intended knee joint pattern. This study will test ten children and young adults with brain injury who have SKG and examine their short term adaptations to two types of kinematic feedback training: feedback training on the knee alone (condition B) and sequential switched feedback training on the knee and the hip (condition A). An additional sensor placed on the pelvis will be added to the current feedback system for measurement and feedback on the hip joint angle. Software enhancements will also be made with methods that will allow study and description of adaptations in measures of inter-limb symmetry during training. The participants will visit twice with a 2-week washout period between the two visits. Five participants will first undergo condition B in the first visit and then condition A in the second visit, while the other five participants will start with condition A in the first visit and then undergo condition B in the second visit. To compare the effects of the conditions on normalizing the joint angle trajectories, the knee and hip kinematics will be collected and analyzed in both the conditions. To investigate the coordination of lower limb segments under feedback training, relative phase measures will be analyzed on the hip and the knee. To examine whether participants adapt to the feedback retraining in terms of improvement in gait quality, symmetry ratios will be analyzed.