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.
Participant characteristics This study will recruit 10 participants according to the inclusion and exclusion criteria. System development In order to measure the quantitative change in hip joint angle online, an additional sensor will be placed on the pelvis segment (overlying the sacrum between the posterior superior iliac spines) and added to the current feedback system. Totally four sensors will be used, including the sensors on the pelvis, thigh, shank, and heel. The hip flexion angle will be calculated from pelvis and thigh sensors. The knee flexion angle will be calculated from thigh and shank sensors, while the heel sensor signal is monitored to isolate strides by detecting contact of the foot with the support surface. To help subjects easily recognize which joint the feedback is cueing for, different backgrounds is selected for the feedback interface for the hip joint and knee joint, respectively. Gait patterns will be video recorded in a sagittal view of the lower extremities. In order to test gait asymmetry by symmetry ratio (dividing the smaller value by the larger value between trained and untrained lower limbs), stance phase duration (% gait cycle) from heel strike to toe off will be identified by motion capturing system with reflective markers. Reflective markers will be placed on the ankles and shoes (fifth metatarsal, heel, rearfoot along the line from heel to toe and below the ankle) on both sides to measure the heel down and toe off events. Biofeedback gait retraining protocol Feedback training on the knee alone (Condition B) will include four 6-mins training blocks: 4-mins knee joint feedback-on and 2-mins feedback-off. Sequential switched feedback training on the knee and the hip (Condition A) will include four 6-mins training blocks: 2-mins knee joint feedback-on, 2-mins hip joint feedback-on, and 2-mins feedback-off. Subjects will wear their comfortable footwear and daily used bracing/orthotic devices during the training sessions. Totally four inertial sensors (MTw, Xsens, Netherlands) will be placed separately on the pelvis, anterior thigh, posterior shank and the heel of the paretic lower limb. For calibration purpose, the subject will first stand in his/her natural standing posture and then stand with the knee (weaker side) flexed at 60 degree adding to the knee angle in the natural standing posture. Prior to training, a treadmill walking trial with comfortable speed will be recorded as the baseline trial. After the baseline trial, a 3 minute practice trial will allow interactive demonstration and practice with the goal that the subject has a clear understanding of the task and how to interpret the feedback. In both the two training conditions, subjects will have 3 mins sitting rest between two consecutive blocks to reduce fatigue.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
10
Condition A will include four 6-mins training blocks: 2-mins knee joint feedback-on, 2-mins hip joint feedback-on, and 2-mins feedback-off. Training with feedback on will occur as follows: The subject will walk on the treadmill and try to achieve the target hip and/or knee flexion pattern shown on the feedback interface. Training with feedback off will occur as follows: The subject will walk on the treadmill and try to maintain the pattern without any form of visual or verbal feedback.
Condition B will include four 6-mins training blocks: 4-mins knee joint feedback-on and 2-mins feedback-off. Training with feedback on will occur as follows: The subject will walk on the treadmill and try to achieve the target hip and/or knee flexion pattern shown on the feedback interface. Training with feedback off will occur as follows: The subject will walk on the treadmill and try to maintain the pattern without any form of visual or verbal feedback.
Kessler Foundation
West Orange, New Jersey, United States
RECRUITINGRoot mean square error of the knee flexion angle
The root-mean-square error of the knee flexion angle (RMSE\_KF) will be calculated between the measured and target knee flexion angles in the last ten strides of the last trial with feedback off in each training session.
Time frame: immediate after the first training session
Root mean square error of the knee flexion angle
The root-mean-square error of the knee flexion angle (RMSE\_KF) will be calculated between the measured and target knee flexion angles in the last ten strides of the last trial with feedback off in each training session.
Time frame: immediate after the second training session
Peak knee flexion angle
The Peak knee flexion angle (PKF) is the mean maximum knee flexion angles in the last ten strides of the last trial with feedback off.
Time frame: immediate after the first training session
Peak knee flexion angle
The Peak knee flexion angle (PKF) is the mean maximum knee flexion angles in the last ten strides of the last trial with feedback off.
Time frame: immediate after the second training session
Peak hip flexion angle
The Peak hip flexion angle (PHF) is the mean maximum knee flexion angles in the last ten strides of the last trial with feedback off.
Time frame: immediate after the first training session
Peak hip flexion angle
The Peak hip flexion angle (PHF) is the mean maximum knee flexion angles in the last ten strides of the last trial with feedback off.
Time frame: immediate after the second training session
Minimum relative phase angle between hip and knee
Minimum relative phase angle between hip and knee is the minimum difference in phase angle between hip and knee. Phase angle is computed as the inverse tangent of angular velocity divided by angular displacement.
Time frame: immediate after the first training session
Minimum relative phase angle between hip and knee
Minimum relative phase angle between hip and knee is the minimum difference in phase angle between hip and knee. Phase angle is computed as the inverse tangent of angular velocity divided by angular displacement.
Time frame: immediate after the second training session
Symmetry ratio of the stance phase
The symmetry ratio is calculated by dividing the smaller value by the larger value (trained vs. untrained lower limbs) of the stance phase time (% gait cycle). This results in a value between 0.0 and 1.0, with values closer to 1.0 indicating greater symmetry.
Time frame: immediate after the first training session
Symmetry ratio of the stance phase
The symmetry ratio is calculated by dividing the smaller value by the larger value (trained vs. untrained lower limbs) of the stance phase time (% gait cycle). This results in a value between 0.0 and 1.0, with values closer to 1.0 indicating greater symmetry.
Time frame: immediate after the second training session
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.