Feasibility of a real-time pattern-based kinematic feedback system for gait retraining in pediatric cerebral palsy

Abstract

Introduction Visual biofeedback of lower extremity kinematics has the potential to enhance retraining of pathological gait patterns. We describe a system that uses wearable inertial measurement units to provide kinematic feedback on error measures generated during periods of gait in which the knee is predominantly extended (‘extension period’) and flexed (‘flexion period’). Methods We describe the principles of operation of the system, a validation study on the inertial measurement unit derived knee flexion angle on which the system is based, and a feasibility study to assess the ability of a child with cerebral palsy to modify a gait deviation (decreased swing phase knee flexion) in response to the feedback. Results The validation study demonstrated strong convergent validity with an independent measurement of knee flexion angle. The gait pattern observed during training with the system exhibited increased flexion in the flexion period with maintenance of appropriate extension in the extension period. Conclusions Inertial measurement units can provide robust feedback during gait training. A child with cerebral palsy was able to interpret the novel two phase visual feedback and respond with rapid gait adaptation in a single training session. With further development, the system has the potential to support clinical retraining of deviated gait patterns.

Reducing Slip Risk: A Feasibility Study of Gait Training with Semi-Real-Time Feedback of Foot–Floor Contact Angle

“…Multiple previous studies have investigated the utility of IMUs coupled with feedback systems for training gait kinematics in various populations [ 27 , 28 , 29 , 30 , 31 , 33 , 34 ]. Additionally, several studies have investigated the ability of such systems to support retained training effects [ 33 , 34 ].…”

“…Multiple previous studies have investigated the utility of IMUs coupled with feedback systems for training gait kinematics in various populations [ 27 , 28 , 29 , 30 , 31 , 33 , 34 ]. Additionally, several studies have investigated the ability of such systems to support retained training effects [ 33 , 34 ]. With respect to the immediate/real-time effects observed in this study, our findings are consistent with the findings of previously described feedback systems that have involved the use of IMUs placed on lower limbs coupled with feedback to provide cues regarding lower-extremity joint/segmental angles [ 27 , 28 , 29 , 30 , 31 , 33 , 34 ].…”

“…Additionally, several studies have investigated the ability of such systems to support retained training effects [ 33 , 34 ]. With respect to the immediate/real-time effects observed in this study, our findings are consistent with the findings of previously described feedback systems that have involved the use of IMUs placed on lower limbs coupled with feedback to provide cues regarding lower-extremity joint/segmental angles [ 27 , 28 , 29 , 30 , 31 , 33 , 34 ]. For example, Schließmann et al performed a proof-of-concept study involving IMUs placed on the feet to train the foot–ground angle at heel strike in older adults, participants with stroke, and participants with spinal cord injury [ 34 ].…”

“…Because kinematic data were not collected during this study, the strategies used by participants for whom changes were observed during the training portion of the session were unknown [ 34 ]. Other previous studies have reported a positive reduction in internal and external foot rotation during walking (foot progression angle) in healthy older adults [ 45 ] and young adults [ 46 ], and an increase in knee-flexion angle during the swing phase of gait for a participant with cerebral palsy [ 33 ] in response to real-time feedback.…”

“…For example, a feedback system with an IMU at the trunk has been demonstrated to reduce trunk tilt during walking [ 27 ]. Previous studies have also reported that IMUs measuring lower-limb kinematics paired with corresponding haptic or visual cues can correct excessive internal and external foot rotation during walking (i.e., foot progression angle) in healthy older adults [ 32 ] and increase insufficient knee-flexion angle during the swing phase of gait in a participant with cerebral palsy [ 33 ]. A proof-of-concept study supported the feasibility of foot-mounted IMUs to improve certain gait parameters including stance/swing time, stride length, and FFCA [ 34 ]; significant changes were observed for participants with spinal cord injury and older adults, but not for participants with stroke, when participants were provided with verbal feedback of foot angles [ 34 ].…”