Multimodal Motion Capture Toolbox for Enhanced Analysis of Intersegmental Coordination in Children with Cerebral Palsy and Typically Developing.

Three-dimensional marker-based motion capture systems are the gold standard for evaluating kinematic patterns in human movement, offering precise quantification of segment and joint positions. However, traditional marker-based systems pose several challenges, particularly for children with neurological disabilities and sensory processing abnormalities, such as those observed with children with cerebral palsy. These challenges hinder the use of kinematic markers and limit detailed analyses of movement patterns. Recent advancements in markerless motion capture systems utilizing deep learning-based human pose estimation allowed us to explore cost-effective alternatives to traditional optical systems and the subsequent data processing approaches. An integrated toolbox was developed, combining multiple motion capture technologies: research-grade kinematic equipment, kinematic clusters, inertial measurement units, three-dimensional (3D) markerless systems, and two-dimensional (2D) markerless systems with commercially available cameras (via MediaPipe). For this current study, we present the outcomes of 3D marker-based versus 2D markerless motion capture, the major ongoing issue in human subjects' biomechanical studies, to describe coordinative patterns via hip-knee angle-angle plots. The cyclogram approach was selected because it offers a robust metric and readily interpretable framework for analyzing coordination via coupled motion between body segments. Two typically developing children and two children with cerebral palsy performed a functional movement pattern, the sit-to-stand task. The findings here demonstrated the feasibility of integrating multimodal systems for kinematic analyses, providing flexibility for research and clinical settings. Moreover, the novel open-source approach presented in this work addresses the challenges posed by many patient populations experiencing sensory processing issues, allowing for an advanced and individualized plan of care.