Design and validation of an upper extremity kinematic model for application in stroke rehabilitation

Design and validation of a new upper extremity (UE) motion assessment system was completed to evaluate recovery progress during stroke rehabilitation. This UE model was constructed to accurately track the three-dimensional (3-D) orientation of the trunk, shoulder, elbow, and wrist during task performance. Linear static, linear dynamic and angular dynamic validation was completed to determine the resolution and accuracy of the system. Marker spacing was evaluated for both resolution and accuracy for 50, 150, and 300 mm. The system was then applied to a pilot study with stroke subjects. Linear static resolution was greatest along the y-axis (0.17±0.26 mm) and poorest along the z-axis (0.90±0.86 mm) at the 0.05 level of significance. The overall linear static accuracy of the system was in excess of 99%. Mean linear dynamic resolution and accuracy are 0.98± 0.30 mm and 99.9%, respectively. Angular dynamic validation demonstrated a mean resolution of 0.84±0.80 degrees and mean accuracy of 99.6% in the three clinical planes. The quantitative validation results as well as pilot subject tests indicate the system is suitable for further clinical assessment.