Asymmetric Dual Arm Approach For Post Stroke Recovery Of Motor Functions Utilizing The EXO-UL8 Exoskeleton System: A Pilot Study

Abstract

In a dual arm therapeutic regime aiming to rehabilitate motor functions post stroke, both the affected arm (paretic) and the unaffected (non-paretic) arm are involved. In this context, the leading idea is that motor functions of the affected arm during a reaching task may be improved if the unaffected arm has already reached the target. As part of this pilot study, one chronic post-stroke patient with weakness and spasticity on his right arm conducted reaching tasks to virtual targets arranged in a $5\times 3$ matrix located parallel to his frontal plane, in two different configurations: (1) affected arm only (without assistance from the exoskeleton); (2) unaffected arm first followed by the affected arm (2a) without, and (2b) with assistance. A force field attracting the wrist of the affected arm to the target was used in the assistive mode. The data post-processing and analysis included task completion time, reachable task space, joint range of motion, human-robot interaction force/torque and power exchange at multiple sensors along the arm - visualized in a series of interaction maps. The data validated the robotic system's basic functionality in facilitating post-stroke unilateral and asymmetric bilateral training. Future work would be expanded to clinical trials with more subjects to be recruited and additional features to be implemented.