Toward flexible assistance for locomotor training: Design and clinical testing of a cable-driven robot for stroke, spinal cord injury, and cerebral palsy

Abstract

A cable-driven locomotor training system (3DCaLT) has been developed to improve the locomotor function in adults following hemispheric stroke or spinal cord injury (SCI) and children with cerebral palsy (CP). A key component of this new system is that it is highly backdrivable and allows for variation in the trajectory of the gait pattern. In addition, this new robotic system can provide controlled forces in both the sagittal and frontal planes at targeted phases of gait. The new robotic trainer uses a lightweight cable driven with controlled forces applied to the pelvis and leg (rather than a controlled trajectory). The 3DCaLT is compliant and gives patients the freedom to voluntarily move their pelvis and legs in a natural gait pattern while providing controlled assistance/resistance forces during body-weight-supported treadmill training (BWSTT). Thirty individuals post stroke, ten patients with SCI, and ten children with CP were recruited to participate in these pilot studies to test the feasibility of using the 3DCaLT for gait training. Results from these clinical studies indicate that locomotor gait training using the 3DCaLT resulted in a significant improvement of walking function in adults post stroke, with SCI, and children with CP. Thus, it seems feasible to use a flexible cabledriven robotic system, i.e., 3DCaLT, to improve the locomotor function in adults post stroke or with SCI, and children with CP. Further studies with a large sample size of subjects and a comparison of the current paradigm with conventional BWSTT are warranted.