Variable Stiffness Treadmill (VST)

Abstract: Gait requires kinematic and dynamic coordination of the limbs and muscles, multi-sensory fusion and robust control mechanisms. We are using a novel system, called the Variable Stiffness Treadmill (VST), in order to understand inter-leg coordination sensorimotor mechanisms, and utilize them for a new approach to rehabilitation of hemiparetic gait. The device is revolutionary since it allows for the real-time control of a split-belt treadmill stiffness. By controlling the stiffness of the treadmill we can precisely vary both force and kinematic feedback to the subject’s lower limb, and study the effects of these perturbations on the sensorimotor mechanisms for gait. The overarching goal of the project is to take advantage of those sensorimotor control principles and apply them to robotic-assisted model-based gait rehabilitation using the VST.

Results: Results so far show that unilateral treadmill stiffness disturbances evoke contralateral leg responses controlled by supraspinal pathways, while these responses are highly affected by the timing and parameters of the perturbations. Results with both healthy and hemiparetic subjects show that unilateral stiffness perturbations using the VST can evoke controllable and repeatable muscular activations on the contralateral-unperturbed leg. Brain recordings during those activations (via EEG) provide evidence that the involved mechanisms include supraspinal pathways.

Funding: This work is supported by the National Science Foundation (2017-2020, Award #2015786) and Piper Health Solutions Seed Grant (2013-2014).

Publications: (see Publications page for a more recent list of papers)

Jeffrey Skidmore and Panagiotis Artemiadis. “A Comprehensive Analysis of Sensorimotor Mechanisms of Inter-Leg Coordination in Gait Using the Variable Stiffness Treadmill: Physiological Insights for Improved Robot-Assisted Gait Therapy.” In 2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR), pp. 28-33. IEEE, 2019. [pdf]

Jeffrey Skidmore and Panagiotis Artemiadis, “Unilateral Changes in Walking Surface Compliance Evoke Dorsiflexion in Paretic Leg of Impaired Walkers,” Journal of Rehabilitation and Assistive Technologies Engineering, 4: 2055668317738469, 2017 [link to pdf]

Linda Fou, Jeffrey Skidmore and Panagiotis Artemiadis, “The Variable Impedance Treadmill (VIT) for Robot-assisted Rehabilitation,” Biomedical Engineering Society (BMES) 2017.

Jeffrey Skidmore and Panagiotis Artemiadis, “Sudden changes in walking surface compliance evoke contralateral EMG in a hemiparetic walker: a case study of inter-leg coordination after neurological injury,’’ 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC’16), pp. 4682-4685, 2016. [pdf]

Jeffrey Skidmore and Panagiotis Artemiadis, “Unilateral Floor Stiffness Perturbations Systematically Evoke Contralateral Leg Muscle Responses: a New Approach to Robot-assisted Gait Therapy,” IEEE Transactions on Neural Systems and Rehabilitation Engineering, vol. 24(4), pp. 467-474, 2016. [pdf]

Jeffrey Skidmore and Panagiotis Artemiadis. “On the effect of walking surface stiffness on inter-limb coordination in human walking: toward bilaterally informed robotic gait rehabilitation.” Journal of NeuroEngineering and Rehabilitation, 13.23, pp 1-15, 2016. [link to pdf]

Jeffrey Skidmore and Panagiotis Artemiadis “Unilateral Walking Surface Stiffness Perturbations Evoke Brain Responses: Toward Bilaterally Informed Robot-assisted Gait Rehabilitation,” IEEE International Conference on Robotics and Automation (ICRA), pp. 3698-3703, 2016. [pdf]

Jeffrey Skidmore and Panagiotis Artemiadis “Leg Muscle Activation Evoked by Floor Stiffness Perturbations: A Novel Approach to Robot-assisted Gait Rehabilitation,” IEEE International Conference on Robotics and Automation (ICRA), pp. 6463-6468, 2015. [pdf]

Ryan Frost, Jeffrey Skidmore, Marco Santello and Panagiotis Artemiadis, “Sensorimotor control of gait: A novel approach for the study of the interplay of visual and proprioceptive feedback,” Frontiers in Human Neuroscience 9:14, 2015. [link to pdf]

Jeffrey Skidmore, Andrew Barkan and Panagiotis Artemiadis, “Variable Stiffness Treadmill (VST): System Development, Characterization and Preliminary Experiments,” IEEE/ASME Transactions on Mechatronics, vol. 20, issue 4, pp. 1717-1724, 2015. [pdf]

Jeffrey Skidmore, Andrew Barkan and Panagiotis Artemiadis, “Investigation of Contralateral Leg Response to Unilateral Stiffness Perturbations using a Novel Device,” IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 2081-2086, 2014. [pdf]

Andrew Barkan, Jeffrey Skidmore, Panagiotis Artemiadis, “Variable Stiffness Treadmill (VST): a Novel Tool for the Investigation of Gait,” IEEE International Conference on Robotics and Automation (ICRA), pp. 2838-2843, 2014. [pdf]

Patents

Panagiotis Artemiadis and Jeffrey Skidmore. “Systems and methods for gait rehabilitation using mechanical perturbations.” U.S. Patent No. 9,707,442. 18 Jul. 2017.

Panagiotis Artemiadis and Andrew Barkan, “Variable Stiffness Treadmill System”, U.S. Patent No. 9,757,610. 12 Sep. 2017.