Central nervous system (CNS) disorders distinctly impair locomotor pattern generation and balance, but technical limitations prevent independent assessment and rehabilitation of these subfunctions. Here we introduce a versatile robotic interface to evaluate, enable and train pattern generation and balance independently during natural walking behaviors in rats. In evaluation mode, the robotic interface affords detailed assessments of pattern generation and dynamic equilibrium after spinal cord injury (SCI) and stroke. In enabling mode, the robot acts as a propulsive or postural neuroprosthesis that instantly promotes unexpected locomotor capacities including overground walking after complete SCI, stair climbing following partial SCI and precise paw placement shortly after stroke. In training mode, robot-enabled rehabilitation, epidural electrical stimulation and monoamine agonists reestablish weight-supported locomotion, coordinated steering and balance in rats with a paralyzing SCI. This new robotic technology and associated concepts have broad implications for both assessing and restoring motor functions after CNS disorders, both in animals and in humans.
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We would like to acknowledge the excellent technical help provided by J. Heutschi, N. Wenger, M. Hürlimann, Q. Barraud and S. Duis for data collection and care of the rats, as well as A.S. Tafreshi for the design of the user interface to control the robotic system and A. Brunschweiler, A. Rotta and M. Fritschi for the realization of the suspension system. This work was supported by the National Centers of Competence in Research “Neural Plasticity and Repair” and “Robotics” of the Swiss National Science Foundation, the European Research Council (ERC 261247, “Walk Again”), European Community's Seventh Framework Programme (CP-IP 258654, NeuWALK), the Christopher and Dana Reeve Foundation and the Swiss National Science Foundation (subside 310030_130850).
The authors declare no competing financial interests.
Supplementary Figures 1–10 and Supplementary Table 1 (PDF 8470 kb)
Design and validation of the robotic interface (MOV 18902 kb)
Evaluation of optimal support conditions for motor pattern generation in spinal rats (MOV 19058 kb)
Evaluation of balance control capacities after a cortical stroke (MOV 7764 kb)
Propulsive neuroprosthetic interface (MOV 9793 kb)
Postural neuroprosthetic interface to enable precise paw placement after a cortical stroke (MOV 6650 kb)
Postural neuroprosthetic interface to enable coordinated locomotion in rats with a cervical hemisection (MOV 8024 kb)
Postural neuroprosthetic interface to enable coordinated locomotion in rats with paralyzing SCI (MOV 9977 kb)
Robot-enabled locomotor training restores equilibrated steering in rats with paralyzing SCI (MOV 24035 kb)
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Dominici, N., Keller, U., Vallery, H. et al. Versatile robotic interface to evaluate, enable and train locomotion and balance after neuromotor disorders. Nat Med 18, 1142–1147 (2012). https://doi.org/10.1038/nm.2845
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