Compensating the Symptomatic Increase in Plantarflexion Torque and Mechanical Work for Dorsiflexion in Patients with Spastic Paresis Using the “Hermes” Ankle–Foot Orthosis
Prosthesis, vol. 7, pp. 12
Abstract
Background/Objectives: “Hermes” is an ankle–foot orthosis (AFO) with negative stiffness designed to mechanically compensate the symptomatic increase in plantarflexion (PF) torque (i.e., ankle joint torque resistance to dorsiflexion, DF) in patients with spastic paresis. Methods: The effectiveness of “Hermes” was evaluated in twelve patients with chronic unilateral spastic paresis after stroke. Using a robotic ankle manipulator, stiffness at the ankle joint was assessed across three conditions: ankle without Hermes (A), ankle with Hermes applying no torque compensation (A+H0%), and ankle with Hermes tuned to compensate 100% of the patients’ ankle joint stiffness (A+H100%). Results: A significant reduction in PF torque was found with Hermes applying compensation (A+H100%) compared to the conditions without Hermes (A) and with Hermes applying no compensation (A+H0%). Furthermore, a significant reduction in positive dorsiflexion work was found with Hermes applying compensation (A+H100%) compared to the condition with Hermes applying no compensation (A+H0%). Hermes did not significantly contribute to additional PF torque or positive work when applying no compensation (A+H0%). Conclusions: The reductions in PF torque achieved with Hermes are comparable to those seen with repeated ankle stretching programs and ankle robot training. Thus, Hermes is expected to assist voluntary dorsiflexion and improve walking in patients with spastic paresis.
Authors 9
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Karen E. Rodriguez Hernandez corresponding
Delft University of Technology
Affiliation as printed
Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, 2628 CD Delft, The Netherlands
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Leiden University · Leiden University Medical Center
Affiliation as printed
Department of Rehabilitation Medicine, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
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Leiden University · Leiden University Medical Center · Spaarne Ziekenhuis
Affiliation as printed
Department of Rehabilitation Medicine, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
Spaarne Gasthuis Hoofddorp, Spaarnepoort 1, 2134 TM Hoofddorp, The Netherlands
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Affiliation as printed
InteSpring BV, Patrijsweg 24, 2289 EX Rijswijk, The Netherlands
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Leiden University · Leiden University Medical Center
Affiliation as printed
Department of Rehabilitation Medicine, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
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Leiden University · Leiden University Medical Center · Spaarne Ziekenhuis
Affiliation as printed
Department of Rehabilitation Medicine, Leiden University Medical Centre, 2300 RC Leiden, The Netherlands
Spaarne Gasthuis Hoofddorp, Spaarnepoort 1, 2134 TM Hoofddorp, The Netherlands
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Delft University of Technology
Affiliation as printed
Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, 2628 CD Delft, The Netherlands
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University of Twente · Delft University of Technology
Affiliation as printed
Department of Biomechanical Engineering, Faculty of Engineering Technology, University of Twente, 7500 AE Enschede, The Netherlands
Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, 2628 CD Delft, The Netherlands
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Delft University of Technology
Affiliation as printed
Department of Biomechanical Engineering, Faculty of Mechanical Engineering, Delft University of Technology, 2628 CD Delft, The Netherlands
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