Quantitative evaluations of ankle spasticity and stiffness in neurological disorders using manual spasticity evaluator

Rehabilitation Institute of Chicago, Chicago, IL 60611, USA.
The Journal of Rehabilitation Research and Development (Impact Factor: 1.43). 01/2011; 48(4):473-81. DOI: 10.1682/JRRD.2010.04.0053
Source: PubMed


Spasticity and contracture are major sources of disability in people with neurological impairments that have been evaluated using various instruments: the Modified Ashworth Scale, tendon reflex scale, pendulum test, mechanical perturbations, and passive joint range of motion (ROM). These measures generally are either convenient to use in clinics but not quantitative or they are quantitative but difficult to use conveniently in clinics. We have developed a manual spasticity evaluator (MSE) to evaluate spasticity/contracture quantitatively and conveniently, with ankle ROM and stiffness measured at a controlled low velocity and joint resistance and Tardieu catch angle measured at several higher velocities. We found that the Tardieu catch angle was linearly related to the velocity, indicating that increased resistance at higher velocities was felt at further stiffer positions and, thus, that the velocity dependence of spasticity may also be position-dependent. This finding indicates the need to control velocity in spasticity evaluation, which is achieved with the MSE. Quantitative measurements of spasticity, stiffness, and ROM can lead to more accurate characterizations of pathological conditions and outcome evaluations of interventions, potentially contributing to better healthcare services for patients with neurological disorders such as cerebral palsy, spinal cord injury, traumatic brain injury, and stroke.

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Available from: Nicole A Wilson, Sep 10, 2014
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    • "The robot allows 25 o of dorsi-flexion, 45 o of plantar-flexion, 25 o of inversion, 15 o of eversion, and 15 o of internal or external rotation. These numbers are near the ROM for normal children, which is markedly larger than that of children with CP [31] and beyond what is required for typical gait. The robot can be used both in a sitting position and during walking and gives independent, active assistance in 2 of the 3 DOF, namely DP flexion and IE, and a passive DOF for internalexternal rotation following our approach to minimize the need for proper robot alignment [32]. "
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    ABSTRACT: This paper presents the pediAnklebot, an impedance-controlled low-friction, backdriveable robotic device developed at the Massachusetts Institute of Technology that trains the ankle of neurologically impaired children of ages 6-10 years old. The design attempts to overcome the known limitations of the lower extremity robotics and the unknown difficulties of what constitutes an appropriate therapeutic interaction with children. The robot’s pilot clinical evaluation is on-going and it incorporates our recent findings on the ankle sensorimotor control in neurologically intact subjects, namely the speed-accuracy tradeoff, the deviation from an ideally smooth ankle trajectory, and the reaction time. We used these concepts to develop the kinematic and kinetic performance metrics that guided the ankle therapy in a similar fashion that we have done for our upper extremity devices. Here we report on the use of the device in at least 9 training sessions for 3 neurologically impaired children. Results demonstrated a statistically significant improvement in the performance metrics assessing explicit and implicit motor learning. Based on these initial results, we are confident that the device will become an effective tool that harnesses plasticity to guide habilitation during childhood.
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    The Journal of Rehabilitation Research and Development 01/2011; 48(4):vii-x. DOI:10.1682/JRRD.2011.02.0014 · 1.43 Impact Factor
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