Arm stiffness during assisted movement after stroke: the influence of visual feedback and training

Why are you even mentioning Bobath?

Bobath should have been shitcanned since 2003.

My best therapist supposedly used it but I really think her competence came from her knowledge of anatomy.

Physiotherapy Based on the Bobath Concept for Adults with Post-Stroke Hemiplegia: A Review of Effectiveness Studies 2003 

While there are wonderful mathematical calculations in here I see nothing that is going to help survivors recover. NO PROTOCOLS, nothing about recovery

The latest here:

Arm stiffness during assisted movement after stroke: the influence of visual feedback and training

 
 
TNSRE-2012-00064 1
 
 Abstract
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Spasticity and muscular hypertonus are frequently found in stroke survivors and may have a significant effect on functional impairment. These abnormal neuro-muscular properties, which are quantifiable by the net impedance of the hand, have a direct consequence on arm mechanics and are likely to produce anomalous motor paths. Literature studies quantifying limb impedance in stroke survivors have focused on multijoint static tasks and single joint movements. Despite this research, little is known about the role of sensory motor integration in post-stroke impedance modulation. The present study elucidates this role by integrating an evaluation of arm impedance into a robotically mediated therapy protocol. Our analysis had three specific objectives: 1) obtaining a reliable measure for the mechanical proprieties of the upper limb during robotic therapy; 2) investigating the effects of robot assisted training and visual feedback on arm stiffness and viscosity; 3) determining if the stiffness measure and its relationship with either training or visual feedback depend on arm position, speed, and level of assistance. This work demonstrates that the performance improvements produced by minimally assistive robot training are associated with decreased viscosity and stiffness in stroke survivors’ paretic arm and that these mechanical impedance components are partially modulated by visual feedback.
 Index Terms
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stiffness, arm impedance, stroke, robot therapy
I.
 
I
NTRODUCTION
STROKE is one of the most common diseases in the developed world and its incidence continues to rise [1]. Nearly 67% of all stroke survivors are left with physical disability [2] and approximately 25% lose their independence [1, 3]. Spasticity and muscular hyper-tonus are likely to limit the functional use of the paretic limb [4], thus impairing daily living activities. Moreover, reflex hyper-excitability of
muscles may lead to secondary complications such as pain, contracture, and reduction of range of motion. From a long term perspective, these complications may also result in structural changes in both connective tissue and muscle fibers [5, 6], although the contribution of these changes to functional deficits is controversial [7, 8]. Spasticity is a complex phenomenon defined as an exaggerated, velocity-dependent resistance to stretch; hyper-tonus, on the other hand, implies an overly increased resistance to the amount of stretch. Although both phenomena are difficult to describe with a simple model, it is generally accepted that a quantitative measurement of the mechanical impedance is at least a first order approximation for evaluating the combined effect of spasticity and hyper-tonus [9, 10]. The efficacy of several rehabilitation methods that specifically aim to reduce spasticity, such as the Bobath approach [11-14], is still controversial [15-18], as controversial is the interaction between assistive forces and spasticity during sessions of robotic therapy. The mechanical impedance of a limb depends on the mechanical properties of muscles and on neuromuscular activation patterns. Impedance is influenced by a number of factors, such as task, loading conditions, sensory feedback, adaptation and learning. In stroke survivors, damaged sensorimotor integration is an additional contributor to motor impairment and may influence arm stiffness modulation, as suggested by a recent work [19] in which subjects with high Modified Ashworth Score (MAS) found it easier to control the arm without visual feedback (VF). The clinical scales used to assess the degree of spasticity following stroke, including the most popular, the MAS [20], require a certain degree of subjective judgment. Their limited resolution is sufficient to categorize the gross impairment level of a subject, but insufficient to track finer modifications induced by treatments. In this framework, a reliable measure of the limb mechanical proprieties would be desirable to plan and understand the effect of rehabilitative (e.g. [11, 21]) and pharmacological (e.g. [22]) interventions aiming to reduce spasticity. Such quantitative measure will also allow the identification of differences in limb mechanics between individuals with similar impairments and the determination of the effects of different exercise conditions, such as visual or haptic feedback, via assistive forces. Limb impedance seems an appropriate quantitative descriptor: it has been used to quantify the relationship between limb mechanics and neural control during postural and movement tasks [23-32] and it seems a natural way to assess the control strategies compromised by stroke [33-36]. 

More at link.