An overview will be given to the workshop participants that demonstrates how early basic measurements of abnormal muscle synergies and associated abnormal torque coupling has led to scientific findings that explain impaired reaching abilities of the paretic arm of individuals with stroke. The subsequent development of a haptic robotic device, the ACT-3D, will be discussed highlighting the newfound capacity to quantify workspace of the paretic arm as a function of shoulder abduction load level that reflects the debilitating impact of abnormal muscle synergies on reaching function. It will be discussed how findings from this work provided the impetus for the development of a novel robotic training protocol that directly targets the impairment by providing progressive abduction loading during repetitive reaching toward targets throughout the workspace of the arm. Recent published results will be presented that show the ability to significantly increase the workspace of even the most severely impaired arms in individuals up to 29 years post-stroke.

The aim of this portion of the workshop will be to demonstrate how robotic devices can begin to elucidate the potential relationships between abnormal muscle synergies and hyperactive stretch reflexes in the paretic upper limb following chronic hemiparetic stroke. In particular, emphasis will be placed on the ability of the flexion synergy to flexibly modulate the classical stretch-induced short and long latency reflexes of the paretic elbow flexor muscles. Recent data collected using a novel robotic device, the ACT-4D, will be presented that highlights both the interplay between the flexion synergy and stretch reflexes as well as the utility of impairment-based robotic devices for the quantification of interrelated movement disorders. Additionally, this portion of the workshop aims to discuss potential future research directions that transition from perturbations applied during the maintenance of posture to implications for volitional movements. Specifically, the relationship between the expression of the flexion synergy, the manifestation of stretch reflexes, and volitional movement velocity will be explored.

Building upon the previous presentation, we will discuss the employment of the ACT-4D robot to quantify large range impedance about the elbow during various shoulder abduction loads. Specific attributes of the device that allow the separation of different sources of the impedance will be highlighted. We will discuss the potential effect of these on active range of motion, and recent results will be utilized to demonstrate how spasticity and synergies affect reaching function in individuals with chronic stroke. Finally, technical pitfalls common to robotic measurements of this type will be discussed including methods of prevention.

We will show results from a pilot study in our laboratory that evaluated the effect of a video game environment (air hockey) on reaching performance in individuals with stroke compared with traditional feedback of an avatar of the arm found in our previous intervention studies. Details of the gaming environment will be provided including the therapeutic rationale for various attributes of the game. Differences in achieved reaching performance will be discussed. We will present how the results from this study have steered some of our research efforts into the development of new robotic devices combined with custom made video games capable of targeting specific impairments and delivering the intervention protocol based on quantitative measurements of the progress made.
In conclusion, Robots can be very effectively used to measure motor impairments following brain injury. Furthermore, as underlying mechanisms become better understood due to the implementation of robotics, new robot mediated interventions can be developed and added to existing rehabilitation treatment repertoires. Finally, combining robot mediated haptic environments with gaming may generate novel and engaging neuro-rehabilitation environments that will increase acceptance of these new technologies by the therapists and patients as well as lead to greater adherence to exercise regimes.