From theoretical analysis to clinical assessment and intervention: Three interactive motor skills in a virtual environment

Rehabilitation of upper extremity has successfully focused on simple reaching movements using assistive robotic devices in concert with virtual interactive displays. When commercial gaming technology is adapted to clinical use, the movements often are more complex but also less controlled. While motivating games engage the patients, the more controlled robot-assisted paradigms afford more focused quantitative assessment and intervention. Our lab has developed three experimental tasks, implemented in virtual reality environments, that combine physically controlled movements with gaming aspects: Throwing a ball, carrying a cup of coffee, and rhythmically bouncing a ball. All three paradigms are grounded in theoretical analysis of the physics of the task before their virtual implementation. On the basis of the mathematical model of the abstracted physics, novel analyses of human performance were developed that go beyond simple outcome measures and quantify essential aspects movement control: timing, variability, safety margins. Basic research on healthy subjects laid the groundwork for using these experimental platforms for (pre)-clinical assessment and intervention in patients with neurological disorders. We present three studies on Parkinson patients, children with dystonia, and older adults to exemplify the potential of these experimental tasks for assessment and targeted intervention.