The Role of Haptics in Physical Rehabilitation

Abstract

While the majority of today’s haptic interfaces and applications are targeted at the able-bodied user, a rapidly growing field of science studies the use of this technology in physical rehabilitation. There are many reasons the reader may wish to take a closer look at this application domain. One reason concerns societal impact, as there are about 70 million people with disabilities in the European Union [Buhler 97]. Such therapy is needed by various patient populations ranging from post-stroke survivors, to those with traumatic brain injury, cerebral palsy, spinal cord injuries, musculo-skeletal deficits, and others. The United States alone spends about $30 billion every year on physical rehabilitation [Patton et al. 06]. Of the above-mentioned costs, the majority represent labor costs (therapist time), and economic pressures tend to make rehabilitation interventions shorter than in prior years. Rehabilitation science, in contrast to current rehabilitation practice, has recently shown that intense and longer physical therapy will benefit even chronic patients through the phenomenon of “brain plasticity.” By repeating meaningful limb movements, similar to those done in activities of daily living (ADL), dormant neurons are recruited into new neural paths, and patients regain some of their lost function. Here robots are ideal, since they can train patients for the required long duration without tiring (unlike human therapists), and may eventually lead to a reduction in labor costs. Robotic systems coupled with virtual reality simulations bring additional improvements to today’s conventional physical therapy methods, since they introduce objective measures of performance. Data on total exercise time, speed and smoothness of movement, peak and average velocities, mechanical work, and endurance are among the variables that can be stored transparently and used to objectively gauge a patient’s progress. This is a clear departure from the subjective therapist’s evaluation of a patient, which is prevalent today.