Robotics and Virtual Reality Applications in Mobility Rehabilitation

Gait training is a method to reduce mobility dysfunction. Diverse patient populations exhibit mobility impairments that can be ameliorated with gait training. Two such populations are people post-stroke and post-spinal cord injury. The ability to walk is one of several functions affected by stroke. Immediately after the stroke only 37% of the survivors are able to walk (Jorgensen et al., 1995). Of the patients with initial paralysis only 21% regain walking function (Wandel et al., 2000). Another patient population that can benefit from gait training (Dietz et al., 1998; Nicol et al., 1995) is the spinal cord injury victims. According to the Travis Roy Foundation there are currently between 250,000 and 400,000 Americans living with spinal cord injury. Gait training or locomotion therapy uses several devices to assist the patient move and maintain balance. Canes, crutches, walkers, and platforms are simple ambulatory assistive devices that modify a patient’s independence and functional mobility. Treadmills often equipped with un-weighing devices are used for training walking at various speeds on a straight flat surface or small incline. These features, along with treadmills’ simple design and affordable costs are sufficient reasons for their popularity. Treadmills, however, cannot render more complex walking surfaces which patients encounter daily, such as: stairs, curves, uneven surfaces (e.g. cobblestone paths), or surfaces with various stiffness or friction coefficients. Training patients to negotiate complex walking surfaces can be done either through in-vivo training assisted by a physical therapist, or through using devices able to simulate such surfaces. The former approach often takes the patient out of the controlled clinic environment, which is not always feasible and may raise safety concerns. The latter approach may offer an alternative to real environment training. It would allow patients to exercise in controlled and safe conditions in the clinic, which could potentially be more time and personnel efficient than real environment training, In this context, numerous research projects have approached gait simulators trying to create robotic devices that could render complex walking surfaces. The integration of such robotic systems with virtual environments may, in theory, expand the range of applications to entertainment and real-life task training of patients with walking dysfunction. The appealing reasons for using such systems are the flexibility and