Locomotor rehabilitation in a complex virtual environment.

Virtual reality (VR) technology offers a new and safe way to increase practice time and provide the varied environments and constraints needed to optimize locomotor training. Our specific objectives are (1) to create a virtual environment (VE) coupled with a self-paced treadmill for locomotor training; (2) to compare temporal and distance measurements of gait during treadmill walking while looking at different scenarios of VE; and (3) to develop a protocol optimized for the training of locomotor disorders after stroke. A motorized treadmill was mounted on a six-degree-of-freedom motion platform. VEs were created using commercial software (SoftImage) and projected on a large screen, while system control was administered through the CAREN software (Motek BV). The instantaneous treadmill speed and scene progression were servo-controlled. Preliminary results show that healthy subjects are able to have full control of their own walking speed both on the treadmill and within the virtual scene, while experiencing a strong sense of presence. A street crossing training protocol has been developed for locomotor training. It is expected that locomotor training with increasingly complex VEs will allow persons with stroke to increase progressively their locomotor capacity, as required and entrained by the VE.