Principal Investigator: Felix E. Zajac, PhD Project Staff: George Chen, PhD; Carolynn Patten, PhD, PT; Charles G. Burgar, MD; and Steven A. Kautz, PhD Project Category: Stroke - 2003 Treadmill training with harness support is a promising, task-oriented approach to restoring locomotor function in individuals with post-stroke hemiparesis. We assessed the potential of body weight support, treadmill speed, support stiffness, and handrail hold (i.e., training parameters) to improve significant gait deviations associated with post-stroke hemiparesis during treadmill walking. Research Plan: A harness support that permits the incremental adjustment of body weight support and support stiffness and measurement of 3-D harness forces was built. A camera setup to capture bilateral kinematic data during treadmill walking was configured. Data was collected from six hemiparetic subjects and six non-disabled, healthy controls as they walked at matched treadmill speeds with different selections of training parameters. Non-speed-related gait deviations associated with post-stroke hemiparesis were identified by comparing the gait of hemiparetic and non-disabled subjects during treadmill walking without harness support and handrail hold. Improvement in the identified gait deviations with the adjustment of the training parameters were assessed in the hemiparetic subjects. Work Accomplished: Many gait deviations in the hemiparetic group were consistent with impaired swing initiation and single limb support in the paretic limb and related compensatory strategies. Leg kinetic energy at toe-off in the paretic limb was reduced, resulting in increased percentage swing time and reduced peak knee flexion during swing, consistent with inadequate swing initiation by the plantarflexors. Energy cost associated with raising the trunk during pre-swing and swing of the paretic limb was exaggerated, consistent with compensatory pelvic hiking for toe clearance. Leg kinetic energy at toe-off in the non-paretic limb was increased, resulting in reduced swing time, consistent with weakness or poor balance during paretic limb support. The adjustment of each training parameter improved a specific set of the identified gait deviations. With increased body weight support or the addition of handrail hold, the increased leg kinetic energy at toe-off of the non-paretic limb was reduced and its short swing time lengthened, resulting in improved temporal symmetry and increased single limb support time of the paretic limb. With increased treadmill speed, leg kinetic energy at toe-off in the paretic limb was increased. With increased support stiffness, the exaggerated energy cost associated with raising the trunk was reduced. Deviations in swing phase kinematics in the paretic limb were not improved with the adjustment of training parameters and probably need to be addressed using manual assistance. Expected Outcome: Understanding how abnormal gait mechanics and harness forces interact will lead to improved training parameters for rehabilitation of persons with neurological impairments. Funding Source: VA RR&D Merit Review Funding Status: Funded |
