Principal Investigator: Felix E. Zajac PhD Project Staff: George Chen MS; Carolynn Patten PhD, PT; Charges G. Burgar, MD; and Steven A. Kautz PhD Project Category: Stroke Objective: The overall objective is to develop gait training approaches using harness-supported treadmill training for persons with post-stroke hemiparesis. Central to this objective is the understanding of the biomechanics of harness-supported treadmill walking since it dictates, in a large way, the sensory inputs associated with the task and the motor coordination reinforced. Research Plan: We have developed a harness support that permits the incremental adjustment of body weight support and harness-support compliance and the measurement of harness forces applied to the subject in the vertical, anterior-posterior, and lateral directions. In this pilot study, kinematic, insole pressure, and harness force data will be collected as subjects walk overground and on a treadmill at different settings of body weight support, treadmill speed, and harness-support compliance. Kinematics (trunk position and joint angles at the hip, knee, and ankle during the gait cycle) will be measured using five digital video cameras positioned to capture 3-D marker locations. Harness forces (vertical, anterior-posterior, and lateral) applied to the subject will be quantified using our custom-made harness support frame instrumented with a 6-axis force/torque sensor. Vertical ground reaction forces produced by each leg will be measured using insole pressure sensors. Data collected at each training parameter setting (setting of body weight support, treadmill speed, and harness-support compliance) will be compared to examine how different settings of training parameters affect gait symmetry in a selected group of hemiparetic subjects (n=6) and age- and speed-matched controls during treadmill walking. Work Accomplished: We have collected kinematics, harness forces, and insole pressure data from six neurologically healthy subjects and six persons with post-stroke hemiparesis who walked on the treadmill at different speeds in the harness configured for different amounts of body support, harness compliance, and with or without hand-hold. Preliminarily, we have found that neurologically healthy and hemiparetic subjects interact differently mechanically with the harness. For example, in neurologically healthy subjects, harness-support compliance affected fluctuation in vertical harness support, which altered vertical ground reaction force profiles. In the hemiparetic subjects, harness-support compliance affected vertical harness support on the paretic limb and anterior-posterior harness force fluctuation magnitude. Therefore, differences in gait mechanics due to harness-support compliance could influence afferent information important to treadmill training. 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 |
