| Home | Publications | Proceedings |
Introduction: Many different forms of gait training with body weight support (canes, therapeutic pools, and overhead harness systems) have been used to restore ambulation in different patient populations. A novel system has been designed to provide supported walking using air pressure. The system consists of a treadmill enclosed in a flexible bag. A subject is positioned on the treadmill and the bag is sealed at waist level, enclosing the lower body in an airtight chamber. Air pressure in the chamber is increased below the waist relative to above the waist. The differential pressure creates a buoyant force.
Objective: The overall objective is to determine the physiological effects of walking in the system and to characterize the relationship between intra-chamber pressure, body size and reduction of ground reaction forces.
Clinical Relevance: Aging veterans and the rest of the aging population are at an increased risk for mobility impairments. Developing more effective rehabilitation techniques for treating gait dysfunction may reduce hospitalization and improve functional outcomes. Currently, subjects with hemiplegia are being studied to determine the potential to improve functional walking ability and gait mechanics using this system.
Methods: Ten subjects with stable cardiac, vascular and/or respiratory disorders were tested to examine the physiological response to walking with differential pressure compared to walking without differential pressure. An additional ten subjects reflecting a wide spectrum of body weight, height and waist girth were tested to determine the relationship between system pressure, anthropometric characteristics and ground reaction force reduction.
Results: All subjects were able to complete the entire testing session without adverse effects. When comparing time and subject matched vital signs while walking with no air pressure to walking with maximal air pressure support, no significant differences were seen in heart rate, mean arterial pressure, respiratory rate, oxygen saturation or limb circumference. All subjects comfortably tolerated the intra- chamber pressures needed to support up to 75% of body weight (0.68 - 1.07 psi). Height was shown to be the most significant predictor of the pressure needed to determine body weight support. Ground reaction forces decreased with increasing intra-chamber pressure.
Conclusions: Walking with air pressure support was subjectively comfortable and appears to be safe for subjects tested with medically stable cardiac, vascular and respiratory disorders. Intra-chamber pressures of less than 1.1 psi provided up to 75% body weight support with concomitant reduction in ground reaction force.
Acknowledgments: VA Merit Review (A2070-RA)