Mobility Research

Disturbance Response in Amputee Gait

Errors in foot placement while avoiding obstacles and maneuvering in the household and community environments may lead to falls and injuries. This research aims to develop an ankle that can invert and evert and thereby control the center of pressure under the prosthetic foot; enhancing balance and stability of lower limb amputees.

Foot-Ankle Stiffness

Many ambulatory lower limb amputees exhibit fatigue, asymmetrical gait, and the inability to walk at varying speeds. We are using a rapid prototyping approach to fabricate feet of varying stiffness for exploring the effects of foot stiffness on amputee gait.

Turning Gait

Turning corners and maneuvering around obstacles are essential abilities for successful community and household ambulation. The aim of this research is to test the efficacy of a compliant torque adapter in the pylons of transtibial amputees.

Energy Storage & Release

Many ambulatory lower limb amputees exhibit fatigue, asymmetrical gait, and the inability to walk at varying speeds. We are developing and testing several approaches aimed at providing the propulsive forces necessary to alleviate these problems.

Stochastic Resonance

Stochastic resonance (sub-threshold vibration) may enhance peripheral sensation sufficiently to result in improved postural stability and locomotor function. This research explores application of this phenomenon to the residual limb and intact plantar surface of diabetic lower limb amputees.

Injury Prevention Research

Vacuum Suspension Systems

Many amputees live with an ill-fitting socket and can experience limb pistoning within the socket, which in turn may result in skin irritation, tissue breakdown, discomfort, and a reduction in activity. The aims of this research are to characterize the response of the lower residual limb to a vacuum suspension system and to measure changes in limb volume with a structured light scanning system.

Socket Systems & Tissue O₂

Limb health and wound healing capacity is closely related to the amount of oxygen present in limb tissues. Using our fiber-optic video-oximetry imaging system, we aim to discover if prosthetic prescription can influence residual limb tissue oxygenation during both rest and gait.

Distributed Sensing

The goal of the proposed project is to develop enabling sensing technology based on a flexible array and to build a prototype of a prosthetic liner with distributed, unimodal field sensing capability. The specific aims include: (1) the design of the flexible sensing array for measurement of moisture, temperature, pressure, and shear stress; (2) integration of this array into a prosthetic liner/socket; and (3) testing of device performance.

Torsional Prosthesis

This research seeks to develop a prosthetic limb whose torsional characteristics can adapted depending activity. Our goal is to reduce torsional stresses and the incidence of residual limb injuries.

Patient Comfort Research

Thermal Comfort

Lower limb amputations often experience discomfort related in part to higher skin temperatures within their prosthetic socket. Our research has found prosthetic liners and sockets are excellent insulators that can retain heat. Activity can cause a dramatic increase in skin temperature within the prosthesis requiring substantially long periods of inactivity to restore resting state temperatures. Our current work involves developing active cooling systems and embedded sensor networks to monitor skin temperature.

Evaporative Cooling and Perspiration Removal

Amputees often complain about uncomfortably warm residual limb skin temperatures and the accumulation of perspiration within their prosthesis. This research will discover if a novel evaporative cooling system can provide ameliorate these problems.

Research Areas & Future Directions

Current Project Summaries

• Development of Controlled Energy Storage and Release Prosthetic Foot
• Development of Inverting-Everting Prosthesis
• Development of Variable Stiffness Prosthetic Ankle
• Diabetic Thermoregulation and Perception of Comfort
• Distributed Sensors for Prosthetic Sockets
• Disturbance Response in Lower Limb Amputee Gait
• Field Measurements of Lower Limb Skin Temperatures During Snow Shoeing
• Mechanically-induced Stochastic Resonance
• Negative Gauge Pressure Moisture Management and Secure Adherence Device
• Prosthetic Knee-Ankle-Foot System
• Residual Limb Skin Temperatures and Prosthesis Effects on Heat Transfer
• Socket System Effect on Tissue Oxygenation
• Transverse Plane Pylon Stiffness Effect
• Turning Corners
• Vacuum Suspension

Correspondence

Glenn Klute, Ph.D. 206-277-6724 Seattle VA Medical Center, University of Washington gklute@u.washington.edu Program contact information: Wesley Edmundson 206-764-2991 Wesley.Edmundson@va.gov VA Puget Sound Health Care System, ms 151 1660 S. Columbian Way Seattle, WA 98108