MECHANICALLY INDUCED STOCHASTIC RESONANCE TO IMPROVE AMPUTEE GAIT AND BALANCE

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. OBJECTIVE: One of the many complications of diabetes is the loss of sensation in the feet. This sensory deficit can negatively impact the postural stability and mobility of non-amputees, since without feedback, it is simply more difficult to stand and walk. For lower limb amputees, the problem is compounded. These patients often have difficulty with prosthetic limb placement during maneuvering tasks, exhibit dramatic increases in the movement of their center of pressure during quiet standing, and both clinical and observational gait analysis reveal significant changes in their gait pattern relative to non-amputees. Our work proposes to explore the use of a novel prosthetic intervention for diabetic lower limb amputees. We hypothesize that our intervention will sufficiently enhance proprioception to result in measurably improved postural stability and locomotor function for these patients. The intervention is based on a phenomenon known as stochastic resonance, whereby the application of sub-threshold vibration enables mechano-receptors previously unable to respond to stimuli to become more susceptible to depolarization. For persons with neuropathic proprioceptive losses, stochastic resonance may facilitate a functional response from subtle stimuli where gross inputs were formerly required. The objective of the proposed research is to discover if machanical stochastic resonance of the surface of the residual limb will improve the postural stability and mobility of diabetic transtibial amputees. RESEARCH PLAN: We propose to recruit diabetic transtibial amputees to wear a study prosthetic socket which has been specially built to produce stochastic resonance using miniature vibratory motors. To measure the intervention effect on postural stability, we will conduct a quantitative computerized sway experiment and employ an additional test that measures balance during representative daily activities (Berg Balance Scale). To measure the effect on locomotor function, we will conduct a clinical instrumented gait analysis and a test that measures dynamic balance and function (Expanded Timed Get-up and Go). METHODS: The proposed study is a within-subject design where we will compare measures of balance and gait with and without the application of stochastic resonance through a study prosthetic socket worn by the below-knee amputee. A group of normal subjects will be enrolled as well to aid in protocol development. CLINICAL RELEVANCE: For lower limb amputees with neuropathic complications from diabetes, the proposed research is the first step toward developing a new and clinically feasible approach to improving their mobility and reduding their risk of fall-related injuries.