The Lower Extremity Ambulation Feedback System for Analysis of Gait Asymmetries: Preliminary Design and Validation Results

Abstract

In Brief Asymmetric gait, commonly referred to as “limping,” is frequently seen in individuals with a variety of musculoskeletal and neurologic conditions. Asymmetric gait impacts the metabolic cost of ambulation and the development of osteoarthritis and also affects the cosmetic appearance of gait. This is especially true for individuals with lower limb amputations who ambulate with prosthetic limbs. The Lower Extremity Ambulation Feedback System (LEAFS) is a shoe-insert device that uses force sensors to evaluate asymmetries in gait and provide auditory feedback when an asymmetric gait threshold is reached. The aim of this study was to validate the ability of the LEAFS to accurately measure stance time and detect asymmetries in stance time. A prospective, consecutive case series study design was used. The study population consisted of individuals with lower limb amputations at the transtibial level. Data were collected simultaneously using both the LEAFS and a force plate and markers on the foot in a clinical motion analysis laboratory as subjects ambulated at their self-selected walking speed. The methods comparison approach of Bland and Altman was used to validate the measurement of stance time, and two-sample t-tests were used to validate the detection of asymmetry. The LEAFS determined the stance time with a bias error of −10.4 ± 37.2 ms, when compared with the clinical motion laboratory, and detected the same asymmetries in stance time for subjects with unilateral amputation (a shorter stance time on the limb with the prosthetic, when compared with the intact limb) as the clinical motion laboratory. Asymmetric gait impacts the metabolic cost of ambulation and the development of osteoarthritis and also affects the cosmetic appearance of gait. The Lower Extremity Ambulation Feedback System (LEAFS) is a shoe-insert device that uses force sensors to evaluate asymmetries in gait and provide auditory feedback when an asymmetric gait threshold is reached. The aim of this study was to validate the ability of the LEAFS to accurately measure stance time and detect asymmetries in stance time.