Validity and reliability of wearable inertial sensors in healthy adult walking: a systematic review and meta-analysis

Abstract

Background: Inertial measurement units (IMUs) offer the ability to measure walking gait through a variety of biomechanical outcomes (e.g., spatiotemporal, kinematics, other). Although many studies have assessed their validity and reliability, there remains no quantitive summary of this vast body of literature. Therefore, we aimed to conduct a systematic review and meta-analysis to determine the i) concurrent validity and ii) test-retest reliability of IMUs for measuring biomechanical gait outcomes during level walking in healthy adults. Methods: Five electronic databases were searched for journal articles assessing the validity or reliability of IMUs during healthy adult walking. Two reviewers screened titles, abstracts, and full texts for studies to be included, before two reviewers examined the methodological quality of all included studies. When sufficient data were present for a given biomechanical outcome, data were meta-analyzed on Pearson correlation coefficients (r) or intraclass correlation coefficients (ICC) for validity and reliability, respectively. Alternatively, qualitative summaries of outcomes were conducted on those that could not be meta-analyzed. Results: A total of 82 articles, assessing the validity or reliability of over 100 outcomes, were included in this review. Seventeen biomechanical outcomes, primarily spatiotemporal parameters, were meta-analyzed. The validity and reliability of step and stride times were found to be excellent. Similarly, the validity and reliability of step and stride length, as well as swing and stance time, were found to be good to excellent. Alternatively, spatiotemporal parameter variability and symmetry displayed poor to moderate validity and reliability. IMUs were also found to display moderate reliability for the assessment of local dynamic stability during walking. The remaining biomechanical outcomes were qualitatively summarized to provide a variety of recommendations for future IMU research.

Concurrent Validity, Test-Retest Reliability, and Sensitivity to Change of a Single Body-Fixed Sensor for Gait Analysis during Rollator-Assisted Walking in Acute Geriatric Patients

“…In contrast to the basic gait parameters of gait speed, cadence, step time, step length, and walk ratio, the levels of agreement for estimates of symmetry and variability between the DynaPort MT and the Mobility Lab were only poor to moderate (step time asymmetry: ICC = 0.29, step time variability, ICC = 0.68). This finding is similar to those reported in a recent systematic review on the validity and reliability of BFS systems for gait analysis in healthy adults, which identified spatio-temporal symmetry and variability parameters obtained from BFS systems to be less valid compared to spatio-temporal mean parameters [ 27 ]. Notably, there is, however, one study included showing excellent concurrent validity for the step time variability measured with a similar single BFS (DynaPort MiniMod) over separate walking trials (ICC = 0.88–0.94) [ 37 ].…”

“…As the validity of gait variability outcomes has been reported to improve with multiple walking trials [ 75 ], this test procedure may have improved these findings. In general, parameters addressing gait symmetry and variability based on individual footstep data have been discussed to be, by definition, more susceptible to random measurement errors from step to step as gait parameters on averaged footstep data which may mask such potential errors [ 27 ].…”

“…In recent years, such BFS systems have become a common alternative to the expensive and strictly lab-based methods for comprehensive gait analysis in laboratory, clinical, and daily living environments [ 18 , 19 , 21 , 25 , 26 ]. An increasing number of studies also indicate that BFS systems are valid and reliable for quantifying spatio-temporal gait parameters in healthy older adults (for review see [ 27 ]) and different patient populations (e.g., individuals with Parkinson’s disease and other neurological disorders [ 28 , 29 , 30 , 31 , 32 ], mild cognitive impairment [ 29 ], lower-limb prosthesis [ 33 ], or hip osteoarthritis and total hip replacement [ 34 ]). Although BFS systems have already been used for gait analysis in older adults during walking with a rollator (for review see, [ 35 ]), there is limited evidence on their psychometric properties for quantifying spatio-temporal gait parameters (e.g., gait speed, cadence, step time, or step length) under this walking condition.…”

Gait Disorders in Older Adults - A Structured Review and Approach to Clinical Assessment

“…Since the turn of the century, the use of body-worn inertial sensors to assess gait (so-called inertialocography) has grown tremendously [89,90]. The methodology however remains plagued by numerous problems among which are the wide variety of protocols, absence of normative values and the basic fact that the local coordinates of the devices are not aligned with any physiologically meaningful axis.…”

Interpretability of Input Representations for Gait Classification in Patients after Total Hip Arthroplasty

“…With modern movement tracking systems, a huge amount of data is available (big data) [3,4]. The progressive development of motion analysis systems based on inertial measurement units (IMUs) contributes in particular to the generation of large amounts of data, because they make valid and reliable biomechanical data easily accessible [5]. This provides the potential to generate new knowledge and a better understanding of human biomechanics.…”