Validity and repeatability of inertial measurement units for measuring gait parameters

Abstract

Inertial measurement units (IMUs) are small wearable sensors that have tremendous potential to be applied to clinical gait analysis. They allow objective evaluation of gait and movement disorders outside the clinic and research laboratory, and permit evaluation on large numbers of steps. However, repeatability and validity data of these systems are sparse for gait metrics. The purpose of this study was to determine the validity and between-day repeatability of spatiotemporal metrics (gait speed, stance percent, swing percent, gait cycle time, stride length, cadence, and step duration) as measured with the APDM Opal IMUs and Mobility Lab system. We collected data on 39 healthy subjects. Subjects were tested over two days while walking on a standard treadmill, split-belt treadmill, or overground, with IMUs placed in two locations: both feet and both ankles. The spatiotemporal measurements taken with the IMU system were validated against data from an instrumented treadmill, or using standard clinical procedures. Repeatability and minimally detectable change (MDC) of the system was calculated between days. IMUs displayed high to moderate validity when measuring most of the gait metrics tested. Additionally, these measurements appear to be repeatable when used on the treadmill and overground. The foot configuration of the IMUs appeared to better measure gait parameters; however, both the foot and ankle configurations demonstrated good repeatability. In conclusion, the IMU system in this study appears to be both accurate and repeatable for measuring spatiotemporal gait parameters in healthy young adults.

Accuracy Verification of Spatio-Temporal and Kinematic Parameters for Gait Using Inertial Measurement Unit System

“…This previous study was conducted using a standard treadmill, a split-belt treadmill, and over the ground, and gait pattern data measured by the IMU system were verified using standard clinical procedures. The authors suggested that gait analysis using the IMU system offered a suitable means of accurately measuring Spatio-temporal parameters of gait pattern [17].…”

“…For measuring the position data, the IMU system uses a similar analysis related to Wavelets to visualize gait identification [14][15][16]. Nevertheless, despite this shortcoming, the advantages of IMU systems are that they are increasingly utilized in industry and for medical diagnostic purposes [17,18]. Several previous studies of gait analysis reported the diagnostic significance of the IMU system by comparing the IMU system and the OMC system [10,19].…”

Independent and sensitive gait parameters for objective evaluation in knee and hip osteoarthritis using wearable sensors

“…Gait parameters were initially selected based on their reliability 25 , theoretical considerations, and completeness (<20% missing values). With regard to theoretical considerations, the following decisions were made: 1) in case gait parameters reflected the same outcome (e.g.…”

Towards ecologically valid biomarkers: real-life gait assessment in cerebellar ataxia

“…decreased walking speed), but features inherent to ataxic gait changes in DCA-as it will be these features that will be particularly sensitive to change by upcoming treatment trials specifically targeting cerebellar Out of the respective total groups, 21 CA patients and 17 HC were available for the RLW condition (for an overview of these subjects, see Table 1). Step events, as well as spatio-temporal gait parameters from the IMU sensors were extracted using APDM's mobility lab software (Version 2) 31 , which has been shown to deliver good-to-excellent accuracy and repeatability 32,33 . For each detected stride, the following features were extracted: stride length, stride time, lateral step deviation and raw accelerometer data of the lumbar sensor.…”