A multi-sensor wearable system for gait assessment in real-world conditions: performance in individuals with impaired mobility

Abstract

Accurately assessing people’s gait, especially in real-world conditions and in case of impaired mobility, is still a challenge due to intrinsic and extrinsic factors resulting in gait complexity. To improve the estimation of gait-related digital mobility outcomes (DMOs) in real-world scenarios, this study presents a wearable multi-sensor system (INDIP), integrating complementary sensing approaches (two plantar pressure insoles, three inertial units and two distance sensors). The INDIP technical validity was assessed against stereophotogrammetry during a laboratory experimental protocol comprising structured tests (including continuous curvilinear and rectilinear walking and steps) and a simulation of daily-life activities (SDA, including intermittent gait and short walking bouts). To evaluate its performance on various gait patterns, data were collected on 128 participants from seven cohorts: healthy young and older adults, patients with Parkinson’s disease, multiple sclerosis, chronic obstructive pulmonary disease, congestive heart failure, and proximal femur fracture. Moreover, INDIP usability was evaluated by recording 2.5-hours of real-world unsupervised activity. Excellent absolute agreement (ICC > 0.95) and very limited mean absolute errors were observed for all cohorts and DMOs (cadence ≤ 0.61 steps/min, stride length ≤ 0.02 m, walking speed ≤ 0.02 m/s) in the structured tests. Larger, but limited, errors were observed during the SDA (cadence 2.72–4.87 steps/min, stride length 0.04–0.06 m, walking speed 0.03–0.05 m/s). Neither major technical nor usability issues were declared during the 2.5-hours acquisitions. Therefore, the INDIP system can be considered a valid and feasible solution to collect reference data for analyzing gait in real-world conditions.

Estimating real-world walking speed from a single wearable device: analytical pipeline, results and lessons learnt from the Mobilise-D technical validation study

“…Utilisation of the INDIP system as a reference during both the laboratory-based and real-world protocol proved to be successful in overcoming limitations in accuracy, battery life and usability, all of which are common restrictions of real-world reference systems previously adopted in the literature (e.g., wearable camera and GNNS systems 36,39 ). Speci cally, the INDIP system has been validated showing excellent agreement (ICC > 0.95) and very low MAEs (simulated daily activities = ≤ 0.05 m/s) against a stereophotogrammetric system in the same cohorts and laboratory protocol as in the present study 31 .…”

“…Pressure insoles were selected for each participant's foot size and inserted into the shoe. The INDIP system has been validated in previous studies across a range of conditions and in this TVS cohorts also, showing excellent results and reliability in the quali cation of mobility outcomes (MAE laboratory ≤ 0.02 m/s, simulated daily activities = 0.03 to 0.05 m/s), a complete overview of the validation results can be found in 31 . The INDIP and the wearable device were synchronised using their timestamps (± 10 ms).…”

“…The aim of this study was to provide a comprehensive validation of walking speed estimated from a single inertial measurement unit based wearable device against a multi-sensor reference system integrating pressure insoles (INDIP) [29][30][31] , to enable a robust validation: (i) in both laboratory and realworld settings, (ii) across different clinical cohorts with a range of mobility disabilities, (iii) across gait tasks of varying complexity and (iv) accounting for confounding factors (walking bout (WB) duration and walking speed). Subsequently, we provide recommendations for the suitability of a wearable device paired with the proposed analytical pipeline as a measure of real-world mobility and suggest a framework for future studies aiming to validate DMOs for real-world monitoring.…”

Gait Monitoring and Analysis: A Mathematical Approach

“…To compare our solution with what was provided by other studies, we need to use our devices and the devices from other studies with the same people. For this reason, we are writing a project with researchers of Politecnico of Turin where we will compare our solutions with their solutions described in the paper [ 8 ]. In these new experiments, we plan to improve the accuracy of our solution by also taking advantage of a gyroscope sensor.…”

“…In particular, a study proposed by the Politecnico di Torino [ 8 ] employs shoes with sensorized insoles and a chest-mounted device, both used to record data in a controlled laboratory setting. Other studies adopt video-based solutions [ 9 ] or different kinds of external systems, such as sensorized walkways [ 10 ].…”