A promising but still scarcely explored strategy for the estimation of gait parameters based on inertial sensors involves the adoption of machine learning techniques. However, existing approaches are reliable only for specific conditions, inertial measurements unit (IMU) placement on the body, protocols, or when combined with additional devices. In this paper, we tested an alternative gait-events estimation approach which is fully data-driven and does not rely on a priori models or assumptions. High-frequency (512 Hz) data from a commercial inertial unit were recorded during 500 steps performed by 40 healthy participants. Sensors’ readings were synchronized with a reference ground reaction force system to determine initial/terminal contacts. Then, we extracted a set of features from windowed data labeled according to the reference. Two gray-box approaches were evaluated: (1) classifiers (decision trees) returning the presence of a gait event in each time window and (2) a classifier discriminating between stance and swing phases. Both outputs were submitted to a deterministic algorithm correcting spurious clusters of predictions. The stance vs. swing approach estimated the stride time duration with an average error lower than 20 ms and confidence bounds between ±50 ms. These figures are suitable to detect clinically meaningful differences across different populations.

Machine-learning based determination of gait events from foot-mounted inertial units / M. Zago, M. Tarabini, M.D. Spiga, C. Ferrario, F. Bertozzi, C. Sforza, M. Galli. - In: SENSORS. - ISSN 1424-8220. - 21:3(2021), pp. 839.1-839.13. [10.3390/s21030839]

Machine-learning based determination of gait events from foot-mounted inertial units

M. Zago
Primo
;
F. Bertozzi;C. Sforza
Penultimo
;
2021

Abstract

A promising but still scarcely explored strategy for the estimation of gait parameters based on inertial sensors involves the adoption of machine learning techniques. However, existing approaches are reliable only for specific conditions, inertial measurements unit (IMU) placement on the body, protocols, or when combined with additional devices. In this paper, we tested an alternative gait-events estimation approach which is fully data-driven and does not rely on a priori models or assumptions. High-frequency (512 Hz) data from a commercial inertial unit were recorded during 500 steps performed by 40 healthy participants. Sensors’ readings were synchronized with a reference ground reaction force system to determine initial/terminal contacts. Then, we extracted a set of features from windowed data labeled according to the reference. Two gray-box approaches were evaluated: (1) classifiers (decision trees) returning the presence of a gait event in each time window and (2) a classifier discriminating between stance and swing phases. Both outputs were submitted to a deterministic algorithm correcting spurious clusters of predictions. The stance vs. swing approach estimated the stride time duration with an average error lower than 20 ms and confidence bounds between ±50 ms. These figures are suitable to detect clinically meaningful differences across different populations.
Decision trees; Gait analysis; Spatio-temporal parameters; Wearable sensors
Settore BIO/16 - Anatomia Umana
Settore M-EDF/02 - Metodi e Didattiche delle Attivita' Sportive
Settore ING-INF/06 - Bioingegneria Elettronica e Informatica
   PIANO DI SOSTEGNO ALLA RICERCA 2015-2017 - LINEA 2 "DOTAZIONE ANNUALE PER ATTIVITA' ISTITUZIONALE"
   UNIVERSITA' DEGLI STUDI DI MILANO
2021
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/810966
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