User Independent Estimations of Gait Events with Minimal Sensor Data

Publication Date

5-1-2021

Document Type

Article

Publication Title

IEEE Journal of Biomedical and Health Informatics

Volume

25

Issue

5

DOI

10.1109/JBHI.2020.3028827

First Page

1583

Last Page

1590

Abstract

Goal: The purpose of this study was to provide an initial examination of the utility of the Beta Process - Auto Regressive - Hidden Markov Model (BP-AR-HMM) for the prior identification of gait events. A secondary objective was to determine whether the output of the model could be used for classification and prediction of locomotion states. Methods: In this study we utilized the output of the BP-AR-HMM to develop user-independent identification of gait events and gait classification from an idealized three-dimensional acceleration signal. The input acceleration data were collected from two walking (1.4 and 1.6 ms-1) and two running (2.6 and 3.0 ms-1) steady state speeds, and during two dynamic walk to run and run to walk transitions (1.8-2.4 and 2.4-1.8 ms-1) on an instrumented force treadmill. Results: The BP-AR-HMM identified 9 unique states. Of these, two states, 4 and 1, were utilized to estimate initial contact and toe off, respectively. The lead time from the first instance of state 4 to initial contact was 0.13 ± 0.02 s. Similarly, the first instance of state 1 occurred 0.14 ± 0.03 s before toe off. Two other states (3 and 7) were examined for possible utilization in a probabilistic model for the prediction of pending locomotion state transitions. Conclusion: The identification of gait events prior to their occurrence by the BP-AR-HMM appears to be an approach that can minimize the quantity of sensor data in an offline approach. Furthermore, there is evidence it could also be used as a basis to build a probabilistic model to estimate locomotion transitions.

Keywords

Accelerometry, biomechanics, Classification algorithms, Data-driven machine learning

Department

Kinesiology

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