title: Development and validation of an accelerometer-based method for quantifying gait events.
abstract: An original signal processing algorithm is presented to automatically extract, on a stride-by-stride basis, four consecutive fundamental events of walking, heel strike (HS), toe strike (TS), heel-off (HO), and toe-off (TO), from wireless accelerometers applied to the right and left foot. First, the signals recorded from heel and toe three-axis accelerometers are segmented providing heel and toe flat phases. Then, the four gait events are defined from these flat phases. The accelerometer-based event identification was validated in seven healthy volunteers and a total of 247 trials against reference data provided by a force plate, a kinematic 3D analysis system, and video camera. HS, TS, HO, and TO were detected with a temporal accuracy ± precision of 1.3 ms ± 7.2 ms, -4.2 ms ± 10.9 ms, -3.7 ms ± 14.5 ms, and -1.8 ms ± 11.8 ms, respectively, with the associated 95% confidence intervals ranging from -6.3 ms to 2.2 ms. It is concluded that the developed accelerometer-based method can accurately and precisely detect HS, TS, HO, and TO, and could thus be used for the ambulatory monitoring of gait features computed from these events when measured concurrently in both feet.
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium; INTELSIG Laboratory, Department of Electrical Engineering and Computer Science, ULg, Liège, Belgium. Electronic address: mboutaayamou@ulg.ac.be.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Boutaayamou
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
authors.forename: Cédric
authors.initials: C
authors.lastname: Schwartz
authors.affiliation: ICTEAM Institute, Catholic University of Leuven, Louvain-la-Neuve, Belgium; Movere Group, Cyclotron Research Center, ULg, Liège, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: Stamatakis
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
authors.forename: Vincent
authors.initials: V
authors.lastname: Denoël
authors.affiliation: Department of Motricity Sciences, ULg, Liège, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Maquet
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Forthomme
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Croisier
authors.affiliation: ICTEAM Institute, Catholic University of Leuven, Louvain-la-Neuve, Belgium.
authors.forename: Benoît
authors.initials: B
authors.lastname: Macq
authors.affiliation: INTELSIG Laboratory, Department of Electrical Engineering and Computer Science, ULg, Liège, Belgium.
authors.forename: Jacques G
authors.initials: JG
authors.lastname: Verly
authors.affiliation: Movere Group, Cyclotron Research Center, ULg, Liège, Belgium; Department of Neurology, University Hospital Center, Liège, Belgium.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Garraux
authors.affiliation: Laboratory of Human Motion Analysis, University of Liège (ULg), Liège, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Brüls
mesh_terms: D061725:Accelerometry / Q000295:instrumentation* / Q000592:standards; D000328:Adult; D000465:Algorithms; D001696:Biomechanical Phenomena; D005528:Foot / Q000502:physiology; D005684:Gait; D006801:Humans; D012015:Reference Standards; D012815:Signal Processing, Computer-Assisted; D016138:Walking
keywords: Accelerometers; Detection; Gait; Gait cycle; Gait event; Gait phases; Heel strike; Heel-off; Signal processing; Toe strike; Toe-off; Validation; Walking