title: Heel and toe clearance estimation for gait analysis using wireless inertial sensors.
abstract: Tripping is considered a major cause of fall in older people. Therefore, foot clearance (i.e., height of the foot above ground during swing phase) could be a key factor to better understand the complex relationship between gait and falls. This paper presents a new method to estimate clearance using a foot-worn and wireless inertial sensor system. The method relies on the computation of foot orientation and trajectory from sensors signal data fusion, combined with the temporal detection of toe-off and heel-strike events. Based on a kinematic model that automatically estimates sensor position relative to the foot, heel and toe trajectories are estimated. 2-D and 3-D models are presented with different solving approaches, and validated against an optical motion capture system on 12 healthy adults performing short walking trials at self-selected, slow, and fast speed. Parameters corresponding to local minimum and maximum of heel and toe clearance were extracted and showed accuracy ± precision of 4.1 ± 2.3 cm for maximal heel clearance and 1.3 ± 0.9 cm for minimal toe clearance compared to the reference. The system is lightweight, wireless, easy to wear and to use, and provide a new and useful tool for routine clinical assessment of gait outside a dedicated laboratory.
authors.affiliation: Laboratory of Movement Analysis and Measurements, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. benoit.mariani@epfl.ch
authors.forename: Benoit
authors.initials: B
authors.lastname: Mariani
authors.forename: Stephane
authors.initials: S
authors.lastname: Rochat
authors.forename: Christophe J
authors.initials: CJ
authors.lastname: Büla
authors.forename: Kamiar
authors.initials: K
authors.lastname: Aminian
mesh_terms: D061725:Accelerometry / Q000295:instrumentation* / Q000379:methods; D000328:Adult; D000465:Algorithms; D005260:Female; D005684:Gait / Q000502:physiology*; D006365:Heel / Q000502:physiology; D006801:Humans; D008297:Male; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D014034:Toes / Q000502:physiology; D059015:Wireless Technology / Q000295:instrumentation*