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.

Towards Real-Time Detection of Gait Events on Different Terrains Using Time-Frequency Analysis and Peak Heuristics Algorithm

“…Signals acquired from ground reaction force (GRF) and optoelectronic motion capture have been widely used for the detection of TO and HS events in previous studies [8,9]. A major limitation of these systems is that they are expensive and restricted to a controlled laboratory environment [10]. To overcome these drawbacks, various wearable sensors have been developed for gait event detection [11].…”

Validation of temporal gait metrics from three IMU locations to the gold standard force plate

“…This is because the zero movement during ground contact can be used to reduce integration times to result in more accurate distance estimations [21]. Recent research has also shown how detailed gait events can be found using an inertial sensor on the heel and on the toe [23].…”

Human Gait Kinematic Measurement

“…The accelerometers can sense the direction of gravity, delivering a unique combination of. the three directions for each position [27] [28]. The measured information is received in the computer in a particular format.…”

“…In general, the first two have the same problems in being computationally and economically expensive, and they often require a sophisticated clinical laboratory [21] [22]. On the other hand, wearable sensors, e.g., accelerometers (such as those used in this work), have the following advantages without losing precision in the measurement: they are small and inexpensive, have low-computational cost, are easy to adjust, and can perform measurements in any environment [23]- [28].…”