SYSTEM AND METHOD FOR 3D GAIT ASSESSMENT

• US 20130123665A1
• Filed: 05/25/2011
• Published: 05/16/2013
• Est. Priority Date: 07/14/2010
• Status: Active Grant

• Current Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Original Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Inventors: Aminian, Kamiar, Mariani, Benot
• Granted Patent: US 9,307,932 B2
• Time in Patent Office: Days
• US Class Current: 600/592
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A61B 5/112 Gait analysis
• CPC Class Codes: A61B 5/6807 Footwear
• CPC Class Codes: A61B 5/6829 Foot or ankle
• CPC Class Codes: A61B 5/7242 using integration

Abstract

The invention relates to a system and a method for assessment of walking and miming gait in human. The method is preferably based on the fusion of a portable device featuring inertial sensors and several new dedicated signal processing algorithms: the detection of specific temporal events and parameters, 5 optimized fusion and de-drifted integration of inertial signals, automatic and online virtual alignment of sensors module, 3D foot kinematics estimation, a kinematic model for automatic online heel and toe position estimation, and finally the extraction of relevant and clinically meaning-full outcome parameters. Advantageously including at least one wireless inertial module attached to foot, the system provides common spatio-temporal parameters (gait cycle time, stride length, and stride velocity), with the 10 advantage of being able to work in unconstrained condition such as during turning or running. It furthermore may provide original parameters for each gait cycle, both temporal (load, foot-flat and push duration) and spatial (foot clearance and turning angle), and their inter-cycles variability. The system and method according to the invention allows the assessment of various aspects of gait which have shown recently to be of premium importance in research and clinical field, including foot clearance, 15 turns, gait initiation and termination, running, or gait variability. The system may be light weight, easy to wear and use, and suitable for any application requiring objective and quantitative evaluation of gait without heavy laboratory settings.

Claims

1. Method and dedicated algorithm based on sensor fusion and foot kinematics, for the 3D gait assessment using at least one inertial sensor fixed to the foot or integrated on a shoe;

said method taking into consideration at least one of the following foot parameters obtained from said sensor(s);

turning

spatial

clearance

temporal

2. Method according to claim 1 comprising the variability measurement of said parameters.

3. Method according to claim 1 taking into consideration at least said turning and said clearance parameters.

4. Method according to claim 1 wherein said temporal parameters are derived from temporal events of gait detected by said sensor(s), said temporal events being based on mathematical transformation of angular velocity and acceleration signals and including active or static periods, heel-strike, toe-strike, motion-less, heel-off, toe-off and midswing.

5. Method according to claim 1 wherein said temporal parameters are derived from temporal events of gait detected by said sensor(s), said temporal events being based on at least one of the following parameters:

load, foot-flat, push, swing and stance duration, as well as double-support when both feet features a sensing module.

6. Method according to claim 1 furthermore comprising the determination of the 3D foot kinematics (position and orientation) during human gait locomotion, including straight walking, turning, walking on uneven terrain, stairs, ramp, running, or any combination of those activities.

7. Method according to claim 1 wherein said spatial parameters are extracted at each gait cycle from temporal events and foot kinematics, including 3D foot trajectory, stride length, stride velocity, and foot clearance.

8. Method according to claim 1 furthermore using a kinematic model providing position of heel and toe during gait from combination of temporal events and the trajectory of another point on foot.

9. Method according to claim 1 furthermore quantifying said clearance parameter from spatial trajectories of sensor, heel or toe during gait at each cycle, including minimum and maximum of toe and heel clearance.

10. Method according to claim 1 furthermore quantifying said turning parameter during gait from spatial orientation of the foot and temporal events, including turning angle.

11. Method according to claim 1 furthermore taking into consideration the stride-so-stride variability of a gait parameters time series with removing of turning outliers.

15. A method according to claim 4 based on function generation between said temporal events for modeling and compensating inertial sensors drift.

12. A wearable system for the 3D gait assessment comprising one sensor adapted to be fixed to a foot or integrated on a shoe;

said system furthermore being adapted to measure at least one of the following foot parameters;

turning

spatial

clearance

temporal

13. System according to claim 12 comprising a 6 degree of freedom inertial sensor.

14. A method using a system as defined in claim 12 and comprising a 3D alignment of said system relative to user'"'"'s gait frame.