New Lower-Limb Gait Asymmetry Indices Based on a Depth Camera

Background: Various asymmetry indices have been proposed to compare the spatiotemporal, kinematic and kinetic parameters of lower limbs during the gait cycle. However, these indices rely on gait measurement systems that are costly and generally require manual examination, calibration procedures and the precise placement of sensors/markers on the body of the patient. Methods: To overcome these issues, this paper proposes a new asymmetry index, which uses an inexpensive, easy-to-use and markerless depth camera (Microsoft Kinect™) output. This asymmetry index directly uses depth images provided by the Kinect™ without requiring joint localization. It is based on the longitudinal spatial difference between lower-limb movements during the gait cycle. To evaluate the relevance of this index, fifteen healthy subjects were tested on a treadmill walking normally and then via an artificially-induced gait asymmetry with a thick sole placed under one shoe. The gait movement was simultaneously recorded using a Kinect™ placed in front of the subject and a motion capture system. Results: The proposed longitudinal index distinguished asymmetrical gait (p < 0.001), while other symmetry indices based on spatiotemporal gait parameters failed using such Kinect™ skeleton measurements. Moreover, the correlation coefficient between this index measured by Kinect™ and the ground truth of this index measured by motion capture is 0.968. Conclusion: This gait asymmetry index measured with a Kinect™ is low cost, easy to use and is a promising development for clinical gait analysis.

[1]  Burke Gurney,et al.  Leg length discrepancy. , 2002, Gait & posture.

[2]  S Toksvig-Larsen,et al.  Validation of a functional method for the estimation of hip joint centre location. , 1999, Journal of biomechanics.

[3]  J. Hamill,et al.  Predicting the minimal energy costs of human walking. , 1991, Medicine and science in sports and exercise.

[4]  Franck Multon,et al.  Detection of gait cycles in treadmill walking using a Kinect. , 2015, Gait & posture.

[5]  C. Cobelli,et al.  A Markerless Motion Capture System to Study Musculoskeletal Biomechanics: Visual Hull and Simulated Annealing Approach , 2006, Annals of Biomedical Engineering.

[6]  F. Prince,et al.  Symmetry and limb dominance in able-bodied gait: a review. , 2000, Gait & posture.

[7]  Andrew W. Fitzgibbon,et al.  Real-time human pose recognition in parts from single depth images , 2011, CVPR 2011.

[8]  D. Shepard A two-dimensional interpolation function for irregularly-spaced data , 1968, ACM National Conference.

[9]  S. M. N. Arosha Senanayake,et al.  Identifying gait asymmetry using gyroscopes--a cross-correlation and Normalized Symmetry Index approach. , 2011, Journal of biomechanics.

[10]  A. Nicol,et al.  A comparison of gait symmetry and hip movements in the assessment of patients with monarticular hip arthritis. , 1994, Clinical biomechanics.

[11]  Kara K. Patterson,et al.  Evaluation of gait symmetry after stroke: a comparison of current methods and recommendations for standardization. , 2010, Gait & posture.

[12]  H. S. Wolff,et al.  iRun: Horizontal and Vertical Shape of a Region-Based Graph Compression , 2022, Sensors.

[13]  K R Kaufman,et al.  Gait asymmetry in patients with limb-length inequality. , 1996, Journal of pediatric orthopedics.

[14]  A. Bhave,et al.  Improvement in gait parameters after lengthening for the treatment of limb-length discrepancy. , 1999, The Journal of bone and joint surgery. American volume.

[15]  Kelly J. Bower,et al.  Concurrent validity of the Microsoft Kinect for assessment of spatiotemporal gait variables. , 2013, Journal of biomechanics.

[16]  Sander Oude Elberink,et al.  Accuracy and Resolution of Kinect Depth Data for Indoor Mapping Applications , 2012, Sensors.

[17]  Marjorie Skubic,et al.  Unobtrusive, Continuous, In-Home Gait Measurement Using the Microsoft Kinect , 2013, IEEE Transactions on Biomedical Engineering.

[18]  U. Croce,et al.  A kinematic and kinetic comparison of overground and treadmill walking in healthy subjects. , 2007, Gait & posture.

[19]  Sandra J. Olney,et al.  Role of symmetry in gait performance of stroke subjects with hemiplegia , 1995 .

[20]  Alexandra Pfister,et al.  Comparative abilities of Microsoft Kinect and Vicon 3D motion capture for gait analysis , 2014, Journal of medical engineering & technology.

[21]  L. Döderlein,et al.  Gait asymmetries in children with cerebral palsy: do they deteriorate with running? , 2012, Gait & posture.

[22]  B. Auvinet,et al.  Reference data for normal subjects obtained with an accelerometric device. , 2002, Gait & posture.

[23]  Nitish V. Thakor IEEE Transactions on Neural Systems and Rehabilitation Engineering: Editorial , 2006 .

[24]  Hartmut Witte,et al.  ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion--part I: ankle, hip, and spine. International Society of Biomechanics. , 2002, Journal of biomechanics.