Comparing Inertial Measurement Units to Markerless Video Analysis for Movement Symmetry in Quarter Horses

Abstract

Background: With an increasing number of systems for quantifying lameness-related movement asymmetry, between-system comparisons under non-laboratory conditions are important for multi-centre or referral-level studies. This study compares an artificial intelligence video app to a validated inertial measurement unit (IMU) gait analysis system in a specific group of horses. Methods: Twenty-two reining Quarter horses were equipped with nine body-mounted IMUs while being videoed with a smartphone app. Both systems quantified head and pelvic movement symmetry during in-hand trot (hard/soft ground) and on the lunge (left/right rein, soft ground). Proportional limits of agreement (pLoA) were established. Results: Widths of pLoA were larger for head movement (29% to 50% in-hand; 22% to 38% on lunge) than for pelvic movement (13% to 24% in-hand; 14% to 24% on lunge). Conclusion: The between-system pLoAs exceed current “lameness thresholds” aimed at identifying the affected limb(s) in lame horses. They also exceed published limits of agreement for stride-matched data but are similar to repeatability values and “lameness thresholds” from “non-lame” horses. This is encouraging for multi-centre studies and referral-level veterinary practice. The narrower pLoA values for pelvic movement asymmetry are particularly encouraging, given the difficulty of grading hind limb lameness “by eye”.

Objective Assessment of Equine Locomotor Symmetry Using an Inertial Sensor System and Artificial Intelligence: A Comparative Study

“…This system is intended for the assessment of lameness/asymmetry and can be easily used in a clinical setting to aid in the decision-making process [ 33 , 34 ]. In this study, our aim was to compare a commercial IMU system, previously validated and widely used [ 13 , 17 , 18 , 22 , 38 , 39 ], with this new system (AI-MTS) [ 33 , 34 , 40 ] in clinically sound horses and in horses with a mild intensity lameness, under different assessment conditions, i.e., a straight line and in right and left circles, on both hard and soft surfaces.…”