Use of a wireless, inertial sensor-based system to objectively evaluate flexion tests in the horse
Article first published online: 27 NOV 2012
© 2012 EVJ Ltd
Equine Veterinary Journal
Special Issue: 58th Annual Convention of the American Association of Equine Practitioners. Guest Editors: N. White, D. Sellon and B. Ball. Publication of this supplement was supported by the American Association of Equine Practitioners
Volume 44, Issue Supplement S43, pages 8–11, December 2012
How to Cite
Marshall, J. F., Lund, D. G. and Voute, L. C. (2012), Use of a wireless, inertial sensor-based system to objectively evaluate flexion tests in the horse. Equine Veterinary Journal, 44: 8–11. doi: 10.1111/j.2042-3306.2012.00611.x
- Issue published online: 27 NOV 2012
- Article first published online: 27 NOV 2012
- Received: 29.02.12; Accepted: 06.06.12
- flexion test
Objectives: A wireless, inertial sensor-based system has previously been validated for evaluation of equine lameness. However, threshold values have not been determined for the assessment of responses to flexion tests. The aim of this investigation was to evaluate a sensor-based system for objective assessment of the response to flexion.
Methods: Healthy adult horses (n = 17) in work were recruited prospectively. Horses were instrumented with sensors on the head (accelerometer), pelvis (accelerometer) and right forelimb (gyroscope), before trotting in a straight line (minimum 25 strides) for 2 consecutive trials. Sensors measured 1) vertical pelvic movement asymmetry (PMA) for both right and left hindlimb strides and 2) average difference in maximum and minimum pelvic height (PDMax and PDMin) between right and left hindlimb strides in millimetres. A hindlimb was randomly selected for proximal flexion (60 s), after which the horse trotted a minimum of 10 strides. Response to flexion was blindly assessed as negative or positive by an experienced observer. Changes in PMA, PDMax and PDMin between baseline and flexion examinations were calculated for each test. Statistical analysis consisted of a Pearson's product moment test and linear regression on baseline trials, Mann–Whitney rank sum test for effect of flexion and receiver operator curve (ROC) analysis of test parameters.
Results: There was a strong correlation between trials for PMA, PDMin and PDMax measurements (P<0.001). A positive flexion test resulted in a significant increase in PMA (P = 0.021) and PDMax (P = 0.05) only. Receiver–operator curve analysis established cut-off values for change in PMA and PDMax of 0.068 and 4.47 mm, respectively (sensitivity = 0.71, specificity = 0.65) to indicate a positive response to flexion.
Conclusions: A positive response to flexion resulted in significant changes to objective measurements of pelvic symmetry.
Potential relevance: Findings support the use of inertial sensor systems to objectively assess response to flexion tests. Further investigation is warranted to establish cut-off values for objective assessment of other diagnostic procedures.