Lameness is the most common medical problem of horses and has a high economic cost.1 Lameness evaluation typically includes observation of a horse in motion and subjective grading of the severity of a lameness via a scoring method, such as the AAEP lameness grading scale.2 Objective methods of lameness evaluation may increase sensitivity for detection of lameness in horses and may eliminate bias during assessment of gait changes following performance of diagnostic blocks or administration of treatments.
Inertial sensors are commonly used in the aerospace and automotive industries for navigation and stabilization of vehicles. Microelectromechanical systems (ie, MEMS) inertial sensors are small devices with mechanical and electrical components that measure acceleration (accelerometers) or angular velocity (gyroscopes). Body-mounted devices with such inertial sensors have been used for evaluation of lameness in horses.3–7 Vertical movement of the head and torso of a horse can be measured with such devices; head and torso movements of horses can affect and be affected by vertical ground reaction forces of limbs.8 Asymmetry of vertical head and torso movements between right and left portions of a stride can be quantified, and associations between such data and severity of lameness in horses can be determined.3,9–11 Because of their small size and potential for wireless transmission of data, body-mounted inertial sensor devices are being commercially developed for objective evaluation of lameness in horses. Potentially, such devices could be routinely used by equine practitioners in the field for evaluation of lameness in horses.
The objective of the study reported here was to compare data obtained with an inertial sensor system7 with results of subjective lameness examinations performed by 3 experienced equine veterinarians for evaluation of lameness in horses. We hypothesized that data obtained by use of an inertial sensor system would be correlated with results of subjective lameness examinations performed by experienced equine veterinarians. If data obtained with an inertial sensor system and results of subjective lameness examinations of horses are strongly correlated, then threshold values of inertial sensor measures for detection of lameness in horses can be estimated via association of such data with mean subjective lameness scores of experienced equine veterinarians.
American Association of Equine Practitioners
Mean difference in subjective lameness scores between right and left forelimbs
Mean difference in subjective lameness scores between right and left hind limbs
Difference in minimum head height between right and left portions of the stride
Difference in minimum pelvic height between right and left portions of the stride
Difference in maximum head height between right and left portions of the stride
Difference in maximum pelvic height between right and left portions of the stride
MMA7260QT, ± 1.5 to 6 g, Freescale Semiconductor, Austin, Tex.
Gyrostar ENC-03M, Murata Electronics North America, Smyrna, Ga.
EYSF1SAJJ, Taiyo Yuden Co Ltd, Tokyo, Japan.
Hyper Power Co Ltd, Shenzhen, China.
PIC18LF452/PQ(44), Microchip Technology Inc, Chandler, Ariz.
USDA. National economic cost of equine lameness, colic, and equine protozoal myeloencephalitis in the United States. Information sheet No. N348.1001. Fort Collins, Colo: USDA APHIS Veterinary Services National Health Monitoring System, 2001.
Baxter GMStashak TS. Examination for lameness. In: Baxter GM, ed. Adams and Stashak's lameness in horses. 6th ed. Chichester, West Sussex, England: Wiley-Blackwell Publishing Ltd, 2011;118.
Weishaupt MASchatzman UStaub R. Quantification of supportive forelimb lameness by recording movements of the horse's head during exercise using an accelerometer. Pferdeheilkunde 1993; 3: 375–377.
Barrey EHermerlin MVaudelin JL, et al. Utilisation of an accelerometric device in equine gait analysis. Equine Vet J 1994; 26(suppl 17):7–12.
Pfau TRobilliard JWeller R, et al. Assessment of mild hindlimb lameness during over ground locomotion using linear discriminant analysis of inertial sensor data. Equine Vet J 2008; 38: 407–413.
Church EEWalker AMWilson AM, et al. Evaluation of discriminant analysis based on dorsoventral symmetry indices to quantify hindlimb lameness during over ground locomotion in the horse. Equine Vet J 2009; 41: 304–308.
Keegan KGKramer JYonezawa Y, et al. Assessment of repeatability of a wireless, inertial sensor-based lameness evaluation system for horses. Am J Vet Res 2011; 72: 1156–1163.
Weishaupt MAWiestner THogg HP, et al. Compensatory load redistribution of horses with induced weightbearing hindlimb lameness trotting on a treadmill. Equine Vet J 2004; 36: 727–733.
Buchner HHSavelberg HHSchamhardt HC, et al. Head and trunk movement adaptations in horses with experimentally induced fore- or hindlimb lameness. Equine Vet J 1996; 28: 71–76.
Keegan KGPai PFWilson DA, et al. Signal decomposition method of evaluating head movement to measure induced forelimb lameness in horses trotting on a treadmill. Equine Vet J 2001; 33: 446–451.
Kramer JKeegan KGKelmer G, et al. Objective determination of pelvic movement during hind limb lameness by use of a signal decomposition method and pelvic height differences. Am J Vet Res 2004; 65: 741–747.
Keegan KGMacAllister CGWilson DA, et al. Comparison of an inertial sensor system with a stationary force plate for evaluation of horses with bilateral forelimb lameness. Am J Vet Res 2012; 73: 368–374.
Keegan KGDent EVWilson DA, et al. Repeatability of subjective evaluation of lameness in horses. Equine Vet J 2010; 42: 92–97.
Keegan KGWilson DAWilson DJ, et al. Evaluation of mild lameness in horses trotting on a treadmill by clinicians and interns or residents and correlation of their assessments with kinematic gait analysis. Am J Vet Res 1998; 59: 1370–1377.
Hewetson MChristley RMHunt ID, et al. Investigations of the reliability of observational gait analysis for the assessment of lameness in horses. Vet Rec 2006; 158: 852–858.
Fuller CJBladon BMDriver AJ, et al. The intra- and inter-assessor reliability of measurement of functional outcome by lameness scoring in horses. Vet J 2006; 171: 281–286.