Evaluation of a portable media device for use in determining postural stability in standing horses

OBJECTIVE To determine the ability of an accelerometer within a commercially available portable media device (PMD) to measure changes in postural stability of standing horses during various stance conditions and to compare these results with data obtained by use of a stationary force platform. ANIMALS 7 clinically normal horses. PROCEDURES A PMD was mounted on a surcingle; the surcingle was placed immediately caudal to the highest point of the shoulders (withers). Each horse was examined while standing on a stationary force platform system in a normal square stance, forelimb base-narrow stance, and normal square stance at 5 and 10 minutes after sedation induced by IV administration of xylazine hydrochloride. A minimum of 5 trials were conducted for each stance condition. Ranges of craniocaudal and mediolateral motion as well as SDs were collected for the PMD and force platform system. Analyses were performed with mixed-model ANOVAs, and correlation coefficients were calculated. RESULTS Stance condition significantly altered craniocaudal accelerations measured by use of the PMD, all craniocaudal and mediolateral displacements of the center of pressure, and velocities measured by use of the stationary force platform. For both the PMD and force platform, SDs were significantly affected by stance condition in both craniocaudal and mediolateral directions. Correlation coefficients between the systems for all variables were low to moderate (r = 0.18 to 0.58). CONCLUSIONS AND CLINICAL RELEVANCE Body-mounted PMDs should be investigated for use in assessment of postural stability in horses with neuromuscular abnormalities.