Use of sample entropy to study equine gait lameness.

Abstract

Administration of a sedative is occasionally required to perform a nerve or joint block in the horse during the course of a lameness examination. Because sedatives have analgesic properties, we investigated as to whether a sedative could ameliorate lameness. An improvement in gait after administration of a sedative could erroneously be attributed to a nerve or joint block performed at the same time. This study used a computerized gait analysis system (Lameness Locator) to objectively examine the effects of the sedative detomidine on the gait of naturally lame horses. The gait analysis system measures symmetry of motion. Sound horses have a symmetrical gait at the trot and lameness causes asymmetry, which is detected and quantified by the Lameness Locator. We utilized calculation of Sample Entropy to determine the complexity of system. The horses were trotted in a straight line and evaluated using inertial sensors. A trend in dynamic stability was observed with calculation of Sample Entropy of recorded head and pelvic acceleration data. At first the study between the lame and sound horse proved increase in sample entropy. Stability was unaffected after administration of sedatives, which is shown by statistically insignificant entropy value change.