Objective gait analysis in the horse: the use of distal limb mounted Inertial Measurement Unit sensors for early (objective) quantification of induced incoordination. Part 1: Effect of detomidine on kinematic variables at walk.

Abstract

Reasons for performing study: Inertial Measurement Unit (IMU) sensor based techniques are becoming more popular as a tool for objective locomotor assessment in horses. Using currently proposed methods, only limited information is available for the quantification of neurological gait abnormalities (i.e. ataxia). Objective: To quantify the change in kinematic variables using limb mounted IMU sensors in neurologically sound horses on a straight line at walk before and after induction of transient ataxia and to evaluate which gait parameters can be used to detect incoordination in horses. Materials & Methods: The walk and trot of a group of (n=7) horses were kinematically evaluated using IMU sensors before and after ataxia induction. Ataxia was induced by intravenous administration of a sedative agent (Detomidine HCL). Horses were instrumented with eight IMU sensors; four were attached to the lateral aspect of the III metacarpal/metatarsal bone of each limb using brush boots, and the other four were attached to the upper body: head, withers, sternum, and tuber sacrale. Statistical analysis was performed using a linear mixed model with significance set at P<0.05. Results: There was a significant increase in stance, swing, and stride duration after the administration of sedation. The maximum protraction, retraction, adduction, and abduction were not significantly different before and after sedation. Conclusion: Stance, swing and stride duration increase after administration of a sedative agent. The maximum protraction, retraction, adduction, and abduction are variables that don’t seem to be of great value for quantification of neurological deficits in horses with induced ataxia using this model. More research is needed to rule out the effects of speed changes after the sedation which may affect the quantification of these variables for induced incoordination. Ethical Animal Research: The local ethics committee approved the study in compliance with the Dutch Act on Animal Experimentation.