Quantitative sensory testing of the equine face.

Kata O. Veres‐Nyéki,Claudia Spadavecchia,Gábor Bodó,József Nyéki

doi:10.1111/evj.13270

Kata O. Veres‐Nyéki, Claudia Spadavecchia + Show 2 more

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https://doi.org/10.1111/evj.13270

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Abstract

Quantitative sensory testing methods are now standard in the evaluation of sensory function in man, while few normal equine values have been reported. The aim of this experimental study was (a) to define the tactile sensory, mechanical nociceptive and thermal nociceptive thresholds of the equine face; (b) to assess the effect of age, sex, stimulation site and shaving; (c) to evaluate the reliability of the methods and (d) to provide reference facial quantitative sensory testing values. Method description. Thirty-four healthy Warmblood horses were used in the study. Six (tactile sensory threshold) and five (mechanical nociceptive and thermal nociceptive thresholds) areas of the left side of the face with clear anatomical landmarks were evaluated. Ten horses had two (mechanical nociceptive threshold) or three (tactile sensory and thermal nociceptive thresholds) of these areas shaved for another study. A linear Mixed model was used for data analysis. All thresholds increased with age (tactile sensory threshold: by 0.90g/y (CI=[0.12g; 0.36g]) P=.001; mechanical nociceptive threshold: by 0.25N/y (CI=[0.13-0.36N]) P=.000; thermal nociceptive threshold: by 0.2°C/y (CI=[0.055-0.361]) P=.008). Sex had no effect on thresholds (tactile sensory threshold: P=.1; mechanical nociceptive threshold: P=.09; thermal nociceptive threshold: P=.2). Stimulation site affected tactile sensory and mechanical nociceptive thresholds (P=.001 and P=.008), but not thermal nociceptive threshold (P=.9). Shaving had no significant effect on any of the thresholds (tactile sensory threshold: P=.06; mechanical nociceptive threshold: P=.08; thermal nociceptive threshold: P=.09). Only the left side was investigated and measurements were obtained on a single occasion. Handheld quantitative sensory testing does not require shaving or clipping to provide reliable measurements. Stimulation over the nostril (tactile sensory threshold), temporomandibular joint (mechanical nociceptive threshold) and supraorbital foramen (thermal nociceptive threshold) resulted in the most consistent thresholds.

Highlights

Quantitative sensory testing methods are standard in the evaluation of sensory function in human subjects
Few normal equine quantitative sensory testing values based on the behavioural responses to mechanical and thermal stimuli have been reported in the literature.[6,7,8,9]
We have found that shaving did not significantly affect tactile sensory thresholds, mechanical nociceptive thresholds and thermal nociceptive thresholds on the equine face, which may facilitate the use of this technique in clinical cases

Summary

Introduction

Quantitative sensory testing methods are standard in the evaluation of sensory function in human subjects. Few normal equine quantitative sensory testing values based on the behavioural responses to mechanical and thermal stimuli have been reported in the literature.[6,7,8,9] Von Frey filaments were used in horses to evaluate skin sensitivity after branding or microchip placement[10] and to investigate the effects of epidural ketamine on wound sensitivity,[11] but there are no reported reference values for tactile sensory threshold. Objectives: The aim of this experimental study was (a) to define the tactile sensory, mechanical nociceptive and thermal nociceptive thresholds of the equine face; (b) to assess the effect of age, sex, stimulation site and shaving; (c) to evaluate the reliability of the methods and (d) to provide reference facial quantitative sensory testing values. Stimulation over the nostril (tactile sensory threshold), temporomandibular joint (mechanical nociceptive threshold) and supraorbital foramen (thermal nociceptive threshold) resulted in the most consistent thresholds

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