Evaluation of the practical clinical use of the Horse Grimace Scale translated into French.

The research paper conducts a study to understand the reliability and efficiency of a French-translated version of Horse Grimace Scale in assessing pain in horses. It analyzes the variation in the scores given by both trained riders and anesthetists, with high correlation seen between their evaluations which suggests the scale’s utility regardless of the assessor’s specialization in pain management.

Research Methodology

• The study is designed as a prospective, randomized, and clinical experiment with three different groups – operated (OP), positive control (PC), and negative control (NC). The OP group included 13 horses which underwent surgery, the PC group comprised 7 colicking horses, and the NC group had 8 exercising sport horses.
• Pictures were taken beforehand and post the surgery for OP group horses, during the arrival for PC group horses, and while they were at rest in their stalls for NC group horses. These pictures were then evaluated using the French-translated Horse Grimace Scale by three anesthetists and four riders at two points, 2 weeks apart.
• The evaluation protocol was such that for each image, every evaluator provided a score ranging from 1-3 for six different identified facial action units. The scores of both groups of evaluators were compared using a data analysis tool known as the Wilcoxon test.
• To assess the reliability of the scoring system, Spearman correlation tests measured the intra- and inter-evaluator reliability, and intra-class coefficients (ICCs) were formulated.

Research Results

• The riders and anesthetists both gave significantly higher scores for the PC group as compared to the NC group. The scores of both groups were highly correlated.
• Intra-class coefficients for riders and anesthetists were 0.94 and 0.91 respectively, indicating a strong correlation between two sets of scores by the same evaluators in Evaluation 1(E1) and Evaluation 2(E2).
• The specificity of the French-translated Horse Grimace Scale (HGSfv) was 94% and sensitivity was 43%, which indicates decent accuracy at identifying true positive and true negative observations.

Research Conclusions

• The results indicate that knowledge of horses, irrespective of the specialization in veterinary anesthesia and analgesia, is sufficient to differentiate horses with visceral pain from those believed to be pain-free while using the French-translated Horse Grimace Scale.
• Thus, the scale proves to be a reliable tool to assess pain in horses, regardless of the evaluators’ professional background, thus validating its practical use with flexibility.