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Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses
During the last decade, a number of pain assessment tools based on facial expressions have been developed for horses. While all tools focus on moveable facial muscles related to the ears, eyes, nostrils, lips, and chin, results are difficult to compare due to differences in the research conditions,...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608869/ https://www.ncbi.nlm.nih.gov/pubmed/33141852 http://dx.doi.org/10.1371/journal.pone.0231608 |
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author | Rashid, Maheen Silventoinen, Alina Gleerup, Karina Bech Andersen, Pia Haubro |
author_facet | Rashid, Maheen Silventoinen, Alina Gleerup, Karina Bech Andersen, Pia Haubro |
author_sort | Rashid, Maheen |
collection | PubMed |
description | During the last decade, a number of pain assessment tools based on facial expressions have been developed for horses. While all tools focus on moveable facial muscles related to the ears, eyes, nostrils, lips, and chin, results are difficult to compare due to differences in the research conditions, descriptions and methodologies. We used a Facial Action Coding System (FACS) modified for horses (EquiFACS) to code and analyse video recordings of acute short-term experimental pain (n = 6) and clinical cases expected to be in pain or without pain (n = 21). Statistical methods for analyses were a frequency based method adapted from human FACS approaches, and a novel method based on co-occurrence of facial actions in time slots of varying lengths. We describe for the first time changes in facial expressions using EquiFACS in video of horses with pain. The ear rotator (EAD104), nostril dilation (AD38) and lower face behaviours, particularly chin raiser (AU17), were found to be important pain indicators. The inner brow raiser (AU101) and eye white increase (AD1) had less consistent results across experimental and clinical data. Frequency statistics identified AUs, EADs and ADs that corresponded well to anatomical regions and facial expressions identified by previous horse pain research. The co-occurrence based method additionally identified lower face behaviors that were pain specific, but not frequent, and showed better generalization between experimental and clinical data. In particular, chewing (AD81) was found to be indicative of pain. Lastly, we identified increased frequency of half blink (AU47) as a new indicator of pain in the horses of this study. |
format | Online Article Text |
id | pubmed-7608869 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-76088692020-11-10 Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses Rashid, Maheen Silventoinen, Alina Gleerup, Karina Bech Andersen, Pia Haubro PLoS One Research Article During the last decade, a number of pain assessment tools based on facial expressions have been developed for horses. While all tools focus on moveable facial muscles related to the ears, eyes, nostrils, lips, and chin, results are difficult to compare due to differences in the research conditions, descriptions and methodologies. We used a Facial Action Coding System (FACS) modified for horses (EquiFACS) to code and analyse video recordings of acute short-term experimental pain (n = 6) and clinical cases expected to be in pain or without pain (n = 21). Statistical methods for analyses were a frequency based method adapted from human FACS approaches, and a novel method based on co-occurrence of facial actions in time slots of varying lengths. We describe for the first time changes in facial expressions using EquiFACS in video of horses with pain. The ear rotator (EAD104), nostril dilation (AD38) and lower face behaviours, particularly chin raiser (AU17), were found to be important pain indicators. The inner brow raiser (AU101) and eye white increase (AD1) had less consistent results across experimental and clinical data. Frequency statistics identified AUs, EADs and ADs that corresponded well to anatomical regions and facial expressions identified by previous horse pain research. The co-occurrence based method additionally identified lower face behaviors that were pain specific, but not frequent, and showed better generalization between experimental and clinical data. In particular, chewing (AD81) was found to be indicative of pain. Lastly, we identified increased frequency of half blink (AU47) as a new indicator of pain in the horses of this study. Public Library of Science 2020-11-03 /pmc/articles/PMC7608869/ /pubmed/33141852 http://dx.doi.org/10.1371/journal.pone.0231608 Text en © 2020 Rashid et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Rashid, Maheen Silventoinen, Alina Gleerup, Karina Bech Andersen, Pia Haubro Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title | Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title_full | Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title_fullStr | Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title_full_unstemmed | Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title_short | Equine Facial Action Coding System for determination of pain-related facial responses in videos of horses |
title_sort | equine facial action coding system for determination of pain-related facial responses in videos of horses |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608869/ https://www.ncbi.nlm.nih.gov/pubmed/33141852 http://dx.doi.org/10.1371/journal.pone.0231608 |
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