Pilot study evaluating surface temperature in dogs with or without fear-based aggression

Abstract

Abstract The use of a standardized physiological measure in veterinary behavior evaluations would improve both accuracy of the diagnosis and monitoring of the treatment response. Infrared thermography (IRT) is a noninvasive, remote assessment tool used primarily in research to evaluate changes in surface body temperature resulting from underlying physiological processes. IRT has not been examined widely in a veterinary behavior clinic setting, and its clinical validity requires testing. In this pilot study, patient data were reviewed retrospectively from a veterinary teaching hospital's behavior clinic population to determine if surface eye temperature as measured by IRT differed in dogs with fear-based aggression compared to dogs with various other behavioral diagnoses. Forty-six dogs were subdivided into groups with fear-based aggression toward unfamiliar people (n = 32) or no fear-based aggression but with other behavioral diagnoses (n = 14) to compare surface eye temperature and behavioral responses in the clinic setting. The potentially provocative stimulus was the presence of unfamiliar people in the consultation room (clinician and student). The primary outcomes of interest were change in surface eye temperature and behavioral responses between 2 time points 45 minutes apart during the 60-minute consultation. It was hypothesized that in contrast to dogs with fear-based aggression, IRT-measured mean surface eye temperature in dogs without fear-based aggression would decrease between the 2 time points. Instead, surface eye temperature increased in both groups of dogs without significant difference between the groups (P = 0.16). Dog's posture and proximity to the owner in the consultation room at the start of the evaluation also were not significantly different between the 2 groups. However, 27% of the fear-based aggressive dogs compared with 0% of the dogs with other diagnoses exhibited aggressive reactions to unfamiliar people who stood up to leave the consultation room at the end of the visit. Study design factors likely contributed to the negative findings. First, the study population was derived from clinic behavior patients, and dogs in both groups had multiple behavioral diagnoses that may have impacted their response to stress in the clinic setting. In addition, all dogs were tethered during the consultation visit, and this may have triggered underlying anxiety in both groups of dogs. A future study that addresses these study design factors would be needed to determine whether IRT-measured surface eye temperature in a clinical setting is a helpful measure.