Effects of Neck and Back Touch on Ultrasonic Vocalization and the Rat Grimace Scale in Rats Receiving Intramuscular Injections

ABSTRACT

PURPOSE: To determine the effects of neck and back touch on Ultrasonic Vocalization (UV) and the Rat Grimace Scale (RGS) in rats touched by the human hand as an intervention for reducing pain and anxiety associated with intramuscular injections. METHODS: This study was a randomized, controlled, pre-test/post-test design study. Twenty male Sprague-Dawley rats were assigned to either the experimental or control groups (n=10 rats/group). The experimental group was touched in a manner similar to massaging the rat's neck and back twice a day for one week. The two groups received two intramuscular injections. The 22kHz and 50kHz UV and the RGS scores were measured before and after each intramuscular injection. RESULTS: The 22kHz UV and RGS score were significantly higher in the control group than in the experimental group when the first intramuscular injection was administered; whereas, no difference between the experimental and the control groups were observed when the second intramuscular injection was administered. There was no statistical difference in the 50kHz UV between the two groups when the first and second injections were administered. CONCLUSION: This study found that touching was an effective intervention method to reduce negative emotions and pain in rats receiving their first intramuscular injection.