The influence of spatial factors on the pain-ameliorating effect of CT-optimal touch

Abstract

Recent studies show that CT-optimal touch, which is the gentle stroking of the skin, may serve as an innovative way to relieve chronic pain. However, there’s still much unknown about the spatial factors influencing its pain-ameliorating effect. This study aims to investigate the effect of CT-optimal touch on pain perception, and whether touch application side matters. To study this, we use Temporal Summation of Second Pain (TSSP), which serves as a model for chronic pain by activating the C-nociceptors. We expect CT-optimal touch to significantly reduce TSSP compared to CT non-optimal touch, and that this effect is irrespective of pain side. 32 participants underwent both touch conditions on both pain sides. To control for possible order effects, we counterbalanced both the touch conditions and the touch application side. The results show that both touch conditions significantly reduced TSSP on the ipsilateral pain side. There was no significant reduction of TSSP on the contralateral pain side. Therefore, we conclude that the pain-ameliorating effect of CT-optimal touch was not irrespective of pain side. Furthermore, CT-optimal touch was not more effective than CT non-optimal touch in reducing pain on the ipsilateral pain side. However, certain limitations in this study, such as a low baseline pain level and possible distraction during the contralateral touch conditions, may have obscured the study results. Therefore, further research with improved methodology is needed to better understand the spatial factors at play, and to clarify the relative efficacy of these touch modalities in chronic pain management.