Asymmetry in Pain Perception between the Right and Left Hands to Experimentally Induced Pain Stimuli: A Randomized Study

This single-blind, randomized controlled trial examined pain sensitivity discrepancies between dominant and non-dominant hands among 15 right-handed adults. Participants underwent electrically induced pain, heat pain, and cold pain stimuli. This study examined pain intensity (VAS), emotional sweating, heat pain threshold, the Profile of Mood State (POMS), and salivary chromogranin A (CgA) in the participants. The results indicated a significantly higher intensity of electrically induced pain in the left hand than in the right hand. However, heat and cold pain intensities and heat pain thresholds exhibited no significant differences between the hands. Emotional sweating was consistent across both hands and all pain stimuli. Salivary CgA levels remained unchanged across pain conditions. Further, the POMS data indicated that only vigor subscale scores for all pain stimuli significantly differed from those of the pre-condition. Therefore, the findings suggest that the non-dominant left hand is more sensitive to electrically induced pain in right-handed individuals.