Different ways to reach the same goal: Are the analgesic effects of different types of tactile stimuli similar?

Background: Tactile-induced analgesia (TIA) is a phenomenon in which different types of tactile stimulation alleviate pain via different mechanisms including empathy. As TIA plays an essential role in therapeutic situations and clinical conditions, it is crucial to determine whether specific tactile stimulations confer distinct benefits. Methods: Fifty-two subjects (31 females; 21–47 years) were exposed to four distinct experimental conditions involving three types of touch provided within a simulated supportive therapeutic setting. First, a contact heat (70 s) at a pain intensity of 60/100 Numerical Pain Scale (NPS) was applied to the forearm. The pain stimulus was then given simultaneously with vibration, gentle stroking, or handholding in random order. Pain ratings were reported at 5 and 65 s of each stimulation. Given the role of empathy in TIA, we also assessed the levels of empathy experienced by the subjects and the experimenter. Results: Handholding and vibration conditions were associated with a more rapid decrease in pain ratings compared to pain-alone (B values: handholding = −150.94 vs. pain-alone = −99.38, p = 0.01; vibration = −163.54 vs. pain-alone = −99.38, p < 0.001). Higher levels of the experimenter's empathy toward the subjects were associated with greater pain alleviation during vibration vs. pain-alone condition (B values: vibration = −56.42 vs. B pain-alone = −9.57, p = 0.04). Conclusions: Vibration's potent analgesic effects may be attributed to its multi-channel analgesic mechanisms, including the therapist's empathy toward the participant. On the other hand, for handholding establishing an empathic interaction should be considered in a therapeutic setting to enhance its analgesic efficacy. Significance: This article explores the effectiveness of touch-based pain relief methods and their association with empathetic therapeutic interactions. The study emphasizes the significance of positive therapeutic interactions in facilitating tactile-induced analgesia.