Learning mechanisms in nocebo hyperalgesia: the role of conditioning and extinction processes

Abstract

Learning mechanisms in nocebo hyperalgesia: The role of conditioning and extinction processes. Thomaidou et al. Appendix 1. The TENS handout (translated from Dutch)Effectivity of electrical nerve stimulation (ENS) in increasing pain.Electrical nerve stimulation (ENS) is the administration of an electrical current produced by a

An experimental investigation into the mediating role of pain-related fear in boosting nocebo hyperalgesia

“…In the acquisition phase, the activation of sham electrical stimulation was repeatedly paired with increased pain stimulation during the 12 nocebo trials, whereas the 12 control trials were paired with lower pain stimulation. This is in line with previous nocebo studies 19 , 68 implementing classical conditioning for the experimental induction of nocebo hyperalgesia. In the extinction phase, both nocebo and control cues were paired with the same lower intensity pain stimulation.…”

“…The required sample size for the primary analysis was calculated based on our previous nocebo study 68 comparing the magnitude of nocebo responses between 3 groups that received different conditioning manipulations. The analysis was conducted in G*power 3.1 28 for a mixed-model analysis of variance (ANOVA).…”

“…Pain calibrations were conducted to select the temperatures that would be used to induce low, moderate, and high pain in the acquisition and extinction phases (similar to previous studies 39 , 68 ). The calibrations were individually tailored, based on participants' NRS ratings of maximum 30 pain stimuli of varying intensities, ranging from 41 to 49.9°C.…”

“…Negative expectations regarding an inert treatment stimulus have been shown to increase perceived pain intensity, as compared to perceived pain intensity in an untreated, control condition. 3 , 27 , 59 , 63 , 68 This phenomenon has been termed nocebo hyperalgesia. 3 , 9 In experimental studies, negative suggestions and classical conditioning play key roles in the acquisition of nocebo hyperalgesia.…”

“… 29 , 62 , 63 Studies have used varying pain levels to induce nocebo hyperalgesia, ranging from as low as 5 to as high as 10 on 0 (no pain) to 10 (highest pain imaginable) rating scales. 8 , 31 , 36 , 68 , 69 These pain intensities may differentially induce fear and, as such, influence nocebo responses. Furthermore, the threatening nature of suggestions also varies between experimental nocebo models.…”