Rumination and interoceptive accuracy predict the occurrence of the thermal grill illusion of pain

Background: While the physiological mechanisms of the thermal grill illusion of pain (TGI) are largely understood, psychological determinants remain mainly unknown. The present study aimed to investigate whether cognitive and affective personality traits encompassing rumination, interoception and suggestibility contribute to the inducibility of paradoxical pain.
Methods: The dominant hand of 54 healthy volunteers was stimulated with a water-bath driven thermal grill providing an interlaced temperature combination of 15 and 41°C. Pain intensity and pain unpleasantness perceptions were rated on a numerical scale (NRS). Traits were assessed via questionnaires, the heartbeat-tracking task, and warmth suggestions.
Results: Logistic regression analyses uncovered trait rumination and interoceptive accuracy (IA) as major predictors of the likelihood of the illusive pain occurrence (all p < .05). Rumination and suggestibility had an impact on unpleasant pain perceptions.
Conclusion: Our findings demonstrate a significant influence of psychological aspects on the individual disposition to the painful grill illusion (PGI).