Vaguely mediated heart rate variability promotes the perception of paradoxical pain

in Journal of Psychophysiology (2016)

Self-regulation mechanisms are governed by prefrontal inhibitory processes and play a crucial role in the modulation of pain. In the present study the thermal grill paradigm was used to investigate the ... [more ▼]

Self-regulation mechanisms are governed by prefrontal inhibitory processes and play a crucial role in the modulation of pain. In the present study the thermal grill paradigm was used to investigate the association of vagally mediated resting heart rate variability, a psychophysiological marker of trait self-regulatory capacity, with paradoxical pain sensations induced by non-noxious stimulation. This thermal grill illusion is only perceived by part of the tested individuals. The mechanisms underlying the observed inter-individual differences in paradoxical pain sensitivity are largely unknown. During the experimental task, a temperature combination of 15° C and 41° C was set at the glass tubes of the thermal grill. The fifty-two healthy participants placed their dominant hand on the grill for a duration of one minute. The magnitude of sensory and affective pain sensations perceived during stimulation was assessed with numerical rating scales. Before stimulation, a short-term electrocardiogram was recorded to compute vagally mediated heart rate variability at rest. Logistic regression analyses revealed that participants with higher vagal tone were significantly more likely to perceive the thermal grill illusion than subjects displaying lower resting heart rate variability. Paradoxical pain sensations were primarily predicted by normalized respiratory sinus arrhythmia. Our results confirm that the magnitude of vagally mediated resting heart rate variability is associated with the individual disposition to illusive pain perceptions. Since the latter is considered to be a marker of trait self-regulation ability, the present findings may corroborate and complement previous evidence for an impact of psychological characteristics on paradoxical pain sensitivity. [less ▲]

Relationship between cardiovascular reactivity and the perception of the thermal grill illusion of pain

Poster (2015, September 03)

Alterations in blood pressure (BP) and concomitant changes in baroreceptor activation contribute to the modulation of pain sensitivity to warrant homeostatic regulation processes [1][2]. Numerous pain ... [more ▼]

Alterations in blood pressure (BP) and concomitant changes in baroreceptor activation contribute to the modulation of pain sensitivity to warrant homeostatic regulation processes [1][2]. Numerous pain studies have described an inverse relationship between BP and nociceptive sensitivity [3][4][5]. It is not known whether a similar relationship plays a role in the framework of the induction of pain in the absence of noxious stimulation. The thermal grill (TG) paradigm is commonly used to trigger this type of paradoxical pain also termed thermal grill illusion of pain (TGI). The goal of the present study was to explore the relationship between cardiovascular activity/reactivity and paradoxical pain sensitivity to get additional insight in the variability of responsiveness (responders and non-responders) to TG stimulation described in the literature [6][7]. We hypothesized that higher BP would be associated with stronger pain inhibitory effects in participants not perceiving the thermal grill illusion of pain (TGI). We moreover expected that the perception of paradoxical pain in the responder group would be paired with lower BP. We tested this hypothesis by comparing both groups with respect to their spontaneous cardiovascular activity (recorded in resting conditions) and their cardiovascular responses to TG stimulation. [less ▲]

Vagally mediated heart rate variability is a predictor for the occurrence of the thermal grill-induced pain illusion

Poster (2014, October)

Aim: Unpleasantness and negative affect accompany the sensory experience of pain. Both components of pain are heavily influenced by cognitive and emotional processes. In this framework, alterations in ... [more ▼]

Aim: Unpleasantness and negative affect accompany the sensory experience of pain. Both components of pain are heavily influenced by cognitive and emotional processes. In this framework, alterations in baroreceptor reactivity and concomitant changes in cardiac rhythm and blood pressure related to these processes contribute to the modulation of pain sensitivity. Furthermore, self-regulatory capacity has been shown to play a major role in the regulation of cognitive, affective, and behavioural reactions to adverse contexts. These regulatory mechanisms include adjustment of cardiovascular activity and heavily depend on prefrontal cortical processing. Vagally mediated heart rate variability (HRV) at rest is an indicator of the prefrontally modulated vagal activation and has been used as a psychophysiological marker for self-regulatory capacity. The present study investigated the predictive value of the trait self-regulation in the triggering of the thermal grill-induced pain illusion (TGI). We hypothesized inter-individual differences in paradoxical pain perception to be predicted by self-regulatory capacity in a way that participants displaying lower levels of self-regulation should be more likely to perceive the painful grill illusion than subjects with relatively higher self-regulation ability. Methods: A total of 54 healthy participants were recruited among university students and staff. A custom-built, water-bath driven thermal grill device, with interlaced cold and warm glass tubes, was used for the induction of the TGI. A pre-set temperature combination of 15°C and 41°C was applied to the palm of the dominant hand with stimulus durations of 1 min. Subsequent control conditions consisted in the interlaced combination of a baseline temperature of 32°C with one of the stimulus temperatures mentioned above. The procedure was repeated three times. The volunteers used numerical rating scales ranging from 0-100 to rate sensory and affective pain perceptions in intervals of 15 seconds. Vagally mediated HRV at rest was assessed prior to the thermal stimulation protocols. Results: Time-domain components of HRV used as graded indicators of parasympathetic activity and of the extent of self-regulation significantly predicted the possibility of an occurrence of pain and unpleasantness sensations in response to thermal grill stimulation (p <.05). Participants characterized in this way were more likely to express paradoxical pain than subjects not displaying similar levels of HRV. Conclusion: The present results support previous findings indicating an impact of several psychological traits on the individual disposition to paradoxical pain perceptions. Self-regulation ability, operationalized as vagally mediated heart rate variability, can partially explain the probability of perceived pain in response to non-noxious thermal grill stimulation. [less ▲]

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

in BMC Psychology (2014), 2(22),

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 ... [more ▼]

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). [less ▲]

Rumination, interoceptive awareness and suggestibility predict the occurrence of the thermal grill illusion

Poster (2013, October 10)

ruminationInterposed non-noxious cold and warm cutaneous stimuli applied via a thermal grill have repeatedly been shown to generate a paradoxical pain sensation, also described as ‘thermal grill illusion ... [more ▼]

ruminationInterposed non-noxious cold and warm cutaneous stimuli applied via a thermal grill have repeatedly been shown to generate a paradoxical pain sensation, also described as ‘thermal grill illusion of pain’. According to the ‘central disinhibition theory’ proposed by Craig and Bushnell [1], the pain phenomenon commonly qualified as burning can be explained by “an unmasking of cold-evoked activity of polymodal nociceptive lamina I spinothalamic neurons (activation by polymodal Cnociceptors) resulting from the reduction of normal coldevoked activity of thermoreceptive lamina I spinothalamic neurons (activation by Aδ cooling thermoreceptors) by spatial summation of the simultaneous warm stimuli in the thermoreceptive but not the nociceptive neurons.” Since a significant part of the tested subjects do however not display the thermal grill percept, it may be hypothesized that not only physiological-, but also psychological determinants play a crucial role in the generation of the paradoxical pain. Sad mood [2] and anxiety [3] have already been proposed as relevant psychological factors. The aim of the present research consisted in validating our custom made, water-driven and fMRI compatible thermal grill device [4], in identifying thermal grill ‘responders’ and ‘non-responders’ and in investigating whether different personality traits or states constitute predictors for the elicitation of the thermal grill illusion. [less ▲]