Postural effects of imagined leg pain as a function of hypnotizability

Department of Physiological Sciences, University of Pisa, Via San Zeno 31, 56127 Pisa, Italy.
Experimental Brain Research (Impact Factor: 2.04). 11/2011; 216(3):341-8. DOI: 10.1007/s00221-011-2935-1
Source: PubMed


It has been shown that, in subjects with high hypnotizability (Highs), imagined somatosensory stimulation can involuntarily activate the neural circuits involved in the modulation of reflex action. In this vein, aim of the study was to investigate whether the imagery of nociceptive stimulation in one leg may produce both subjective experience of pain and congruent postural adjustments during normal upright stance. The displacement of the centre of pressure (CoP) was studied during imagery of leg pain (LP) and during the control conditions of imagery of tactile stimulation of the same leg and of throat pain (TP) in 12 Highs and 12 low hypnotizable subjects (Lows). The results showed that the vividness of imagery was higher in Highs than in Lows for all tasks and that only Highs reported actually feeling pain during LP and TP. Congruently, during LP only Highs displaced their CoP towards the leg opposite to the one that was the object of painful imagery and increased their CoP mean velocity and area of excursion. Since the Highs' postural changes were not accounted for only by vividness of imagery and perceived pain intensity, high hypnotizability is apparently responsible for part of the postural effects of pain imagery.

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Available from: Enrica Santarcangelo, May 19, 2014
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    • "Indeed, I have found hypnotizability-related differences (Carli et al., 2006, 2008; Santarcangelo et al., 2008, 2010; Menzocchi et al., 2010, 2012; Castellani et al., 2011; Scattina et al., 2012) in many aspects of sensorimotor integration in both the absence (Table 1) (Collins and De Luca, 1993; Caratelli et al., 2010; Mecacci et al., 2013) and the presence of suggestions. I have chosen the differences in postural control induced by imagined sensory alteration (Carli et al., 2006; Santarcangelo et al., 2010; Scattina et al., 2012) as the object of this article. I will also show that my physiological approach to the field of hypnotizability allows to suggest that the involuntariness reported by highs in their response to sensory suggestions is physiologically sustained and, thus, " real " rather than only subjectively experienced (Santarcangelo et al., 2010). "

    Full-text · Article · Jun 2014 · Frontiers in Behavioral Neuroscience
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    • "Imagery can interact with sensory information, as shown by the observation that a bilateral plantar flexion imagery task has been found associated with postural parameters predicting blindness onset in both early and late blind subjects (Rodrigues et al., 2003). Moreover, kinesthetic motor imagery modulates body sway (Rodrigues et al., 2010), the mental image of jumping decreases the pressure on a stabilometric platform (Grangeon, Guillot, & Collet, 2011; Olsson, Jonsson, Larsson, & Nyberg, 2008), imagery of a one-legged stance displaces the CoP toward the supporting leg (Mecacci, Menzocchi, Zeppi, Carli, & Santarcangelo, 2013), and effective imagery of pain in one leg displaces the CoP toward the nonpainful leg similarly to what occurs after the corresponding physical injury (Scattina et al., 2012). "
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    ABSTRACT: Abstract In the general population, suppression of vision modulates body sway by increasing the center of pressure (CoP) velocity, while a light fingertip touch reduces the area of the CoP displacement in blindfolded subjects. This study assessed whether imagined fixation and fingertip touch differentially stabilize posture in subjects with high (highs) and low (lows) hypnotizability. Visual and tactile imageries were ineffective in lows. In highs, the effects of visual imagery could not be evaluated because the real information was ineffective; real tactile stimulation was effective only on velocity, but the imagery effects could not be definitely assessed owing to low effect size. The highs' larger variability could account for this and represents the most important finding.
    Full-text · Article · May 2014 · International Journal of Clinical and Experimental Hypnosis
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    • "The absence of cpt induced respiratory modulation is in line with other reports [12], [13], the lower skin blood flow observed in highs with respect to lows throughout the experimental session may be a consequence of the highs’ greater absorption (TAS scores) and/or imagery abilities [8], [44] likely able to induce pain and peripheral vasoconstriction through imagery of the expected cold pressor test. Finally, the lower blood pressure observed in females with respect to males is in line with the current literature on gender related control of blood pressure [43] and the increased skin conductance in the non immersed hand of both groups should be interpreted as a general stress response [45]. "
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    ABSTRACT: In healthy subjects with high hypnotisability (highs) under hypnosis, subjectively effective suggestions for analgesia abolish the increases in blood pressure associated with cold pressor test (cpt) by reducing the peripheral vascular resistance. The aim of the present study was to investigate the effects of the suggestions of analgesia on the responses to cpt in healthy highs (n = 22) and in low hypnotisable participants (lows, n = 22) out of hypnosis. Cpt was administered without (CPT) and with suggestions for analgesia (CPT+AN). Psychophysical (pain intensity, pain threshold, cpt duration (time of immersion) and pain tolerance, defined as the difference between cpt duration and pain threshold), respiratory (amplitude and frequency) and autonomic variables (tonic skin conductance, mean RR interval (RR = 1/heart rate), blood pressure, skin blood flow) were studied. The suggestions for analgesia increased cpt duration and RR in both groups, but decreased pain intensity and enhanced pain threshold only in highs; in both groups they did not modulate systolic blood pressure, tonic skin conductance and skin blood flow; thus, increased parasympathetic activity appears responsible for the heart rate reduction induced by suggestions in both groups. In conclusion, our findings show that suggestions modulate pain experience differentially in highs and lows, and are partially effective also in lows. We hypothesize that the mechanisms responsible for the efficacy of suggestions in healthy lows may be involved also in their efficacy in chronic pain patients with low hypnotisability.
    Full-text · Article · Oct 2013 · PLoS ONE
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