Aim of Investigation: In healthy people, the effectiveness of analgesia suggestions increases with the individual level of hypnotic susceptibility (HS), a measurable cognitive trait defined as the generalized tendency to respond to hypnotic suggestions. However, chronic pain patients may benefit from analgesia suggestions even when they are low susceptible to hypnosis. Very little is known about the potential brain structural correlates of the responsiveness to analgesia suggestions in chronic pain. Our aim was to assess possible a) psychological and b) gray matter (GM) morphology correlates of inter-individual differences in the patients' behavioural response to an imaginative analgesia suggestion, in women suffering from chronic pain due to fibromyalgia syndrome (FS), using MRI. Methods: Sixty-eight women with FS and 26 healthy women participated in a screening session to fill in questionnaires on depression (CES-D), anxiety (STAI-Y), mental absorption (TAS), imagery ability (BETTS) and (for the patients) on clinical symptoms and pain coping strategies (BPCI). HS was assessed with the Stanford Hypnotic Susceptibility Scale (SHSS:A). A 1.5-min imaginative analgesia suggestion was read once to each patient during normal waking (i.e., without a hypnotic induction) without any prior training. A high-resolution structural T1-weighted brain image (360 sagittal slices without gap; isotropic voxel size 0.5mm; FOV 240 x 240 x 180mm; TR 35ms; flip angle 50°; TE 5.7ms) was acquired for 23 of the patients and all 26 controls, using a 3T Philips Achieva MR scanner. GM volume was assessed applying VBM to modulated data in SPM8, using a tailored DARTEL template for inter-subject alignment. Surface-based measures of cortical thickness and surface area were obtained using the Freesurfer 4.5.0 software. Nuisance influences of age, total intracranial volume, handedness and educational level were removed in the analysis. Results: Patients and controls showed similar HS levels (mean±SD: all patients 4.7±3.0; scanned patients 4.0±3.0; controls: 2.9±2.7). Behavioural data showed that the majority (76%) of patients reported reduction of ongoing pain, either weak-moderate (1-30%; n=20) or strong (>30%; n=32), following the analgesia suggestion reading; a similar proportion was found in patients who underwent scanning. The amount of analgesia was positively correlated with HS (Pearson r=.48), mental absorption (r=.31) and mental avoidance coping (r=.25), and negatively with state anxiety (r=-.41), support-seeking coping (r=-.27) and opioid use; it was independent of all other clinical variables, including pain intensity and duration. While controlling for HS, the amount of analgesia was negatively trend correlated with GM volume in the anterior midbrain/hypothalamus (this cluster missed significance by 11 voxels). In the control sample (but not in the patient sample), higher HS was associated with reduced GM volume in the posterior insula bilaterally. Across the whole scanned group (subjects and patients), HS was associated with reduced cortical thickness in the left medial orbitofrontal cortex. Conclusions: This is the first study to demonstrate a relationship of brain GM anatomical features with HS and the effectiveness of cognitive modulation of clinical pain induced by analgesia suggestions in the waking state. A larger cohort of patients including a higher number of highly hypnotisable individuals is needed to investigate these relationships more thoroughly.
Psychological and brain structural correlates of responsiveness to analgesia suggestions in patients with fibromialgia syndrome / Huber, Alexa; Lui, Fausta; Duzzi, Davide; Summers, Paul Eugene; Carli, G.; Santarcangelo, E. L.; Porro, Carlo Adolfo. - (2012), pp. online-online.
|Data di pubblicazione:||2012|
|Titolo:||Psychological and brain structural correlates of responsiveness to analgesia suggestions in patients with fibromialgia syndrome.|
|Autore/i:||Huber, Alexa; Lui, Fausta; Duzzi, Davide; Summers, Paul Eugene; Carli, G.; Santarcangelo, E. L.; Porro, Carlo Adolfo|
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