Neurophysiopathology of Pain Unit, Neuroscience and Sensory Systems Department, University of Bari Aldo Moro, Bari, Italy.
CNS Neurol Disord Drug Targets. 2012 Mar;11(2):110-26. doi: 10.2174/187152712800269759.
Belief and expectation are part of placebo effect. Migraine patients are characterized by a dysfunctional modulation of pain processing, though a clear placebo effect emerges in clinical trials. The aim of the study was to evaluate the effect of visual and verbal suggestion on subjective pain sensation and cortical responses evoked by CO2 painful laser stimuli in migraine without aura patients vs healthy controls. Twenty-six patients were recorded during the inter-ictal phase and compared to 26 sex and age-matched controls. The right hand and the right supraorbital zone were stimulated during a not conditioned and a conditioned task, where laser stimuli were delivered after a verbal and visual cues of decreased (D), increased (I) or basal (B) intensity, which was left unmodified during the entire task. In control subjects pain rating changed, according to the announced intensity, while in migraine patients the basal hyper-algesia remained unmodified. The N1 and N2 amplitudes tended to change coherently with the stimulus cue in controls, while an opposite paradoxical increase in decreasing condition emerged in migraine. The P2 amplitude modulation was also reduced in migraine, differently from controls. The altered pattern of pain rating and N2 amplitude modulation concurred with frequency of migraine, disability and allodynia. In controls suggestion influenced cortical pain processing and subjective pain rating, while in migraine a peculiar pattern of cortical activation contrasted external cues in order to maintain the basal hyper-algesia. This scarce influence of induced suggestion on pain experience seemed to characterize patients with more severe migraine and central sensitization.
信念和期望是安慰剂效应的一部分。偏头痛患者的疼痛处理存在功能障碍，尽管在临床试验中出现了明显的安慰剂效应。本研究旨在评估视觉和语言暗示对无先兆偏头痛患者和健康对照者 CO2 疼痛激光刺激引起的主观疼痛感觉和皮质反应的影响。在发作间期记录了 26 例患者，并与 26 例性别和年龄匹配的对照者进行了比较。在非条件和条件任务中刺激右手和右眶上区，在条件任务中，激光刺激在强度降低（D）、增加（I）或基础（B）的口头和视觉提示后发出，在整个任务中保持不变。在对照者中，疼痛评分根据宣布的强度发生变化，而在偏头痛患者中，基础痛觉过敏保持不变。N1 和 N2 振幅倾向于与控制者的刺激线索一致变化，而在偏头痛患者中，在降低条件下出现相反的矛盾增加。偏头痛患者的 P2 振幅调制也减少，与对照者不同。疼痛评分和 N2 振幅调制的改变模式与偏头痛的频率、残疾和痛觉过敏相一致。在对照者中，暗示影响皮质疼痛处理和主观疼痛评分，而在偏头痛患者中，皮质激活的特殊模式与外部线索相反，以维持基础痛觉过敏。这种诱导暗示对疼痛体验的影响似乎是偏头痛和中枢敏化更严重的患者的特征。
