de Tommaso Marina, Lo Sito Luciana, Di Fruscolo Olimpia, Sardaro Michele, Pia Prudenzano Maria, Lamberti Paolo, Livrea Paolo
Neurologic and Psychiatric Sciences Department, Bari University, Clinica Neurologica, Policlinico, Piazza Giulio Cesare 11, 70124 Bari.
Clin Neurophysiol. 2005 Jun;116(6):1254-64. doi: 10.1016/j.clinph.2005.02.018. Epub 2005 Apr 2.
The aim of the present study was to investigate the habituation of subjective pain sensation to CO(2) laser stimulus, in relation to the amplitude modifications of the cortical evoked responses (LEPs), during both the migraine attack and the not symptomatic phase.
Fourteen migraine patients were selected and compared with 10 healthy controls. Eight patients were evaluated during both the pain-free and the attack phases. Three following series of 20 averaged LEPs were recorded, stimulating the hands and the supraorbital zones: during the attack, two consecutive series of 20 averaged LEPs were carried out. The subjective sensation was requested for each laser stimulus, using a 0-10 points Verbal Rating Scale (VRS).
In normal subjects the N2-P2 waves amplitude showed habituation across the three repetitions, which correlated with the habituation of the subjective rating of the stimulus. During the not symptomatic phase, patients showed a lack of habituation of the N2-P2 amplitude when the hand and the face was stimulated, with a pattern of increase of the pain rating across the three repetitions; in addition there was a lack of correlation between the LEPs amplitude and the subjective sensation. During the attack, the LEPs amplitude and the pain rating were increased when the face was stimulated, but they did not habituate across the two repetitions, likely the pain-free condition. The percent LEPs amplitude variation across the three repetitions correlated with the main indices of migraine severity, mainly when the supraorbital zone was stimulated.
The abnormal cortical excitability in migraine could condition an anomalous behavior of nociceptive cortex during the interictal phase of migraine: it persists during the acute phase, and correlates with the frequency and duration of migraine.
The reduced habituation of the nociceptive cortex may concur with the onset and evolution of headache.
本研究旨在探讨偏头痛发作期和无症状期主观疼痛感觉对二氧化碳激光刺激的适应性，以及与皮质诱发电位（LEPs）振幅变化的关系。
选取14例偏头痛患者，并与10名健康对照者进行比较。8例患者在无痛期和发作期均接受评估。在刺激手部和眶上区域时，记录三组连续的20次平均LEPs：发作期进行两组连续的20次平均LEPs记录。使用0 - 10分的视觉模拟评分法（VRS）对每次激光刺激的主观感觉进行评估。
在正常受试者中，N2 - P2波振幅在三次重复刺激过程中呈现适应性变化，这与刺激主观评分的适应性相关。在无症状期，刺激手部和面部时，患者的N2 - P2振幅缺乏适应性，疼痛评分在三次重复刺激过程中呈增加趋势；此外，LEPs振幅与主观感觉之间缺乏相关性。在发作期，刺激面部时LEPs振幅和疼痛评分增加，但在两次重复刺激过程中未出现适应性，可能与无痛状态有关。三次重复刺激过程中LEPs振幅变化百分比与偏头痛严重程度的主要指标相关，主要是在刺激眶上区域时。
偏头痛患者皮质兴奋性异常可能导致偏头痛发作间期伤害性感受皮质的异常行为：在急性期持续存在，并与偏头痛的频率和持续时间相关。
伤害性感受皮质适应性降低可能与头痛的发作和演变有关。
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