Medical Section, Department of Orthopaedic and Trauma Surgery, Academic Physiotherapy, Pain and Exercise Research Luebeck (P.E.R.L), University of Luebeck, Luebeck, Germany.
Department of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
Pain. 2020 Mar;161(3):557-564. doi: 10.1097/j.pain.0000000000001739.
The complex mechanisms underlying migraine are not entirely understood. It has been suggested that descending endogenous pain modulation is an important contributing factor, although research is controversial. A frequently used method to quantify the inhibitory pain modulation system is offset analgesia (OA), defined as a disproportionally large decrease in pain perception in response to a small decrease of painful stimulation. The aim of this study is to evaluate the OA response in patients with migraine and healthy controls, measured at the forehead (trigeminal, V1) and forearm (extratrigeminal). Patients with episodic migraine during the headache-free interval (n = 26) and age- and sex-matched headache-free controls (n = 26) were included in this cross-sectional study. All participants underwent an individualized OA paradigm consisting of 3 stimulus offset trials and 3 constant temperature trials examined at both, a trigeminal and an extratrigeminal test site. Items from the quantitative sensory testing protocol were additionally included. In contrast to the extratrigeminal area, a reduced OA response was shown in the trigeminal area in patients with migraine compared with healthy controls (P < 0.01, mean difference: 13.7, 95% confidence interval: 3.8-23.6). Statistically significant differences between the trigeminal area and the extratrigeminal area were neither observed in healthy controls nor in patients with migraine (P > 0.05). Mechanical detection, mechanical pain threshold, warm detection, and heat pain threshold showed no significant differences between groups or test sites (P > 0.05). In summary, patients with episodic migraine in the headache-free interval exhibited somatotopically specific differences in endogenous pain modulation.
偏头痛的发病机制十分复杂，目前尚未完全阐明。有研究认为，下行内源性疼痛调制是一个重要的影响因素，但该研究结果存在争议。目前，常用来量化内源性抑制性疼痛调制系统的方法是刺激偏移量镇痛（OA），定义为在小的疼痛刺激减少时，出现不成比例的疼痛感知下降。本研究旨在评估偏头痛患者和健康对照者额部（三叉神经，V1）和前臂（三叉神经外）的 OA 反应。本横断面研究纳入了头痛间歇期的偏头痛患者（n=26）和年龄、性别匹配的无头痛健康对照者（n=26）。所有参与者均接受了个体化的 OA 范式，包括 3 次刺激偏移试验和 3 次恒定温度试验，分别在三叉神经和三叉神经外测试部位进行。此外，还包括定量感觉测试方案中的项目。与三叉神经外区域相比，偏头痛患者的三叉神经区域的 OA 反应明显降低（P<0.01，平均差异：13.7，95%置信区间：3.8-23.6）。健康对照者和偏头痛患者的三叉神经区域和三叉神经外区域之间均未观察到统计学差异（P>0.05）。在组间或测试部位之间，机械检测、机械疼痛阈值、热觉检测和热痛阈值均无显著差异（P>0.05）。总之，头痛间歇期的偏头痛患者表现出特定躯体部位的内源性疼痛调制差异。
