OBJECTIVE To study lateral inhibition and habituation/sensitization in the somatosensory cortex of patients with chronic migraine (CM) and to identify correlations with clinical migraine features. METHODS Sixteen patients with CM without medication overuse, and 17 healthy volunteers (HVs) received somatosensory evoked potentials (SSEPs) elicited by separate electrical stimulation of the right median (M) and ulnar (U) nerves at the wrist and by simultaneous nerve stimulation (MU). We measured the N20-P25 amplitudes and calculated the lateral inhibition (LI) percentage using the formula {100-[MU/(M + U) * 100]}. We also calculated sensitization (SSEP amplitude during block 1) and delayed habituation to M-nerve stimulation. RESULTS The percentage of LI did not differ between the groups (40.2% in HV, 47.4% in CM, p = 0.276) and was negatively correlated with the monthly headache-day number (r = -0.532, p = 0.034). Patients showed a generalized increase in SSEP amplitudes compared to HVs and habituated normally. CONCLUSIONS We showed a pattern of somatosensory response in CM similar to that observed during attacks of episodic migraine. SIGNIFICANCE In the transition process between episodic migraine and CM, LI attempts to physiologically counteract the mounting increase in attack frequency, but this is insufficient to allow patients to exit the chronic phase.

中文翻译：

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慢性偏头痛患者躯体感觉皮层侧向抑制机制的功能正常

目的 研究慢性偏头痛 (CM) 患者躯体感觉皮层的侧向抑制和习惯/敏化，并确定与临床偏头痛特征的相关性。方法 16 名未过度用药的 CM 患者和 17 名健康志愿者 (HVs) 接受了由腕部右侧正中 (M) 和尺骨 (U) 神经的单独电刺激和同时神经刺激引起的体感诱发电位 (SSEP)。亩）。我们测量了 N20-P25 振幅并使用公式 {100-[MU/(M + U) * 100]} 计算了侧抑制 (LI) 百分比。我们还计算了敏化（第 1 组期间的 SSEP 振幅）和延迟对 M 神经刺激的习惯。结果 LI 的百分比在各组之间没有差异（HV 40.2%，CM 47.4%，p = 0。276）并且与每月头痛天数呈负相关（r = -0.532，p = 0.034）。与 HV 相比，患者表现出 SSEP 振幅的普遍增加，并且习惯了正常。结论 我们在 CM 中显示了一种类似于发作性偏头痛发作期间观察到的体感反应模式。意义 在发作性偏头痛和 CM 之间的过渡过程中，LI 试图在生理上抵消发作频率的不断增加，但这不足以让患者退出慢性期。