Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Neuroscience Center Zurich, University of Zurich, Zurich, Switzerland.
Spinal Cord Injury Center, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
Clin Neurophysiol. 2024 Oct;166:31-42. doi: 10.1016/j.clinph.2024.07.007. Epub 2024 Jul 20.
The present study aimed to investigate whether subjective and objective measures of pain habituation can be used as potential markers for central sensitization across various chronic pain patients.
Two blocks of contact-heat stimuli were applied to a non-painful area in 93 chronic pain patients (low back pain, neuropathic pain, and complex regional pain syndrome) and 60 healthy controls (HC). Habituation of pain ratings, contact-heat evoked potentials (CHEP), and sympathetic skin responses (SSR) was measured.
There was no significant difference in any measure of pain habituation between patients and HC. Even patients with apparent clinical signs of central sensitization showed no reduced pain habituation. However, prolonged baseline CHEP and SSR latencies (stimulation block 1) were found in patients compared to HC (CHEP: Δ-latency = 23 ms, p = 0.012; SSR: Δ-latency = 100 ms, p = 0.022).
Given the performed multimodal neurophysiological testing protocol, we provide evidence indicating that pain habituation may be preserved in patients with chronic pain and thereby be of limited use as a sensitive marker for central sensitization. These results are discussed within the framework of the complex interactions between pro- and antinociceptive mechanism as well as methodological issues. The prolonged latencies of CHEP and SSR after stimulation in non-painful areas may indicate subclinical changes in the integrity of thermo-nociceptive afferents, or a shift towards antinociceptive activity. This shift could potentially affect the relay of ascending signals.
Our findings challenge the prevailing views in the literature and may encourage further investigations into the peripheral and central components of pain habituation, using advanced multimodal neurophysiological techniques.
本研究旨在探讨主观和客观的疼痛习惯化测量是否可以作为各种慢性疼痛患者的中枢敏感化的潜在标志物。
在 93 名慢性疼痛患者（腰痛、神经病理性疼痛和复杂性区域疼痛综合征）和 60 名健康对照者（HC）的非疼痛区域施加两区块的接触热刺激。测量疼痛评分、接触热诱发电位（CHEP）和交感皮肤反应（SSR）的习惯化。
患者与 HC 之间在任何疼痛习惯化测量上均无显著差异。即使有明显的中枢敏感化临床迹象的患者也没有表现出疼痛习惯化的降低。然而，与 HC 相比，患者的基线 CHEP 和 SSR 潜伏期（刺激块 1）延长（CHEP：Δ潜伏期=23ms，p=0.012；SSR：Δ潜伏期=100ms，p=0.022）。
鉴于所进行的多模态神经生理学测试方案，我们提供的证据表明，慢性疼痛患者的疼痛习惯化可能得到保留，因此作为中枢敏感化的敏感标志物的作用有限。这些结果在促和抗伤害性机制的复杂相互作用以及方法学问题的框架内进行了讨论。非疼痛区域刺激后 CHEP 和 SSR 的潜伏期延长可能表明热敏传入纤维的亚临床完整性改变，或向抗伤害性活动的转变。这种转变可能会影响上行信号的传递。
我们的发现挑战了文献中的主流观点，并可能鼓励使用先进的多模态神经生理学技术进一步研究疼痛习惯化的外周和中枢成分。
