Department of Kinesiotherapy and Special Methods in Physiotherapy, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland.
Pain Research Group, Institute of Psychology, Jagiellonian University, Kraków, Poland.
Pain. 2018 Mar;159(3):427-436. doi: 10.1097/j.pain.0000000000001110.
Research shows that chronic pain is related to cortical alterations that can be reflected in reduced tactile acuity, but whether acute pain perception influences tactile acuity has not been tested. Considering the biological role of nociception, it was hypothesized that nociceptive pain will lead to a rapid improvement in tactile acuity and that this effect is correlated with pain intensity and pain distribution. In this randomised double-blind controlled experiment (trial no. NCT03021278), healthy participants were exposed to 1 of 3 experimental conditions: acute, nociceptive low back pain induced by saline injection, a sham injection (without piercing the skin) potentially inducing nocebo pain, or no intervention. Tactile acuity was measured by a battery of tests, including two-point discrimination threshold (TPD), before, during the pain experience, and after it subsided. We found that TPD did not improve but deteriorated during pain induction in the experimental group compared with the control group (P < 0.001; η = 0.20) and changed from 56.94 mm (95% confidence interval: 53.43-60.44) at baseline to 64.22 mm (95% confidence interval: 60.42-68.02) during the pain experience. Maximum reported pain was a significant predictor (β = 0.55, P = 0.01) and accounted for 26% of the variance in TPD (P < 0.05). Other tests, point-to-point test and two-point estimation task, changed with a similar trend but did not reach significance. We concluded that acute, nociceptive pain does not improve but deteriorates tactile acuity linearly. The biological role of the observed phenomenon is unknown, and therefore, future studies should address this question.
研究表明，慢性疼痛与皮质改变有关，这种改变可以反映在触觉敏锐度降低上，但尚未测试急性疼痛感知是否会影响触觉敏锐度。考虑到伤害感受的生物学作用，假设伤害性疼痛会导致触觉敏锐度的快速提高，并且这种效应与疼痛强度和疼痛分布相关。在这项随机、双盲、对照实验（试验编号 NCT03021278）中，健康参与者被暴露于 3 种实验条件之一：急性、伤害性腰痛，由盐水注射引起；假注射（不刺破皮肤），可能引起安慰剂疼痛；或无干预。触觉敏锐度通过一系列测试进行测量，包括两点辨别阈（TPD），在疼痛体验之前、期间和消退后进行。我们发现，与对照组相比，实验组的 TPD 在疼痛诱导期间没有改善反而恶化（P<0.001；η=0.20），从基线时的 56.94mm（95%置信区间：53.43-60.44）变为疼痛体验期间的 64.22mm（95%置信区间：60.42-68.02）。最大报告疼痛是一个显著的预测因素（β=0.55，P=0.01），占 TPD 方差的 26%（P<0.05）。其他测试，点到点测试和两点估计任务，也呈现出相似的趋势，但没有达到显著水平。我们得出结论，急性、伤害性疼痛不会改善，反而会线性地恶化触觉敏锐度。观察到的现象的生物学作用尚不清楚，因此，未来的研究应该解决这个问题。
