De Paepe Annick L, Legrain Valéry, Van der Biest Lien, Hollevoet Nadine, Van Tongel Alexander, De Wilde Lieven, Jacobs Herlinde, Crombez Geert
Department of Experimental-Clinical and Health Psychology, Faculty of Psychology and Educational Sciences, Ghent University, Ghent, Belgium.
Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium.
PeerJ. 2020 Apr 2;8:e8819. doi: 10.7717/peerj.8819. eCollection 2020.
Patients with complex regional pain syndrome (CRPS) report cognitive difficulties, affecting the ability to represent, perceive and use their affected limb. Moseley, Gallace & Spence (2009) observed that CRPS patients tend to bias the perception of tactile stimulation away from the pathological limb. Interestingly, this bias was reversed when CRPS patients were asked to cross their arms, implying that this bias is embedded in a complex representation of the body that takes into account the position of body-parts. Other studies have failed to replicate this finding (Filbrich et al., 2017) or have even found a bias in the opposite direction (Sumitani et al., 2007). Moreover, perceptual biases in CRPS patients have not often been compared to these of other chronic pain patients. Chronic pain patients are often characterized by an excessive focus of attention for bodily sensations. We might therefore expect that non-CRPS pain patients would show a bias towards instead of away from their affected limb. The aim of this study was to replicate the study of Moseley, Gallace & Spence (2009) and to extend it by comparing perceptual biases in a CRPS group with two non-CRPS pain control groups (i.e., chronic unilateral wrist and shoulder pain patients). In a temporal order judgment (TOJ) task, participants reported which of two tactile stimuli, one applied to either hand at various intervals, was perceived as occurring first. TOJs were made, either with the arms in a normal (uncrossed) position, or with the arms crossed over the body midline. We found no consistent perceptual biases in either of the patient groups and in either of the conditions (crossed/uncrossed). Individual differences were large and might, at least partly, be explained by other variables, such as pain duration and temperature differences between the pathological and non-pathological hand. Additional studies need to take these variables into account by, for example, comparing biases in CRPS (and non-CRPS) patients in an acute versus a chronic pain state.
复杂性区域疼痛综合征（CRPS）患者报告存在认知困难，这影响了他们对患侧肢体的表征、感知和使用能力。莫斯利、加拉塞和斯彭斯（2009年）观察到，CRPS患者倾向于将触觉刺激的感知偏向远离患病肢体的方向。有趣的是，当要求CRPS患者交叉双臂时，这种偏向会反转，这意味着这种偏向嵌入在一个考虑身体各部分位置的复杂身体表征中。其他研究未能重复这一发现（菲尔布里希等人，2017年），甚至发现了相反方向的偏向（苏米塔尼等人，2007年）。此外，CRPS患者的感知偏向很少与其他慢性疼痛患者的感知偏向进行比较。慢性疼痛患者的特点通常是对身体感觉过度关注。因此，我们可能会预期非CRPS疼痛患者会表现出朝向而不是远离患侧肢体的偏向。本研究的目的是重复莫斯利、加拉塞和斯彭斯（2009年）的研究，并通过将CRPS组与两个非CRPS疼痛对照组（即慢性单侧手腕和肩部疼痛患者）的感知偏向进行比较来扩展该研究。在时间顺序判断（TOJ）任务中，参与者报告两个触觉刺激中哪一个（以不同间隔分别施加于两只手）被感知为先出现。TOJ判断是在双臂处于正常（未交叉）位置或双臂交叉于身体中线的情况下进行的。我们在任何一个患者组以及任何一种条件（交叉/未交叉）下都未发现一致的感知偏向。个体差异很大，并且至少部分可以由其他变量解释，例如疼痛持续时间以及患病手和未患病手之间的温度差异。未来的研究需要考虑这些变量，例如，比较CRPS（和非CRPS）患者在急性疼痛状态与慢性疼痛状态下的偏向。
