Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.
University Hospital Saint-Luc, Brussels, Belgium.
Sci Rep. 2017 Aug 29;7(1):9712. doi: 10.1038/s41598-017-10077-8.
Complex regional pain syndrome (CRPS) is a chronic pain condition associating sensory, motor, trophic and autonomic symptoms in one limb. Cognitive difficulties have also been reported, affecting the patients' ability to mentally represent, perceive and use their affected limb. However, the nature of these deficits is still a matter of debate. Recent studies suggest that cognitive deficits are limited to body-related information and body perception, while not extending to external space. Here we challenge that statement, by using temporal order judgment (TOJ) tasks with tactile (i.e. body) or visual (i.e. extra-body) stimuli in patients with upper-limb CRPS. TOJ tasks allow characterizing cognitive biases to the advantage of one of the two sides of space. While the tactile TOJ tasks did not show any significant results, significant cognitive biases were observed in the visual TOJ tasks, affecting mostly the perception of visual stimuli occurring in the immediate vicinity of the affected limb. Our results clearly demonstrate the presence of visuospatial deficits in CRPS, corroborating the cortical contribution to the CRPS pathophysiology, and supporting the utility of developing rehabilitation techniques modifying visuospatial abilities to treat chronic pain.
复杂性区域疼痛综合征 (CRPS) 是一种慢性疼痛病症，会导致单侧肢体出现感觉、运动、营养和自主神经症状。有研究报道称，CRPS 患者还存在认知障碍，影响其对患病肢体的心理表象、感知和使用能力。然而，这些缺陷的性质仍存在争议。最近的研究表明，认知缺陷仅限于与身体相关的信息和身体感知，而不会扩展到外部空间。在这里，我们通过使用时间顺序判断 (TOJ) 任务来挑战这一观点，任务中使用了上肢 CRPS 患者的触觉（即身体）或视觉（即身体外）刺激。TOJ 任务可以描述认知偏差，即对空间的任一侧面有利。虽然触觉 TOJ 任务没有显示出任何显著的结果，但在视觉 TOJ 任务中观察到了显著的认知偏差，主要影响了对患病肢体附近的视觉刺激的感知。我们的研究结果清楚地表明，CRPS 存在视空间缺陷，支持皮质对 CRPS 病理生理学的贡献，并支持开发修改视空间能力的康复技术来治疗慢性疼痛的有效性。
