Dyscognition in chronic pain. A systematic approach to cognitive complaints, cognitive performance, metamemory and malingering in patients suffering from chronic pain

尽管慢性疼痛状态非常普遍，但疼痛慢性化的潜在神经生物学机制仍然不完全清楚。越来越多的证据表明，慢性疼痛与（不适应的）大脑神经可塑性变化有关。慢性疼痛患者常伴有其他主诉和症状，如抑郁发作、慢性疲劳和认知缺陷。后者，也被称为认知障碍，越来越多的人认识到它会显著增加慢性疼痛患者的痛苦和功能障碍程度。另一方面，有证据表明，记忆抱怨（根据病人自己的估计）超过了神经心理学测试确定的实际缺陷。因此，元记忆功能障碍和装病等其他机制也可能起作用。认知障碍已经在纤维肌痛患者中进行了一些深入的研究，然而，在其他慢性疼痛状态下，如慢性头痛、慢性神经性疼痛和慢性背痛（以及其他），还需要更多的工作来确定不同疼痛综合征的认知障碍特征的异同。此外，认知障碍的神经相关性，即慢性疼痛与认知功能（如注意力、工作记忆和长期记忆）之间的相互作用，只得到很少的研究。目前的理论，这里指的是神经可塑性理论，有限资源理论和神经递质理论提供了一个概念框架，但需要进一步的证实和完善。当前提案的目的有三个。首先，需要更多的研究来描述慢性疼痛状态下的认知障碍（除了纤维肌痛）。问题是，患有慢性头痛、慢性神经性疼痛和慢性背痛的患者是否也表现出认知缺陷，如果是的话，是在哪些领域。此外，现代脑成像使研究疼痛感知和认知表现的神经相关性成为可能。目前的建议旨在使用现代脑成像技术，如结构和功能MRI，来研究与疼痛相关的大脑结构和/或功能的变化，这些变化可能影响/干扰认知功能。我们还将研究慢性疼痛的元记忆过程及其神经相关性，试图确定慢性疼痛患者如何判断他们的认知表现，以及是否存在可能导致认知功能障碍高估的负面偏见。最后，我们将调查认知缺陷（如果存在）是否随着疼痛的改善而解决。

Although chronic pain states are highly prevalent, the underlying neurobiological mechanisms of pain chronification are still incompletely understood. Increasing evidence suggests that chronic pain is associated with (maladaptive) neuroplastic changes in the brain. Chronic pain patients often suffer from additional complaints and symptoms, such as depressive episodes, chronic fatigue and cognitive deficits. The latter, also termed dyscognition, is increasingly recognized to add significantly to the degree of suffering and malfunctioning in chronic pain patients. On the other hand there is evidence that memory complaints (as estimated by the patients themselves) exceed the actual deficits as determined by neuropsychological testing. As such other mechanisms such as a dysfunction of meta-memory and malingering might also play a role. Dyscognition has been investigated in some depth in fibromyalgia patients, however more work is needed in other chronic pain states, such as chronic headaches, chronic neuropathic pain and chronic backpain (among others) to determine similarities and differences in dyscognitive profiles across pain syndromes. Furthermore neural correlates of dyscognition, i.e. the interaction between chronic pain and cognitive functions such as attention, working memory and long-term memory, have only sparsely been investigated. Current theories, here referred to as neuroplasticity theory, limited resource theory and neurotransmitter theory provide a conceptual framework, however further corroborations and refinements are needed. The aims of the current proposal are threefold. First of all more research is needed to profile dyscognition in chronic pain states (other than fibromyalgia). The question is whether patients with chronic headaches, chronic neuropathic pain and chronic back pain also show cognitive deficits, and, if so, in which domains. Furthermore modern brain imaging enables the investigation of neural correlates of both pain perception and cognitive performance. The current proposal aims at using modern brain imaging techniques, such as structural and functional MRI, to investigate changes in brain structure and/or function associated with pain that might influence/interfere with cognitive functioning. We will also investigate meta-memory processes in chronic pain paints and neural correlates thereof, trying to determine how chronic pain patients judge their cognitive performance and whether there is a negative bias that possibly leads to an overestimation of cognitive dysfunction. Finally we will investigate whether cognitive, deficits (if present) resolves, as pain improves.