患有长期意识障碍(PDOC)的个体的疼痛感知仍然是一个有争议的问题。先进的神经影像学研究表明,与具有最低意识状态(MCS)的患者相比,即使在无反应的觉醒综合征(UWS)患者中,也有一些皮质激活。因此,即使在患有UWS的个体中,也必须考虑疼痛感知。然而,先进的神经影像学评估可能具有挑战性,它的发现有时很难解释。相反,多通道脑电图(EEG)和激光诱发电位(LEP)可以快速进行,并且更适应临床需求。在这次范围审查中,我们处理了支撑PDOC疼痛的神经生理学基础,指出这些人的疼痛感知评估可能有助于降低误诊率。现有的文献数据表明,与MCS患者相比,UWS患者在疼痛相关的大脑区域中表现出更严重的功能连接破坏。指出疼痛感知随着意识水平的提高而增加。然而,有值得注意的例外,因为一些UWS患者表现出与疼痛相关的皮质激活,与MCS个体中观察到的部分重叠。这表明一些患有UWS的患者可能有残余的脑功能连接支持体感,情感,和疼痛处理的认知方面(即,对痛苦的不愉快的有意识的体验),而不是只能对潜在的有害刺激表现出自主神经反应。因此,在PDOC中神经生理学方法对疼痛感知的意义似乎很清楚,尽管有一些方法上的警告(包括刺激强度,多模态范例,和活跃的vs.被动刺激协议),还有待解决。总结一下,应始终进行准确的临床和神经生理学评估,以更好地理解疼痛感知的神经生理学基础,在单个病例和组比较的水平上进行更精确的鉴别诊断,和患者量身定制的管理。
Pain perception in individuals with prolonged disorders of consciousness (PDOC) is still a matter of debate. Advanced neuroimaging studies suggest some cortical activations even in patients with unresponsive wakefulness syndrome (UWS) compared to those with a minimally conscious state (MCS). Therefore, pain perception has to be considered even in individuals with UWS. However, advanced neuroimaging assessment can be challenging to conduct, and its findings are sometimes difficult to be interpreted. Conversely, multichannel electroencephalography (EEG) and laser-evoked potentials (LEPs) can be carried out quickly and are more adaptable to the clinical needs. In this scoping review, we dealt with the neurophysiological basis underpinning pain in PDOC, pointing out how pain perception assessment in these individuals might help in reducing the misdiagnosis rate. The available literature data suggest that patients with UWS show a more severe functional connectivity breakdown among the pain-related brain areas compared to individuals in MCS, pointing out that pain perception increases with the level of consciousness. However, there are noteworthy exceptions, because some UWS patients show pain-related cortical activations that partially overlap those observed in MCS individuals. This suggests that some patients with UWS may have residual brain functional connectivity supporting the somatosensory, affective, and cognitive aspects of pain processing (i.e., a conscious experience of the unpleasantness of pain), rather than only being able to show autonomic responses to potentially harmful stimuli. Therefore, the significance of the neurophysiological approach to pain perception in PDOC seems to be clear, and despite some methodological caveats (including intensity of stimulation, multimodal paradigms, and active vs. passive stimulation protocols), remain to be solved. To summarize, an accurate clinical and neurophysiological assessment should always be performed for a better understanding of pain perception neurophysiological underpinnings, a more precise differential diagnosis at the level of individual cases as well as group comparisons, and patient-tailored management.