Bonfiglio Luca, Piarulli Andrea, Olcese Umberto, Andre Paolo, Arrighi Pieranna, Frisoli Antonio, Rossi Bruno, Bergamasco Massimo, Carboncini Maria Chiara
Department of Translational Research on New Technologies in Medicine and Surgery, School of Physical Medicine and Rehabilitation, University of Pisa, Pisa, Italy.
TeCIP Institute, PERCRO Laboratory, Scuola Superiore Sant'Anna, Pisa, Italy.
PLoS One. 2014 Mar 27;9(3):e93252. doi: 10.1371/journal.pone.0093252. eCollection 2014.
Recently, the cortical source of blink-related delta oscillations (delta BROs) in resting healthy subjects has been localized in the posterior cingulate cortex/precuneus (PCC/PCu), one of the main core-hubs of the default-mode network. This has been interpreted as the electrophysiological signature of the automatic monitoring of the surrounding environment while subjects are immersed in self-reflecting mental activities. Although delta BROs were directly correlated to the degree of consciousness impairment in patients with disorders of consciousness, they failed to differentiate vegetative state/unresponsive wakefulness syndrome (VS/UWS) from minimally conscious state (MCS). In the present study, we have extended the analysis of BROs to frequency bands other than delta in the attempt to find a biological marker that could support the differential diagnosis between VS/UWS and MCS. Four patients with VS/UWS, 5 patients with MCS, and 12 healthy matched controls (CTRL) underwent standard 19-channels EEG recordings during resting conditions. Three-second-lasting EEG epochs centred on each blink instance were submitted to time-frequency analyses in order to extract the normalized Blink-Related Synchronization/Desynchronization (nBRS/BRD) of three bands of interest (low-alpha, high-alpha and low-beta) in the time-window of 50-550 ms after the blink-peak and to estimate the corresponding cortical sources of electrical activity. VS/UWS nBRS/BRD levels of all three bands were lower than those related to both CTRL and MCS, thus enabling the differential diagnosis between MCS and VS/UWS. Furthermore, MCS showed an intermediate signal intensity on PCC/PCu between CTRL and VS/UWS and a higher signal intensity on the left temporo-parieto-occipital junction and inferior occipito-temporal regions when compared to VS/UWS. This peculiar pattern of activation leads us to hypothesize that resting MCS patients have a bottom-up driven activation of the task positive network and thus are tendentially prone to respond to environmental stimuli, even though in an almost unintentional way.
最近，在静息状态下的健康受试者中，与眨眼相关的δ振荡（δBROs）的皮质源已被定位在后扣带回皮质/楔前叶（PCC/PCu），它是默认模式网络的主要核心枢纽之一。这被解释为当受试者沉浸在自我反思的心理活动中时，对周围环境进行自动监测的电生理特征。尽管δBROs与意识障碍患者的意识损害程度直接相关，但它们无法区分植物状态/无反应觉醒综合征（VS/UWS）和最低意识状态（MCS）。在本研究中，我们将对BROs的分析扩展到δ频段以外的其他频段，试图找到一种能够支持VS/UWS和MCS之间鉴别诊断的生物学标志物。4例VS/UWS患者、5例MCS患者和12名健康匹配对照（CTRL）在静息状态下接受了标准的19导脑电图记录。以每次眨眼实例为中心的持续3秒的脑电图片段进行时频分析，以便在眨眼峰值后50-550毫秒的时间窗口内提取三个感兴趣频段（低α、高α和低β）的归一化眨眼相关同步/去同步（nBRS/BRD），并估计相应的皮质电活动源。VS/UWS所有三个频段的nBRS/BRD水平均低于CTRL和MCS相关水平，从而能够对MCS和VS/UWS进行鉴别诊断。此外，与VS/UWS相比，MCS在PCC/PCu上显示出介于CTRL和VS/UWS之间的中等信号强度，在左侧颞顶枕交界区和枕颞下区显示出更高的信号强度。这种特殊的激活模式使我们推测，静息状态下的MCS患者存在任务阳性网络的自下而上驱动激活，因此即使是以几乎无意识的方式，也倾向于对环境刺激做出反应。
