基于听觉刺激的意识障碍患者脑功能连通性研究

目的 目前对意识障碍（DOC）患者的分级评估仍是相关领域的重点和难点。因效性网络可以通过时间序列间的因果关系直观地反映信息传递方向,帮助人们更好地理解患者大脑不同区域之间的信息交互作用。本文结合脑电图和因效性网络探讨听觉刺激下无反应觉醒综合征（VS）患者与最低意识状态（MCS）患者的脑功能连通性差异。方法 共纳入23例DOC患者,采集并分析唤名刺激下的脑电信号,通过多元格兰杰因果方法构建脑功能网络,利用脑网络节点度、聚类系数、全局效率以及因果流向性等参量从脑区之间协同工作的角度对比研究听觉刺激下不同意识水平患者的网络特征。结果 唤名刺激下MCS患者的脑功能连通性强于VS患者,且呈现出因果流向差异,MCS与VS患者四个脑区的信息传递方向均不相同。结论 唤名听觉刺激下MCS患者的信息传递能力强于VS患者;与VS患者相比MCS患者为因果源的电极通道数增多,对其他脑区的信息输出增多。本研究可为DOC患者意识水平的分级评估提供一定的理论依据。

A Study on Brain Functional Connectivity in Patients Disorders of Consciousness Based on Auditory Stimulation

Objective At present, the grading evaluation of patients with disorders of consciousness (DOC) is still a focus and difficulty in related fields. Electroencephalogram (EEG) can directly read and continuously reflect scalp electrical activity generated by brain tissue structure, with high temporal resolution. Auditory stimulation is easy to operate and has broad application prospects in clinical detection of DOC. The causal network can intuitively reflect the direction of information transmission through the causal relationship between time series, helping us better understand the information interaction between different regions of the brain of patients. This paper combines EEG and causal networks to explore the differences in brain functional connectivity between patients with unresponsive arousal syndrome (VS) and those with minimum state of consciousness (MCS) under auditory stimulation.Methods A total of 23 DOC patients were included, including 11 MCS patients and 12 VS patients. Based on the Oddball paradigm, auditory naming stimulation was performed on DOC patients and EEG signals of DOC patients were synchronously collected. The brain functional networks were constructed using multivariate Granger causality method, and the differences in node degree, clustering coefficient, global efficiency, and causal flow of the brain networks between MCS patients and VS patients were calculated. The differences in network characteristics of patients with different levels of consciousness under auditory stimulation were compared from the perspective of cooperation between brain regions.Results The causal connectivity between most brain regions in MCS patients was stronger than that in VS patients, and MCS patients had more brain network connectivity edges than VS patients. The average degree (P<0.05), average clustering coefficient, and global efficiency (P<0.05) of MCS patients under naming stimulation were higher than those of VS patients. The difference in out-degree between each node of VS patients was larger, and the difference in in-degree between each node of MCS patients was smaller. The difference in in-degree of MCS patients was more significant than that of VS patients, and the inflow and outflow of information in the brain functional network of MCS patients were stronger than those of VS patients. MCS and VS patients had differences of causal flow in the frontal and temporal lobes, the direction of information transmission in the parietal lobe and central region was not the same, and MCS patients had more electrodes as causal sources than VS patients.Conclusion The information transmission ability of MCS patients is stronger than that of VS patients under auditory naming stimulation. Compared with VS patients, MCS patients have an increase in the number of electrode channels as the causal source, an increase in information output to other brain regions, and also an increase in the information output within brain regions, which may indicate a better state of consciousness in patients. MCS patients have more electrode channels for information output in the frontal lobe than VS patients, and the number of electrode channels for changing the direction of information transmission in the frontal lobe is the highest. The frontal lobe is closely related to the level of consciousness in patients with consciousness disorders. This study can provide a theoretical basis for the grading evaluation of consciousness levels in DOC patients.