AUTHOR=Li Chen , Wang Yong , Li Wende , Yang Yi , Xia Xiaoyu 

TITLE=Measure functional network and cortical excitability in post-anoxic patients with unresponsive wakefulness syndrome diagnosed by behavioral scales

JOURNAL=Frontiers in Neuroscience

VOLUME=Volume 16 - 2022

YEAR=2023

URL=https://www.frontiersin.org/journals/neuroscience/articles/10.3389/fnins.2022.1071594

DOI=10.3389/fnins.2022.1071594

ISSN=1662-453X

ABSTRACT=Background：
Brain assessment shows great values in prognosis, treatment, resource allocation and decisions making for patients with disorders of consciousness (DOC). However, less research focused on cortical conditions of patients with unresponsive wakefulness syndrome (UWS). 
Methods:
We recorded resting-state EEG and TMS-EEG from post-anoxic UWS patients, diagnosed by repeated Coma Recovery Scale-Revised (CRS-R). Measurements  of functional connectivity and networks was performed by phase lock value (PLV) and networks parameters of graph theory (average path length, clustering coefficient and small-world). Global cortical reactivity values (GCRV) were used to assess cortical excitability.
Results:
The coefficient  of variation (CV) presented marked inter-individual variations of PLV (CV = 0.285), network parameters (CV > 0.2) and GCRV (CV = 0.929) within these patients. The patients’ PLV and network parameters at theta and alpha bands significantly correlated with their GCRV values. Patients with higher PLV (r = 0.560, 0.406), as well as better preserved network (lower average path length (r = -0.522, -0.483), higher clustering coefficient (r = 0.522, 0.445) and small-world (r = 0.522, 0.445)) at theta and alpha bands presented higher GCRV. The functional connectivity, which significantly correlated to frontal GCRV, also mainly located at the frontal region. These correlations were not significant at other frequency bands: delta, beta and gamma bands. 
Conclusion:
These findings suggested that the CRS-R diagnosed post-anoxic UWS patients had very different cortical conditions. Functional networks and cortical excitability measured by TMS-EEG could complement behavioural assessment to assess these patients’ cortical conditions.