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

Chen Li; Yong Wang; Wende Li; Yi Yang; Xiaoyu Xia

doi:10.3389/fnins.2022.1071594

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

Front Neurosci. 2023 Jan 11:16:1071594. doi: 10.3389/fnins.2022.1071594. eCollection 2022.

Authors

Chen Li¹, Yong Wang², Wende Li^{3

4}, Yi Yang⁵, Xiaoyu Xia^{3

4}

Affiliations

¹ Department of Interventional and Vascular Neurosurgery, The Characteristic Medical Center of People's Liberation Army (PLA) Rocket Force, Beijing, China.
² Zhuhai University of Macau (UM) Science & Technology Research Institute, Zhuhai, China.
³ Senior Department of Neurosurgery, The First Medical Center of People's Liberation Army (PLA) General Hospital, Beijing, China.
⁴ Department of Neurosurgery, The Seventh Medical Center of People's Liberation Army (PLA) General Hospital, Beijing, China.
⁵ Department of Neurosurgery, Beijing Tiantan Hospital, Beijing, China.

Abstract

Background: Brain assessment shows great values in prognosis, treatment, resource allocation, and decision-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 patients with UWS, diagnosed by repeated Coma Recovery Scale-Revised (CRS-R). Measurements of functional connectivity and networks were performed by phase lock value (PLV) and network 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 is significantly correlated with frontal GCRV, is also mainly located in 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 patients with UWS had very different cortical conditions. Functional networks and cortical excitability measured by TMS-EEG could complement behavioral assessment to assess these patients' cortical conditions.

Significance: It provides a deeper understanding of neurophysiological dysfunction in patients with UWS and hints to the clinics that neural-electrophysiological assessment for such patients may be necessary to acquire their brain conditions, which may benefit stratified management for them.

Keywords: TMS-EEG; functional connectivity; global mean field amplitude; graph theory; unresponsive wakefulness syndrome.

Grants and funding

This study was supported by the National Natural Science Foundation of China (grant numbers: 6182780069 and 61761166003), the Beijing Municipal Science & Technology Commission (grant number: Z171100001017162), and the Medicine and Health Science and Technology Project of Zhejiang Province (grant number: 2019310106).