Early EEG correlates of neuronal injury after brain anoxia

Feasibility of Reconstructing Source Functional Connectivity with Low-Density EEG

OBJECTIVES

Functional connectivity (FC) is increasingly used as target for neuromodulation and enhancement of performance. A reliable assessment of FC with electroencephalography (EEG) currently requires a laboratory environment with high-density montages and a long preparation time. This study investigated the feasibility of reconstructing source FC with a low-density EEG montage towards a usage in real life applications.

METHODS

Source FC was reconstructed with inverse solutions and quantified as node degree of absolute imaginary coherence in alpha frequencies. We used simulated coherent point sources as well as two real datasets to investigate the impact of electrode density (19 vs. 128 electrodes) and usage of template vs. individual MRI-based head models on localization accuracy. In addition, we checked whether low-density EEG is able to capture inter-individual variations in coherence strength.

RESULTS

In numerical simulations as well as real data, a reduction of the number of electrodes led to less reliable reconstructions of coherent sources and of coupling strength. Yet, when comparing different approaches to reconstructing FC from 19 electrodes, source FC obtained with beamformers outperformed sensor FC, FC computed after independent component analysis, and source FC obtained with sLORETA. In particular, only source FC based on beamformers was able to capture neural correlates of motor behavior.

CONCLUSION

Reconstructions of FC from low-density EEG is challenging, but may be feasible when using source reconstructions with beamformers.

Value of Continuous Video EEG and EEG Responses to Thermesthesia Stimulation in Prognosis Evaluation of Comatose Patients after Cardiopulmonary Resuscitation

Objective

To investigate the clinical value of video-electroencephalography (VEEG) and thermal stimulus on evaluating the prognosis of comatose patients after cardiopulmonary resuscitation.

Methods

Twenty eight comatose patients with cardiopulmonary resuscitation were included in the department of ICU of the First Teaching Hospital of Fujian Medical University from February 2013 to March 2016. Of the included 28 patients, 20 cases died (death group) and 8 cases survived (survival group) after cardiopulmonary resuscitation. The VEEG, Glasgow Coma Scale (GCS) and APACHE II score were recorded and compared between the death and survival group. The prediction value of death for VEEG, GCS and APACHE II were evaluated through sensitivity, specificity and area under the receiver operating characteristic (ROC) curve (AUC).

Results

GCS and APACHEH II score were statistical different between the death and survival group (P<0.05). With the increase of VEEG grading, the mortality rate of patients increased significantly (P<0.05). Predicting value of mortality for GCS, VEEG and APACHEH II were 57.69%, 61.54% and 71.43% respectively without statistical difference (P>0.05). The death prediction sensitivity and specificity for GCS were 67.0% and 85.0%, for APACHEH II were 95.1% and 85.0%, for VEEG were 100.0% and 85.2%. VEEG has the highest sensitivity, Specificity, coincidence rate and Kappa vale compared to GCS, and APACHEH II.

Conclusion

Video-electroencephalography is a useful tool for predicting the death risk for patients who received cardiopulmonary resuscitation.