A New Method for Brain Death Diagnosis Based on Phase Synchronization Analysis With EEG

Although brain death has been accepted by most countries, how to diagnose brain death quickly and accurately is still a very challenging task. Electroencephalography (EEG) is considered to be one of the most effective methods for clinically diagnosing the brain state. In the present study, we investigated if it is possible to find a robust neuro-marker to help doctors diagnose brain death from the perspective of brain information interaction. With 6-channel EEG data collected from prefrontal lobe of 30 patients (deep coma: 13, brain death 17), PLV was used to measure the phase synchronization and quantify the interaction between brain regions. Firstly, we found that there exists significant difference in brain synchronization between brain death patients and deep coma patients. Then, an interesting phenomenon was observed. In all the three low frequency bands (delta, theta, alpha), synchronization between the left hemisphere and the right hemisphere (IHPS) is significantly stronger than that only in left (LHPS) or right hemisphere (RHPS) for deep coma patients. However, this phenomenon has not been found in high frequency bands (beta and gamma) and for brain death patients. More importantly, it was verified for almost every patient (only 1 exception). This phenomenon might provide a robust neuro-marker for brain death diagnosis. Finally, we tried to distinguish between brain death and brain coma by monitoring brain synchronization in real time. The results also show the effectiveness and accuracy of our method. The method proposed in this paper can not only provide doctors with more stable and effective information, but also hope to develop a new visualization tool to assist brain death diagnosis.