Synchronization Analysis of EEG Using the Hilbert Huang Coherence

The short periods of synchronization of different brain regions in particular frequency ranges during cognitive activities is reported. In this study, the Hilbert Huang Coherence (HHC) for analyzing the degree of synchronization by using a Hilbert Huang transform with high temporal frequency resolution is proposed. The authors intended to verify the availability of the HHC. According to computer simulation, it was found that temporal frequency resolution of HHC is higher than that of traditional coherence analysis for non-stationary signals. Furthermore, the HHC was applied to EEG during closed eyes rest. As results of them, the change of coherence in \( \alpha \) band was obtained higher temporal frequency resolution than that of traditional coherence analysis.