Statistical approach to detect the presence of phase coupling using the bispectrum

The bispectrum is a method to detect the presence of phase coupling between different components in a signal. The traditional way to quantify phase coupling is by means of the bicoherence index, which is essentially a normalized bispectrum. The major drawback of the bicoherence index is that determination of the phase coupling threshold is arbitrary. To overcome this limitation, a statistical approach which combines the use of the bispectrum with a surrogate data method to determine the statistical significance of the phase coupling is introduced. We demonstrate the accuracy of the proposed approach using simulation examples which are designed to test its robustness against noise contamination as well as varying levels of phase coupling. Our results show that the proposed approach outperforms the bicoherence index and provides an unbiased and statistical approach to determining the presence of the phase coupling.