A NEW NORMALISED SHORT TIME PDC FOR DYNAMIC COUPLING ANALYSES

Partial Directed Coherence (PDC) method and its extensions proved to be useful tools in analysing couplings in multivariate dynamic systems. We introduced the normalised short time PDC method (NST-PDC), to investigate the dynamic behaviour of couplings. First simulated signals obtained from coupled oscillators were analysed and information about the dynamical behaviour of the virtual system achieved. Then, as a first preliminary test applying the NST-PDC method, we observed significant (p<0.05) coupling dynamics differences in pregnant woman with hypertensive disorders, by comparing patients with preeclampsia and chronic hypertension. The NST-PDC is applicable for nonstationary time series, detects dynamical changes of coupling and might be usable for the analysis of time dependent cardiovascular couplings.