Approximate entropy analysis of electroencephalogram in vasovagal syncope on tilt table test

Thirty vasovagal attacks on sublingual nitroglycerin stressed tilting test were selected. By the method of shifting window along the continuous EEG signals the linear (spectral power and coherence) and nonlinear (approximate entropy) EEG features of the whole course in the tilt table test were demonstrated. Of all the EEG parameters approximate entropy is a more sensitive index in clarifying stages of various degree of tilting stress and in identifying the syncopal transient.