A. Mauricio et al., A statistical technique for measuring synchronism between cortical regionsin the EEG during rhythmic stimulation, IEEE BIOMED, 48(10), 2001, pp. 1211-1215
The coherence function has been widely applied in quantifying the degree of
synchronism between electroencephalogram (EEG) signals obtained from diffe
rent brain regions. However, when applied to investigating synchronization
resulting from rhythmic stimulation, misleading results can arise from the
high correlation of background EEG activity. We, thus propose a modified me
asure, which emphasizes the synchronized stimulus responses and reduces the
influence of the spontaneous EEG activity. Critical values for this estima
tor are derived and tested in Monte Carlo simulations. The effectiveness of
the method is illustrated on data recorded from 12 young normal subjects d
uring rhythmic photic stimulation.