The effect of filtering in the EEG correlation dimension estimation: experimental results
The effect of linear filtering on the estimation of the correlation dimension of the electroencephalogram (EEG) is described. Three types of filters and several bandwidths are applied to the signal and to white noise sequences, in order to measure experimentally the effect in the correlation dimension. The results show that a reduction in bandwidth does affect the correlation exponent map of white noise sequences, so that the usual way of displaying the correlation dimension, comparing it to the theoretically straight line of the white noise, is misleading. It is suggested that the plot of the correlation exponent (of the EEG or any other bandlimited signal) should be graphed with the correlation exponent of white noise for the same measurement bandwidth.<<ETX>>