Application of Higuchi's Fractal Dimension for the Statistical Analysis of Human EEG Responses to Odors

The purpose of this study is to evaluate the fractal dimension (FD) analysis of pleasant-unpleasant odor EEGs. Higuchi's fractal dimension (HFD), which calculates FD directly in time domain, was preferred as a nonlinear signal analysis method. EEG recordings of 6 males were collected for dataset. Results showed that HFD values of pleasant and unpleasant odor EEGs were not in normal distribution and variances between independent variables were not homogeneous in all EEG channels. HFD values of pleasant odors were significantly different from unpleasant ones in O2 (right occipital) and T7 (left temporal) channels. There was a strong correlation between frontal lobes (F3-F4) for all class of odors. HFD values of unpleasant odors were higher than pleasant odors. It showed that unpleasant odor EEGs have more complex patterns than pleasant ones. The proposed work was performed with statistical tools.