Fractal dimension methods to determine optimum EEG electrode placement for concentration estimation

In this study, fractal dimension approaches were used for analyzing EEG to determine the optimum electrode placement to distinguish between concentration and relaxation states. The EEG of five subjects were recorded from multiple electrode placements while under relaxed state, and while in a state of heightened mental activity. Higuchi and Katz algorithms were applied to extract the FD indices of the EEG signals at 1-second intervals. These were then plotted in a graph and a simple linear regression was applied. The resulting ROC curve was used to determine the best electrode placement for distinguishing between relaxed and concentration brain states. The Katz algorithm performed slightly better than the Higuchi method. With the exception of P4, multiple electrode placements were found to be suitable for distinguishing between relaxed and concentration states, with P7 and F3 being slightly better than the rest.