Effect of Mobile Phone Radiation on EEG Using Various Fractal Dimension Methods

The electroencephalogram (EEG) is a record of the oscillations of brain electric potentials. The EEG provides a convenient window on the mind, revealing synaptic action that strongly co-relate with brain state. Fractal dimension, the measure of signal complexity can be used to characterize the physiological conditions of the brain. As the EEG signal is non linear, non stationary and noisy, non linear methods will be suitable for the analysis. In this paper various methods of fractal dimension analysis especially Higuichi’s fractal method, Katz, and k-NN algorithms were applied to find the fractal dimension of EEG. The main attraction of fractal geometry is its ability to describe the irregular shape of natural features as well as other complex objects that traditional Euclidean geometry fails to analyze. EEGs of 10 volunteers were recorded at rest and on exposure to radiofrequency (RF) emissions from mobile phones having different SAR values. Mobiles were positioned near the auricle and then near the Cz position. Fractal dimensions for all conditions are calculated using three algorithms. The FD of sample data sets were tested using Ftest. Null hypothesis is rejected in 70% , 90%and 90% respectively for Higuichi, Katz and k_NN for data set prepared by keeping phone at Auricle position. Similarly null hypothesis is rejected in 75%, 90%and 90% respectively for Higuichi, Katz and k_NN for data set prepared by keeping phone at auricle position. The result shows that there are some changes in the FD while using mobile phone. The change in FD of the signal varies from person to person. The changes in FD show the variations in EEG signal while using mobile phone, which demonstrate transformation in the activities of brain due to radiation.