Correlation Analysis of the EEG Signals in Normal and Pathological Cases

The activity of brain expressed by electrical cortical signals, the electroencephalogram (EEG) is a result of a multitude of intra and inter-hemispheric correlated sources. The correlation means quantification of the degree of association between apparently different signals, with regard to parameters they depend on. In this work, the analysis refers to the EEG activity; the relative power of the signal, dependent on frequency and location of cortical areas is assessed in normal and pathological cases. Signal acquisition and primary processing was performed with a Bio Script Zwonitz 2000 electroencephalography equipment. Standard 10-20 electrodes positioning system (with 19 electrodes) is used and the cortical activity is illustrated by signals with a spectral content within the range of 0-62 Hz. Data analyzed in the study comes from numerous normal and pathological subjects. After numerical processing, the results are shown in colored maps, in a suggestive manner, enhancing the patterns of correlation specific to normal versus pathological states. That type of data processing is useful when different pathologies need to be monitored and assessed in time.