DEVELOPING OF EEG PRINT AND ITS PRELIMINARY TECHNICAL APPLICATION

In this report, we discuss a method called ''EEG print'' to represent EEG contrast mapping in time and frequency domains simultaneously. A b ank of bandpass FIR (Finite Impulse Response) digital filters is used to obtain EEG prints. FEG prints were taken from four areas (F3, F4, O 1 and O2) of EEG when healthy subjects were at rest with their eyes cl osed. The pattern of the prints was classified into four types: alpha type, beta type, alpha + beta type and complex type. It was found that EEG prints may vary from person-to-person but they usually do not var y much between the four areas for a given person. The method is furthe r modified to obtain ''differential EEG prints'' to investigate whethe r meaningful higher frequency EEG components exist. Differentiation of EEG resulted in marked intensification of the fast waves, using 0.14 Hz as the critical point. In differential EEG print with higher order differentiation, amplification in the high frequency components increa se their frequency. As a result, it is possible to observe variations in the high frequency components, which are otherwise not detectable i n the usual EEG print. EEG print can be used for representing the func tion of the brain. Using the method for classification of EEG print pa tterns, described in this paper, we can clarify not only the character istics of the normal brain but also the pathophysiology of mentally-il l patients.