1997 Volume 35 Issue 4 Pages 392-399
Awake background EEG represents the fundamental, spontaneous brain activities, and therefore it serves as one of the most important parameters for the EEG interpretation. Specially, characteristics of slow waves of δ and θ frequency range play an important role in the electroencephalographer's visual inspection as an index to show the degree of abnormality of brain function. In this paper, the rhythmicity of the slow wave characteristics was analyzed by using an EEG model of the sinusoidal waves with Markov process amplitudes which had been proposed by the authors previously. EEGs recorded from 15 subjects were modeled by the EEG model. Parameters in the EEG model were determined in accordance with the electroencephalographer's judgment as to the rhythmicity of the slow waves. The coefficient of the first order Markov process and the half-width in the model were found to be the most useful parameters for the rhythmicity of the slow waves. Automatic judgment of the rhythmicity of slow waves by using those parameters showed a good agreement with the result of the visual inspection, and the effectiveness of the analysis method using the EEG models was demonstrated.
