Continuous observations of daytime EEG patterns in normal subjects under restrained conditions while sitting in...

While stabilizing (though not completely) both behavioral and environmental factors as far as possible, observations of continuous awake EEG patterns and corresponding behavioral states were made in order to investigate the level of vigilance for extended periods of time in the daytime. The subjects were requested to maintain a constant posture while sitting in an armchair or on a stool, and continuous polygraphic recordings and simultaneous TV monitoring of the subjects' behavior were carried out. Inspections of the EEG records, the rating of simultaneous behavior shown by the subjects and subsequent data analysis produced the following results: 1) From evaluations of EEGs, EOGs and EMG and ratings of the corresponding behavioral states carried out for every 30-second epoch, six types of awake EEG patterns and four types of behavioral states could be defined. There was a strong correlation between the awake EEG pattern and the behavioral state. 2) Regular 6.0-7.0 c/s theta wave trains predominantly in the frontal area were observed in 16 out of 24 normal subjects (67%) in an awake state. In the theta-appearance group, the relative abundance and mode of appearance of theta wave trains varied greatly both intra- and interindividually. The appearance of the theta wave trains was not related to drowsiness and was presumed to reflect the emotional activity under higher levels of vigilance in the subjects.