Human EEG responses to classical music and simulated white noise: effects of a musical loudness component on consciousness.

The main purpose of the present study was to investigate the psychophysiological effects of music on human EEG. For this purpose, a sound modulator was developed which simulates the sound-pressure variations of a given piece of music by white noise (sim-music). Using this apparatus, the author tested the psychophysiological effects of music on human EEG. The electroencephalograms (EEG), electrocardiograms (ECG), and electrooculograms (EOG) of eight normal volunteers were recorded for a total of 21 min., 5 sec. per session for each subject under three sound conditions: silence for 5 min., two types of music (music) or two types of simulated noise (sim-music) for 11 min., 5 sec., followed by silence for another 5 min. Each subject was exposed to a total of 10 music and 10 sim-music conditions. At the low consciousness level (drowsiness, Stage S1), higher delta component power densities were observed with sim-music than with music. Thus, even in the same Stage S1, entire physiological consciousness levels may be higher when listening to music than to sim-music. While listening to music, many subjects reported that they felt pleasantly relaxed or comfortable. However, with the sim-music, they reported feeling unpleasantly weary and sleepy. It seems that the mental set toward two sound conditions differed greatly for many subjects. In Stage S1, the differences in EEG slow components showed that the differences in consciousness had a physiological aspect and indicated differences in mental set toward both sound conditions and mental activity during the listening conditions.