Physiological Response to Unpleasant Sounds

Using electroencephalograms (EEGs), we studied physiological response quantification towards unpleasant sounds. We especially examined personal difference, repeatability and fixed quantity nature of EEGs in three experiments. Results from EEG analysis regarding personal difference hinted at the possibility that a combination of sound frequencies caused an unpleasant sound environment, not a monofrequency component sound. As for repeatability, the siren sound of a fire truck and white noise significantly decreased alpha rhythm, and because a significant difference was recognized for the alpha rhythm for pleasant sounds, we thought stress of a living organism was shown. In addition, EEG data collected at a 1-week interval and EEG data collected for three continuous measurements on one day showed high reliability. EEGs negatively correlated with blood pressure (BP) and not with arterial oxygen saturation (SPO2).