Examination of the effect of ultrasonic wave in a forest environment on relieving fatigue.

本研究考察了在森林环境中聆听超声波声对缓解疲劳的影响。第一项研究（n=20），采用快速傅里叶变换（FFT）分析静息状态下脑电功率谱（F7、F8、C3、C4、P3、P4、T5、T6）。结果表明，超声声（超声波状态）在前部和中部区域的β功率高于可听范围内的声音（正常状态）。在第二项研究中（n=28），在脑力工作（视觉搜索任务）后，在每种情况下收集唾液样本。超声条件下唾液IgA浓度略有升高。这些结果表明，虽然听超声波并不会强烈地诱发放松状态，但接触这种声音可能会增加大脑额叶和中央的活动。

The present study examined effects of listening ultrasonic wave sound contained in a forest environment on relieving fatigue. In the first research (n=20), the EEG power spectrum (F7, F8, C3, C4, P3, P4, T5, T6) in resting was analyzed by Fast Fourier Transformation (FFT). Results indicated that listening to ultrasonic wave sound (ultrasonic wave condition) showed higher beta power in front and central areas than listening to sound in audibility range (normal condition). In the second research (n=28), salivary samples were collected in each condition after a mental workload (a visual search task). The concentration of salivary IgA increased slightly in the ultrasound wave condition. These results suggested that although states of relaxation were not strongly induced by a listening to ultrasound wave sound, exposure of the sound may increase the frontal and central brain activity.