Inaudible high-frequency components of infant crying affect the breast hemodynamics of lactating mothers

在这项研究中，我们使用无创生理测量血流反应来提供证据，证明婴儿哭声中含有高于可听范围的高频成分（HFCs）会显著影响哺乳期母亲的乳房血流。当HFC单独出现时，没有一个受试者认出它是声音。然而，当受试者暴露在全音域的声音中时，使用近红外立体成像（NIRS）从两个乳房记录的氧血红蛋白浓度值明显高于去除HFC的其他相同声音。生理评价表明，受试者感受到的婴儿哭声中含有低于意识水平的HFC。在哺乳期建立期间，这可能对母亲和孩子之间的正常生物交流很重要。

In this study, we used noninvasive physiological measurement of blood flow responses to provide evidence that infant crying sounds containing high-frequency components (HFCs) above the audible range significantly affect the breast blood flow of lactating mothers. None of the subjects recognized the HFC as sound when it was presented alone. Nevertheless, the values of oxy-hemoglobin concentration using NIRS (near-infrared stereoscopy) recorded from the both breasts significantly increased when the subjects were exposed to full-range sound compared with an otherwise identical sound from which the HFC was removed. Physiological evaluation indicates that the subjects felt the infant crying sounds containing an HFC below the level of consciousness. It might be important for normal biological communication between mother and child during the period when lactation is establishing.