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

在这项研究中，我们使用血流反应的非侵入性生理测量来提供证据，证明婴儿哭声包含高于可听范围的高频分量(HFC)显著影响哺乳期母亲的乳房血流。当HFC单独呈现时，没有一个受试者认为HFC是声音。然而，与去除HFC的相同声音相比，当受试者暴露在全音域声音中时，使用NIRS(近红外立体观察法)从双侧乳房记录的氧合血红蛋白浓度值显著增加。生理评估表明，受试者感觉到婴儿的哭声在意识水平以下含有HFC。在哺乳建立期间，这对母子之间的正常生物交流可能很重要。

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.