Zajac David J, Weissler Mark C
Craniofacial Center, University of North Carolina, Chapel Hill, NC 27599, USA.
J Speech Lang Hear Res. 2004 Aug;47(4):784-801. doi: 10.1044/1092-4388(2004/059).
Two studies were conducted to evaluate short-latency vocal tract air pressure responses to sudden pressure bleeds during production of voiceless bilabial stop consonants. It was hypothesized that the occurrence of respiratory reflexes would be indicated by distinct patterns of responses as a function of bleed magnitude. In Study 1, 19 adults produced syllable trains of "puh" using a mouthpiece coupled to a computer-controlled perturbator. The device randomly created bleed apertures that ranged from 0 to 40 mm2 during production of the 2nd or 4th syllable of an utterance. Although peak oral air pressure dropped in a linear manner across bleed apertures, it averaged 2 to 3 cm H2O at the largest bleed. While slope of oral pressure also decreased in a linear trend, duration of the oral pressure pulse remained relatively constant. The patterns suggest that respiratory reflexes, if present, have little effect on oral air pressure levels. In Study 2, both oral and subglottal air pressure responses were monitored in 2 adults while bleed apertures of 20 and 40 mm2 were randomly created. For 1 participant, peak oral air pressure dropped across bleed apertures, as in Study 1. Subglottal air pressure and slope, however, remained relatively stable. These patterns provide some support for the occurrence of respiratory reflexes to regulate subglottal air pressure. Overall, the studies indicate that the inherent physiologic processes of the respiratory system, which may involve reflexes, and passive aeromechanical resistance of the upper airway are capable of developing oral air pressure in the face of substantial pressure bleeds. Implications for understanding speech production and the characteristics of individuals with velopharyngeal dysfunction are discussed.
进行了两项研究，以评估在发清辅音双唇塞音时，声道气压对突然压力释放的短潜伏期反应。研究假设，呼吸反射的发生将通过作为压力释放幅度函数的不同反应模式来表明。在研究1中，19名成年人使用连接到计算机控制扰动器的吹口发出“puh”的音节串。该设备在话语的第二个或第四个音节产生过程中随机创建范围从0到40平方毫米的压力释放孔。尽管口腔峰值气压随着压力释放孔的增大呈线性下降，但在最大压力释放时平均为2至3厘米水柱。虽然口腔压力的斜率也呈线性下降趋势，但口腔压力脉冲的持续时间保持相对恒定。这些模式表明，呼吸反射（如果存在）对口腔气压水平影响很小。在研究2中，在2名成年人中监测口腔和声门下气压反应，同时随机创建20和40平方毫米的压力释放孔。对于1名参与者，口腔峰值气压像在研究1中一样随着压力释放孔的增大而下降。然而，声门下气压和斜率保持相对稳定。这些模式为呼吸反射调节声门下气压的发生提供了一些支持。总体而言，研究表明，呼吸系统的固有生理过程（可能涉及反射）以及上呼吸道的被动空气机械阻力能够在面对大量压力释放时产生口腔气压。讨论了对理解言语产生以及腭咽功能障碍个体特征的意义。
