Department of Speech, Language and Hearing Sciences, Boston University, MA.
Department of Biomedical Engineering, Boston University, MA.
J Speech Lang Hear Res. 2019 Oct 25;62(10):3679-3688. doi: 10.1044/2019_JSLHR-S-19-0167. Epub 2019 Oct 2.
Purpose This study aimed to test whether (and how) somatosensory feedback signals from the vocal tract affect concurrent unimodal visual speech perception. Method Participants discriminated pairs of silent visual utterances of vowels under 3 experimental conditions: (a) normal (baseline) and while holding either (b) a bite block or (c) a lip tube in their mouths. To test the specificity of somatosensory-visual interactions during perception, we assessed discrimination of vowel contrasts optically distinguished based on their mandibular (English /ɛ/-/æ/) or labial (English /u/-French /u/) postures. In addition, we assessed perception of each contrast using dynamically articulating videos and static (single-frame) images of each gesture (at vowel midpoint). Results Engaging the jaw selectively facilitated perception of the dynamic gestures optically distinct in terms of jaw height, whereas engaging the lips selectively facilitated perception of the dynamic gestures optically distinct in terms of their degree of lip compression and protrusion. Thus, participants perceived visible speech movements in relation to the configuration and shape of their own vocal tract (and possibly their ability to produce covert vowel production-like movements). In contrast, engaging the articulators had no effect when the speaking faces did not move, suggesting that the somatosensory inputs affected perception of time-varying kinematic information rather than changes in target (movement end point) mouth shapes. Conclusions These findings suggest that orofacial somatosensory inputs associated with speech production prime premotor and somatosensory brain regions involved in the sensorimotor control of speech, thereby facilitating perception of concordant visible speech movements. Supplemental Material https://doi.org/10.23641/asha.9911846.
目的 本研究旨在测试来自声道的躯体感觉反馈信号是否（以及如何）影响同时进行的单模态视觉言语感知。 方法 参与者在 3 种实验条件下辨别元音的无声视觉对：（a）正常（基线）和（b）用咬块或（c）用唇管咬住嘴。为了测试感知过程中躯体感觉-视觉相互作用的特异性，我们评估了基于下颌（英语 /ɛ/-/æ/）或唇（英语 /u/-法语 /u/）姿势光学区分的元音对比的辨别力。此外，我们使用动态发音视频和每个姿势的静态（单帧）图像（在元音中点）评估了每个对比的感知。 结果 选择性地使下巴运动选择性地促进了根据下巴高度光学区分的动态姿势的感知，而选择性地使嘴唇运动选择性地促进了根据嘴唇压缩和突出程度光学区分的动态姿势的感知。因此，参与者根据自己声道的配置和形状感知可见言语运动（可能还包括他们产生隐蔽元音产生样运动的能力）。相比之下，当说话人脸不移动时，参与发音器官的运动没有影响，这表明躯体感觉输入影响时间变化的运动学信息的感知，而不是目标（运动终点）口形的变化。 结论 这些发现表明，与言语产生相关的口面部躯体感觉输入使参与言语运动感觉运动控制的运动前和躯体感觉脑区被激活，从而促进了对一致的可见言语运动的感知。 补充材料 https://doi.org/10.23641/asha.9911846.
