Wellcome Centre for Integrative Neuroimaging, Department of Experimental Psychology, University of Oxford, Oxford, United Kingdom.
Department of Psychology, School of Human and Behavioural Sciences, Bangor University, Bangor, United Kingdom.
PLoS One. 2024 Oct 16;19(10):e0309612. doi: 10.1371/journal.pone.0309612. eCollection 2024.
Several studies indicate that people who stutter show greater variability in speech movements than people who do not stutter, even when the speech produced is perceptibly fluent. Speaking to the beat of a metronome reliably increases fluency in people who stutter, regardless of the severity of stuttering.
Here, we aimed to test whether metronome-timed speech reduces articulatory variability.
We analysed vocal tract MRI data from 24 people who stutter and 16 controls. Participants repeated sentences with and without a metronome. Midsagittal images of the vocal tract from lips to larynx were reconstructed at 33.3 frames per second. Any utterances containing dysfluencies or non-speech movements (e.g. swallowing) were excluded. For each participant, we measured the variability of movements (coefficient of variation) from the alveolar, palatal and velar regions of the vocal tract.
People who stutter had more variability than control speakers when speaking without a metronome, which was then reduced to the same level as controls when speaking with the metronome. The velar region contained more variability than the alveolar and palatal regions, which were similar.
These results demonstrate that kinematic variability during perceptibly fluent speech is increased in people who stutter compared with controls when repeating naturalistic sentences without any alteration or disruption to the speech. This extends our previous findings of greater variability in the movements of people who stutter when producing perceptibly fluent nonwords compared with controls. These results also show, that in addition to increasing fluency in people who stutter, metronome-timed speech also reduces articulatory variability to the same level as that seen in control speakers.
多项研究表明，即使口吃者的言语听起来明显流畅，他们的言语运动也比不口吃者更具可变性。在节拍器的引导下，口吃者的流畅度会显著提高，而无论口吃的严重程度如何。
我们旨在测试节拍器控制的言语是否能降低发音的可变性。
我们分析了 24 名口吃者和 16 名对照组参与者的磁共振成像（MRI）数据。参与者重复带有和不带有节拍器的句子。从嘴唇到喉咙的声道中矢状图像以 33.3 帧/秒的速度重建。排除任何包含不流畅或非言语运动（如吞咽）的发音。对于每个参与者，我们测量了声道的牙槽、腭和软腭区域的运动可变性（变异系数）。
在没有节拍器的情况下，口吃者的发音比对照组更具可变性，而在使用节拍器时，其可变性则降低到与对照组相同的水平。软腭区域的可变性大于牙槽和腭区域，而这两个区域的可变性相似。
这些结果表明，与对照组相比，在重复自然语言句子时，口吃者在感知流畅的言语中运动的可变性增加，而无需对言语进行任何改变或干扰。这扩展了我们之前的发现，即在产生感知流畅的非词时，口吃者的运动比对照组具有更大的可变性。这些结果还表明，除了提高口吃者的流畅度外，节拍器控制的言语还能将发音的可变性降低到与对照组相同的水平。
