Department of Speech-Language-Hearing: Sciences & Disorders, University of Kansas, Lawrence KS, USA.
Department of Speech-Language-Hearing: Sciences & Disorders, University of Kansas, Lawrence KS, USA; Department of Hearing & Speech, University of Kansas Medical Center, Kansas City, KS, USA.
J Commun Disord. 2022 Sep-Oct;99:106253. doi: 10.1016/j.jcomdis.2022.106253. Epub 2022 Aug 13.
As a key control variable, duration has been long suspected to mediate the organization of speech motor control strategies, which has management implications for neuromotor speech disorders. This study aimed to experimentally delineate the role of duration in organizing speech motor control in neurologically healthy and impaired speakers using a voluntary speaking rate manipulation paradigm.
Thirteen individuals with amyotrophic lateral sclerosis (ALS) and 10 healthy controls performed a sentence reading task three times, first at their habitual rate, then at a slower rate. A multimodal approach combining surface electromyography, kinematic, and acoustic technologies was used to record jaw muscle activities, jaw kinematics, and speech acoustics. Six muscular-kinematic features were extracted and factor-analyzed to characterize the organization of the mandibular control hierarchy. Five acoustic features were extracted, measuring the spectrotemporal properties of the diphthong /ɑɪ/ and the plosives /t/ and /k/.
The muscular-kinematic features converged into two interpretable latent factors, reflecting the level and cohesiveness/flexibility of mandibular control, respectively. Voluntary rate reduction led to a trend toward (1) finer, less cohesive, and more flexible mandibular control, and (2) increased range and decreased transition slope of the diphthong formants, across neurologically healthy and impaired groups. Differential correlations were found between the rate-elicited changes in mandibular control and acoustic performance for neurologically healthy and impaired speakers.
The results provided empirical evidence for the long-suspected but previously unsubstantiated role of duration in (re)organizing speech motor control strategies. The rate-elicited reorganization of muscular-kinematic control contributed to the acoustic performance of healthy speakers, in ways consistent with theoretical predictions. Such contributions were less consistent in impaired speakers, implying the complex nature of speaking rate reduction in ALS, possibly reflecting an interplay of disease-related constraints and volitional duration control. This information may help to stratify and identify candidates for the rate manipulation therapy.
作为一个关键的控制变量，时长一直被怀疑调节言语运动控制策略的组织，这对神经运动性言语障碍的管理具有启示意义。本研究旨在通过自愿语速调节范式，实验性地阐明时长在调节神经健康和受损说话者言语运动控制中的作用。
13 名肌萎缩性侧索硬化症（ALS）患者和 10 名健康对照者进行了三次句子阅读任务，第一次以他们的习惯语速，然后以较慢的语速进行。采用表面肌电图、运动学和声学技术相结合的多模态方法记录下颌肌肉活动、下颌运动学和言语声学。提取了六个肌肉运动特征，并进行因子分析，以描述下颌控制层次的组织。提取了五个声学特征，用于测量双元音/ɑɪ/和爆破音/t/和/k/的频谱时变特性。
肌肉运动特征收敛为两个可解释的潜在因素，分别反映了下颌控制的水平和内聚性/灵活性。自愿降速导致（1）更精细、不内聚和更灵活的下颌控制，以及（2）在神经健康和受损组中，双元音共振峰的范围增加，过渡斜率减小。在神经健康和受损说话者中，发现下颌控制和声学性能之间的速率诱发变化之间存在差异相关性。
结果为时长在（重新）组织言语运动控制策略中所起的长期怀疑但以前未证实的作用提供了经验证据。肌肉运动控制的速率诱发重组有助于健康说话者的声学表现，其方式与理论预测一致。在受损说话者中，这种贡献不太一致，这意味着 ALS 中语速降低的复杂性，可能反映了疾病相关限制和自愿时长控制的相互作用。这些信息可能有助于分层并确定适合速率调节治疗的候选者。
