Rate modulation abilities & motor speech disorders (Utianski et al., 2023)

<strong>Purpose: </strong>The purpose of this study was to describe, compare, and understand speech modulation capabilities of patients with varying motor speech disorders (MSDs) in a paradigm in which patients made highly cued attempts to speak faster or slower. <strong>Method: </strong>Twenty-nine patients, 12 with apraxia of speech (AOS; four phonetic and eight prosodic subtype), eight with dysarthria (six hypokinetic and two spastic subtype), and nine patients without any neurogenic MSD completed a standard motor speech evaluation where they were asked to repeat words and sentences, which served as their “natural” speaking rate. They were then asked to repeat lower complexity (counting 1–5; repeating “cat” and “catnip” 3 times each) and higher complexity stimuli (repeating “catastrophe” and “stethoscope” 3 times each and “My physician wrote out a prescription” once) as fast/slow as possible. Word durations and interword intervals were measured. Linear mixed-effects models were used to assess differences related to MSD subtype and stimuli complexity on bidirectional rate modulation capacity as indexed by word duration and interword interval. Articulatory accuracy was also judged and compared. <strong>Results: </strong>Patients with prosodic AOS demonstrated a reduced ability to go faster; while they performed similarly to patients with spastic dysarthria when counting, patients with spastic dysarthria were able to increase rate similar to controls during sentence repetition; patients with prosodic AOS could not and made increased articulatory errors attempting to increase rate. AOS patients made more articulatory errors relative to other groups, regardless of condition; however, their percentage of errors reduced with an intentionally slowed speaking rate. <strong>Conclusions: </strong>The findings suggest comparative rate modulation abilities in conjunction with their impact on articulatory accuracy may support differential diagnosis between healthy and abnormal speech and among subtypes of MSDs (i.e., type of dysarthria or AOS). Findings need to be validated in a larger, more representative cohort encompassing several types of MSDs. <strong>Supplemental Material S1. </strong>Numerical results of linear mixed effects models. <strong>Supplemental Material S2. </strong>The fastest and slowest durations for each group. Utianski, R. L., Duffy, J. R., Martin, P. R., Clark, H. M., Stierwalt, J. A. G., Botha, H., Ali, F., Whitwell, J. L., &amp; Josephs, K. A. (2023). Rate modulation abilities in acquired motor speech disorders. <em>Journal of Speech, Language, and Hearing Research</em>. Advance online publication. https://doi.org/10.1044/2022_JSLHR-22-00286 <strong>Publisher Note:</strong> This article is part of the Special Issue: Select Papers From the 2022 Conference on Motor Speech.

**研究目的**：本研究旨在通过让不同类型运动言语障碍（motor speech disorders, MSD）患者按照高度提示的方式尝试加快或减慢语速，描述、对比并理解此类患者的言语调节能力。
**方法**：本研究共纳入29名受试者，其中12名患有言语失用症（apraxia of speech, AOS；4名语音亚型、8名韵律亚型）、8名患有构音障碍（dysarthria；6名运动过少型、2名痉挛型亚型），另有9名无任何神经源性运动言语障碍的健康受试者。所有受试者先完成标准运动言语评估：被要求重复单词与句子，以此作为其“自然”语速。随后，要求受试者以尽可能快/慢的语速重复低复杂度刺激（计数1–5；重复“cat”与“catnip”各3次）与高复杂度刺激（重复“catastrophe”与“stethoscope”各3次，并重复“My physician wrote out a prescription”1次）。本研究测量了单词时长与词间间隔，并采用线性混合效应模型，以单词时长和词间间隔为指标，评估运动言语障碍亚型与刺激复杂度对双向语速调节能力的影响；同时对发音准确性进行评判与对比。
**结果**：韵律亚型言语失用症患者表现出加快语速的能力受损；在计数任务中，其表现与痉挛型构音障碍患者相近，但痉挛型构音障碍患者在句子重复任务中可实现与健康对照组相似的语速提升，而韵律亚型言语失用症患者则无法做到，且在尝试加快语速时会出现更多发音错误。相较于其他组别，言语失用症患者无论在何种任务条件下均会产生更多发音错误；但当刻意减慢语速时，其错误率会有所降低。
**结论**：本研究结果表明，不同群体的语速调节能力及其对发音准确性的影响，可用于区分健康与异常言语，以及鉴别运动言语障碍的亚型（即构音障碍类型或言语失用症亚型）。未来需在涵盖多种运动言语障碍类型的更大规模、更具代表性的队列中验证本研究发现。
**补充材料S1**：线性混合效应模型的数值结果。
**补充材料S2**：各组别最快与最慢时长数据。
Utianski, R. L., Duffy, J. R., Martin, P. R., Clark, H. M., Stierwalt, J. A. G., Botha, H., Ali, F., Whitwell, J. L., & Josephs, K. A. (2023). 获得性运动言语障碍患者的语速调节能力. 《言语、语言与听力研究杂志》, 在线优先出版. https://doi.org/10.1044/2022_JSLHR-22-00286
**出版者注**：本文属于特刊“2022年运动言语会议精选论文”的一部分。