Stimulus length on speech stability in ALS (Teplansky et al., 2024)

Purpose: This study aimed to investigate the effect of stimulus signal length on tongue and lip motion pattern stability in speakers diagnosed with amyotrophic lateral sclerosis (ALS) compared to healthy controls.Method: Electromagnetic articulography was used to derive articulatory motion patterns from individuals with mild (n = 27) and severe (n = 16) ALS and healthy controls (n = 25). The spatiotemporal index (STI) was used as a measure of articulatory stability. Two experiments were conducted to evaluate signal length effects on the STI: (a) the effect of the number of syllables on STI values and (b) increasing lengths of subcomponents of a single phrase. Two-way mixed analyses of variance were conducted to assess the effects of syllable length and group on the STI for the tongue tip (TT), tongue back (TB), and lower lip (LL).Results: Experiment 1 showed a significant main effect of syllable length (TT, p p p p = .037; TB, p = .007; and LL, p = .017). TB and LL stability was generally higher with speech stimuli that included a greater number of syllables. Articulatory variability was significantly higher in speakers diagnosed with ALS compared to healthy controls. Experiment 2 showed a significant main effect of length (TT, p p = .015; and LL, p Conclusions: Articulatory stability is influenced by the length of speech signals and manifests similarly in both healthy speakers and persons with ALS. TT stability may be significantly impacted by phonemic content due to greater movement flexibility. Compared to healthy controls, there was an increase in articulatory variability in those with ALS, which likely reflects deviations in speech motor control.Supplemental Material S1. Main and interaction effects of length (2-, 3-, 5-, 8-syllables) and group (control, mild ALS, severe ALS) from two-way mixed ANOVA for all articulators. Statistics were performed on original data. Statistically significant effects are in bold.Supplemental Material S2. Bonferroni corrected pairwise comparisons to assess mean differences in STI with 95% confidence intervals. Statistics were performed on original data. Statistically significant differences are in bold.Supplemental Material S3. Main and interaction effects of segment length (25%, 50%, 75%, 100% of an 8-syllable phrase) and group (control, Mild ALS, Severe ALS) from two-way mixed ANOVA for all articulators. Statistics were performed on original STI values. Statistically significant effects are in bold.Supplemental Material S4. Bonferroni corrected pairwise comparisons to assess mean differences in STI values. Mean differences are provided for each articulator. Statistics were performed on original STI values. Statistically significant differences are in bold.Teplansky, K. J., Wisler, A., Goffman, L., & Wang, J. (2024). The impact of stimulus length in tongue and lip movement pattern stability in amyotrophic lateral sclerosis. Journal of Speech, Language, and Hearing Research, 67(10S), 4002–4014. https://doi.org/10.1044/2023_JSLHR-23-00079Publisher Note: This article is part of the Special Issue: Select Papers From the 8th International Conference on Speech Motor Control.

### 研究目的
本研究旨在探究刺激信号时长对确诊肌萎缩侧索硬化症（amyotrophic lateral sclerosis, ALS）患者与健康对照者的舌部及唇部运动模式稳定性的影响。
### 研究方法
本研究采用电磁发音描记法（Electromagnetic Articulography, EMA），从轻度（n=27）、重度（n=16）ALS患者及25名健康对照者中提取发音运动模式。以时空指数（spatiotemporal index, STI）作为发音稳定性的量化指标。开展两项实验以评估信号时长对STI的影响：(a) 音节数量对STI值的作用；(b) 单个短语子成分时长递增的效应。针对舌尖（tongue tip, TT）、舌背（tongue back, TB）及下唇（lower lip, LL）的STI，采用两因素混合方差分析（two-way mixed analyses of variance）检验音节时长与组别对其的影响。
### 研究结果
实验1显示音节时长存在显著主效应（TT, p = .037; TB, p = .007; LL, p = .017）。舌背与下唇的稳定性通常在包含更多音节的言语刺激中更高。与健康对照者相比，ALS患者的发音变异性显著更高。实验2显示时长存在显著主效应（TT, p = .015; LL, p [原文此处存在内容截断]）。
### 研究结论
发音稳定性受言语信号时长的影响，且该效应在健康讲话者与ALS患者中表现一致。由于运动灵活性更强，舌尖稳定性可能受音位内容的显著影响。与健康对照者相比，ALS患者的发音变异性显著升高，这大概率反映了其言语运动控制的偏差。
### 补充材料
S1：针对所有发音部位的两因素混合方差分析结果，包含时长（2、3、5、8音节）与组别（健康对照、轻度ALS、重度ALS）的主效应及交互效应。统计分析基于原始数据，具有统计学显著性的结果以粗体标注。
S2：经Bonferroni校正的两两比较（Bonferroni corrected pairwise comparisons），用于评估STI均值差异及95%置信区间。统计分析基于原始数据，具有统计学显著性的差异以粗体标注。
S3：针对所有发音部位的两因素混合方差分析结果，包含片段时长（8音节短语的25%、50%、75%、100%）与组别（健康对照、轻度ALS、重度ALS）的主效应及交互效应。统计分析基于原始STI值，具有统计学显著性的结果以粗体标注。
S4：经Bonferroni校正的两两比较，用于评估STI值的均值差异，给出各发音部位的均值差。统计分析基于原始STI值，具有统计学显著性的差异以粗体标注。
### 文献引用
Teplansky, K. J., Wisler, A., Goffman, L., & Wang, J. (2024). 言语刺激时长对肌萎缩侧索硬化症患者舌部与唇部运动模式稳定性的影响. 《言语、语言与听力研究期刊》(Journal of Speech, Language, and Hearing Research), 67(10S), 4002–4014. https://doi.org/10.1044/2023_JSLHR-23-00079
### 出版者注
本文属于特刊“第8届国际言语运动控制国际会议精选论文”专栏。