Department of Speech-Language-Hearing: Sciences & Disorders, The University of Kansas, Lawrence.
Am J Speech Lang Pathol. 2022 Sep 7;31(5):2022-2044. doi: 10.1044/2022_AJSLP-22-00046. Epub 2022 Aug 16.
The aim of this study is to identify the articulatory underpinnings of the acoustic-phonetic correlates of functional speech decline in individuals with amyotrophic lateral sclerosis (ALS).
Thirteen individuals with varying severities of speech impairment secondary to ALS and 10 neurologically healthy controls speakers read 12 minimal word pairs, targeting the contrasts in the height, advancement, and length of vowels; the manner and place of articulation for consonants and consonant cluster; and liquid and glide approximants, 5 times. Sixteen acoustic features were extracted to characterize the phonetic contrasts of these minimal word pairs. These acoustic features were correlated with a functional speech index-intelligible speaking rate-using penalized regression, based on which the contributive features were identified as the acoustic-phonetic correlates of the functional speech outcome. Articulatory contrasts of the minimal word pairs were characterized by a set of dissimilarity indices derived by the dynamic time warping algorithm, which measured the differences in the displacement and velocity trajectories of tongue tip, tongue dorsum, lower lip, and jaw between the minimal word pairs. The contributive articulatory features to the acoustic-phonetic correlates were identified by penalized regression.
A variety of acoustic-phonetic features were identified as contributing to the functional speech outcome, of which the contrasts in vowel height and advancement, [r]-[l], [r]-[w], and initial cluster-singleton were the most affected in individuals with ALS. Differential articulatory underpinnings were identified for these acoustic-phonetic features. Impairments of these articulatory underpinnings, especially of tongue tip and tongue dorsum velocities and tongue tip displacement, were associated with reduced acoustic-phonetic contrasts of the minimal word pairs, in a context-specific manner.
The findings established explanatory relationships between articulatory impairment and the acoustic-phonetic profile of functional speech decline in ALS, providing useful information for developing targeted management strategies to improve and prolong functional speech in individuals with ALS.
本研究旨在确定肌萎缩侧索硬化症（ALS）患者功能言语下降的声学-语音相关性的发音基础。
13 名因 ALS 导致不同程度言语障碍的患者和 10 名神经健康对照者朗读 12 对最小词对 5 次，这些最小词对针对元音高度、前伸和长度、辅音和辅音群的发音方式和发音部位以及流音和滑音的对比。提取 16 个声学特征来描述这些最小词对的语音对比。使用惩罚回归，基于这些声学特征与功能言语指标（可理解的说话率）进行相关，确定功能言语结果的声学语音相关因素。通过动态时间 warping 算法得出一组最小词对发音差异的不相似度指数，该算法测量了最小词对之间舌尖、舌背、下唇和下颌的位移和速度轨迹的差异。通过惩罚回归确定对声学语音相关性有贡献的发音特征。
确定了多种声学语音特征作为功能言语结果的贡献因素，其中元音高度和前伸度、[r]-[l]、[r]-[w]以及起始辅音群-单元音的对比在 ALS 患者中受影响最大。确定了这些声学语音特征的不同发音基础。这些发音基础的损伤，特别是舌尖和舌背的速度和舌尖的位移，与最小词对的声学语音对比减少有关，且具有特定语境下的相关性。
这些发现确立了发音障碍与 ALS 患者功能言语下降的声学语音特征之间的解释性关系，为制定有针对性的管理策略提供了有用信息，以改善和延长 ALS 患者的功能言语。
