Jacks Adam
Department of Communication Disorders, Texas State University, San Marcos, TX 78666, USA.
J Speech Lang Hear Res. 2008 Aug;51(4):898-913. doi: 10.1044/1092-4388(2008/066).
This study explored vowel production and adaptation to articulatory constraints in adults with acquired apraxia of speech (AOS) plus aphasia.
Five adults with acquired AOS plus aphasia and 5 healthy control participants produced the vowels [i], [epsilon], and [ae] in four word-length conditions in unconstrained and bite block conditions. In addition to acoustic and perceptual measures of vowel productions, individually determined idealized vowels based on each participant's best performance were used to assess vowel accuracy and distinctiveness.
Findings showed (a) clear separation of vowel formants in speakers with AOS; (b) impaired vowel production in speakers with AOS, shown by perceptual measures of vowel quality and acoustic measures of vowel accuracy and contrastivity; and (c) incomplete compensation to bite block compensation both for individuals with AOS and for healthy controls.
Although adults with AOS were less accurate overall in vowel production than unimpaired speakers, introduction of a bite block resulted in similar patterns of decreased vowel accuracy for the two groups. Findings suggest that feedback control for vowel production is relatively intact in these individuals with AOS and aphasia. Predominant use of feedback control mechanisms is hypothesized to account for characteristic vowel deficits of the disorder.
本研究探讨了获得性言语失用症（AOS）合并失语症的成年人的元音发音以及对发音限制的适应性。
5名患有获得性AOS合并失语症的成年人和5名健康对照参与者在无限制和咬块条件下的四种词长条件下发出元音[i]、[ε]和[æ]。除了对元音发音进行声学和感知测量外，还使用基于每个参与者最佳表现单独确定的理想化元音来评估元音的准确性和独特性。
研究结果表明：（a）患有AOS的说话者的元音共振峰明显分离；（b）患有AOS的说话者的元音发音受损，这通过元音质量的感知测量以及元音准确性和对比度的声学测量得以体现；（c）患有AOS的个体和健康对照者对咬块补偿均存在不完全补偿。
尽管患有AOS的成年人在元音发音方面总体上不如未受损的说话者准确，但引入咬块后，两组的元音准确性下降模式相似。研究结果表明，这些患有AOS和失语症的个体在元音发音的反馈控制方面相对完整。据推测，反馈控制机制的主要使用是该疾病特征性元音缺陷的原因。
