Feedforward and feedback control in apraxia of speech: effects of noise masking on vowel production.
Feedforward and feedback control in apraxia of speech: effects of noise masking on vowel production.
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DOI：
10.1044/2014_jslhr-s-13-0300
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发表时间：
2015-04
期刊：
影响因子：
--
通讯作者：
Guenther FH
中科院分区：
文献类型：
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作者：
Maas E;Mailend ML;Guenther FH
本研究旨在检验由DIVA模型导出的两个关于言语失用症（AOS）的假设：（1）前馈系统缺陷假设和（2）反馈系统缺陷假设。我们使用噪声掩蔽来最大限度地减少语音过程中的听觉反馈。六个扬声器与AOS和失语症，四个失语症没有AOS，和两个未受损的扬声器组（年轻人和老年人）参加。声学措施元音对比度，变异性和持续时间进行了分析。年轻的，但不是老年人未受损的扬声器显着降低元音对比度与噪声掩蔽。相对于年龄较大的对照组，AOS组的元音持续时间更长，并且在掩蔽条件下元音对比度下降幅度更大。变异性无显著差异。六位AOS患者中有三位表现出群体模式。无AOS的失语症患者在对比度、持续时间或变异性方面与对照组无差异。AOS组与掩蔽噪声的元音对比度的较大降低与前馈系统缺陷假设一致，但与反馈系统缺陷假设不一致;然而，影响很小，并不存在于所有AOS个体扬声器中。这些研究结果的理论影响和替代解释进行了讨论。
This study was designed to test two hypotheses about apraxia of speech (AOS) derived from the DIVA model: (1) the Feedforward System Deficit Hypothesis and (2) the Feedback System Deficit Hypothesis. We used noise masking to minimize auditory feedback during speech. Six speakers with AOS and aphasia, four with aphasia without AOS, and two unimpaired speaker groups (younger and older adults) participated. Acoustic measures of vowel contrast, variability, and duration were analyzed. Younger, but not older unimpaired speakers showed significantly reduced vowel contrast with noise masking. Relative to older controls, the AOS group showed longer vowel durations, and a greater reduction in vowel contrast under masking conditions. There were no significant differences in variability. Three of the six speakers with AOS demonstrated the group pattern. Speakers with aphasia without AOS did not differ from controls in contrast, duration, or variability. The greater reduction in vowel contrast with masking noise for the AOS group is consistent with the Feedforward System Deficit Hypothesis but not with the Feedback System Deficit Hypothesis; however, effects were small and not present in all individual speakers with AOS. Theoretical implications and alternative interpretations of these findings are discussed.