Effects of Hearing Status on Adult Speech Production

本应用程序的目标是：为听力在言语产生中的作用的知识体系做出贡献；描述听障人士的言语及义肢的效果；并评估和完善听力在言语中的作用模型的特性。为了实现这些目标，我们对成年人工耳蜗使用者进行了实验；助听器使用者；不使用假肢的聋哑人；以及听力正常的讲话者。根据我们的听力在成人言语运动控制中的作用模型，言语产生涉及到听觉目标，因此在发音运动和它们的听觉结果之间存在映射。本项目主要研究：(1)长期失聪后映射关系的退化、部分听力恢复后映射关系的恢复以及短期听力变化对映射关系的影响；(2)在有听力和无听力的情况下使用咬合块对言语的影响；(3)有证据表明，植入人工耳蜗后，语音变异对听觉目标的映射有所改善；(4)义肢使用者的语音类别结构；(5)增加听觉目标数量对听觉反馈变化的影响（通过比较两种不同元音清单的语言）；(6)清晰要求和听觉反馈对语音对比的影响；(7)语音参数随听力变化而变化的时机；(8)听力状况对口语音节视听整合的影响；(9)听力损失对视觉言语激活听觉皮层的影响；（10）失聪年龄对言语皮层激活的影响；（11）失聪年龄对语音对比的影响。在大多数研究中使用的独立变量是：初始提供人工耳蜗；听觉反馈修正；以及进行修饰的阶段（植入前，植入后不久，植入后很久）。一般来说，这些干预措施的效果是通过检查音素识别、皮层激活水平和语音产生中选择的语音对比（辅音和元音）的声学测量以及整个元音空间的声学特性来评估的。

The goals of this application are: to contribute to the body of knowledge on the role of hearing in speech production; to describe the speech of hearing-impaired persons and the effects of prostheses; and to evaluate and refine the properties of a model of the role of hearing in speech. We pursue those goals by conducting experiments with: adult cochlear implant users; hearing aid users; deaf speakers who do not use prostheses; and speakers with normal hearing. According to our model of the role of hearing in adult speech motor control, speech production involves auditory goals and thus mappings between articulatory movements and their auditory consequences. The project investigates: (1) how mappings are degraded after long deafness, retuned when some hearing is restored, and affected by short-term changes in hearing; (2) the effects on speech when bite blocks are introduced with and without hearing; (3) evidence that the mapping of allophonic variation into auditory goals improves after the speaker receives a cochlear prosthesis; (4) the structure of phonetic categories in prosthesis users; (5) the effects of increasing the number of auditory goals (by comparing two languages with different vowel inventories) on responses to changes in auditory feedback; (6) the effects of clarity demands and auditory feedback on phonetic contrasts; (7) the timing of changes in speech parameters in response to changes in hearing; (8) effects of hearing status on audio-visual integration of spoken syllables; (9) effects of hearing loss on activation of auditory cortex by visible speech; (10) effects of age at hearing loss on cortical activation during speech; and (11) the effects of age at hearing loss on phonetic contrasts. Independent variables that are employed in most of the studies are: initial provision of a cochlear implant; modification of auditory feedback; and the stage at which the modification is made (before implantation, shortly after, long after). In general, the effects of these interventions are assessed by examining phoneme recognition, levels of cortical activation and, in speech production, acoustic measures of selected phonetic contrasts - consonantal and vocalic - as well as properties of the overall acoustic vowel space.