Visual Speech Perception and Neural Processing

描述（申请人提供）：视觉语言的感知（唇读/言语阅读）可以足以获得第一语言和进行日常交流。在嘈杂的环境下，听力损失的人可能需要依靠唇读，即使他们有感觉辅助设备（助听器，人工耳蜗）。唇读在语前重度听力障碍（聋人）个体中表现出可塑性，因此，聋人成人的唇读准确率往往远远超过正常听力成人的唇读准确率。本项目的长期研究目标是从感觉和知觉过程以及潜在的神经机制方面解释耳聋专家、听力正常个体和特发性突发性深度听力损失个体的唇读。临床的长期目标是开发有效的唇读训练和评估工具。在研究1中，我们假设聋成人读唇者在视觉空间频率处理相关的低感觉约束水平上比正常听力的成年人更有能力。该研究应用了一种利用对比度阈值估计视觉临界空间频带的方法。在研究2中，我们假设更快和更敏感的视觉语音刺激知觉加工是专家读唇者优势的主要组成部分。采用快速判别方法研究视觉语音的知觉敏感性和长期记忆结构。在研究3中，同样的假设将被测试，但刺激将由一个新的视觉语音合成器产生。在研究4中，假设专家读唇与语音外源性和可能的神经可塑性皮层效应有关。电生理事件相关电位（ERPs）是在目标识别任务中获得的。语言前失聪的读唇专家将与正常听力的成年人进行比较，以分离专家读唇优势的来源。将招募突发性听力损失患者来研究输入刺激突然变化后可能迅速发生的感知和神经可塑性效应。与公共卫生的相关性：设计实验的目的是导致更有效的唇读评估和训练，这将与在嘈杂条件下涉及听力损失和感知退化的广泛情况有关。视觉语音合成器的应用包括基于计算机的听力障碍儿童语音感知训练系统。关于成人学习和可塑性的知识很重要，因为听力损失是与衰老相关的常见现象。

DESCRIPTION (provided by applicant): Perception of visible speech (lipreading/speechreading) can be sufficient for acquiring a first language and carrying out everyday communication. Under noisy conditions, individuals with hearing loss may need to rely on lipreading, even if they have sensory aids (hearing aids, cochlear implants). Lipreading demonstrates plasticity in individuals with prelingual profound hearing impairments (deaf), such that accuracy in deaf adults frequently far exceeds accuracy in normal-hearing adults. The long-term research aim of this proposed project is to explain, in terms of sensory and perceptual processes and underlying neural mechanisms, lipreading in deaf experts, in individuals with normal hearing, and in individuals with idiopathic sudden profound hearing loss. The long-term clinical aim is to develop effective tools for lipreading training and assessment. In Study 1, it is hypothesized that expert deaf adult lipreaders are more capable at the level of lower-sensory constraints related to visual spatial frequency processing than are normal-hearing adults. The study applies a method for estimating visual critical spatial frequency bands using contrast thresholds. In Study 2, it is hypothesized that faster and more sensitive perceptual processing of the visual phonetic stimulus is a major component of the expert lipreader's advantage. A speeded discrimination method will be used to study perceptual sensitivity and longterm memory structure for visual phonetic speech. In Study 3, the same hypothesis will be tested, but the stimuli will be generated with a new visual speech synthesizer. In Study 4, the hypothesis is that expert lipreading is associated with phonetic exogenous and possibly neuroplastic cortical effects. Electrophysiological event related potentials (ERPs) will be obtained during a target discrimination task. Prelingually deaf adults who are expert lipreaders will be compared with normal- hearing adults to isolate sources of the expert's lipreading advantage. Patients with sudden hearing loss will be recruited to study perceptual and neuroplastic effects that may occur rapidly following an abrupt change in input stimulation. Relevance to public health: Experiments are designed to lead to more effective lipreading assessment and training, which would be relevant to a wide range of conditions involving hearing loss and degraded perception under noisy conditions. Applications of the visual speech synthesizer include computer-based training systems for speech perception in children with hearing impairments. Knowledge about learning and plasticity in adults is important, as hearing loss is a frequent occurrence associated with aging.