Determinants of Cross Modal Plasticity in Children with Cochlear Implants

 描述（由申请人提供）：先天性耳聋导致儿童获得口语的明显语言延迟。语言知识贫乏的级联效应影响了广泛的心理和认知行为，包括自我调节、工作记忆和阅读。耳蜗植入（CI）是聋儿的一种流行治疗选择。这些设备将电刺激传递到听觉神经，绕过发生故障的外围听觉机制。在生命早期接受人工耳蜗植入并进行强化口腔/听觉治疗的聋儿通常在口语习得方面取得很大进步。然而，尽管临床医生尽了最大的努力，即使在最佳条件下，语言结果也存在很大的差异。人们对造成这种不成功的因素的相互作用知之甚少。一个越来越多的关注是，在耳聋的条件下，听觉系统可能会受到适应不良的跨模态可塑性（CMP）。在跨通道可塑性中，一个完整的感觉系统（如视觉）的处理需求可能会招募新生的听觉皮层，使其不太适合语音处理。耳聋的动物模型已经显示出功能上显著的跨模态可塑性的证据，其视觉处理与听觉皮层激活有关。对聋人手语成年人的研究也报告了跨模态可塑性的证据，包括初级听觉皮层内的视觉反应。视觉手语处理的左半球听觉区域的专门化证明了颞叶皮层网络的可塑性。然而，我们的知识存在重大差距。CMP的沉淀条件和CMP的发展时间过程尚不清楚。有一个迫切需要的研究，同时评估听觉和视觉处理的聋儿与人工耳蜗植入在语言发展的形成阶段。也不知道如何沟通方式（签署或语音）影响跨模态可塑性。我们使用电生理学获得听觉和视觉诱发电位，并评估功能的完整性和发展的听觉皮层和存在的跨模态的变化，在语前聋儿童谁接受人工耳蜗植入。使用创新的行为测试和语言功能的标准化措施，我们将评估口语和手语经验的跨模态可塑性表达的影响。这些研究将有助于我们更好地理解CMP的决定因素及其与语言使用的关系。研究结果将对聋儿的临床实践产生重大影响。

 DESCRIPTION (provided by applicant): Congenital deafness leads to significant language delays in children acquiring spoken language. Cascading effects of impoverished linguistic knowledge impact a wide range of psychological and cognitive behaviors including self-regulation, working memory, and reading. Cochlear implants (CIs) are a popular treatment option for deaf children. These devices deliver electrical stimulation to the auditory nerve, bypassing malfunctioning peripheral auditory mechanisms. Deaf children who receive cochlear implants early in life and engage in intensive oral/aural therapy often make great strides in spoken language acquisition. However, despite clinicians' best efforts, even under optimal conditions, there is a great deal of variability in language outcomes. The interplay of factors contributing to this lack of success is poorly understood. One mounting concern is that under conditions of deafness, the auditory system may be subject to maladaptive cross-modal plasticity (CMP). In cross-modal plasticity the processing demands of an intact sensory system, such as vision, may recruit nascent auditory cortex making it less available for speech processing. Animal models of deafness have shown evidence of functionally significant cross-modal plasticity with enhancements in visual processing tied to auditory cortical activation. Studies of deaf signing adults have also reported evidence of cross-modal plasticity including visual responsiveness within primary auditory cortex. The specialization of left-hemisphere auditory regions for visual sign language processing attests to the malleability of temporal lobe cortical networks. However, there are significant gaps in our knowledge. The conditions that precipitate CMP and the developmental time course of CMP are not known. There is an urgent need for studies that simultaneously assess auditory and visual processing in deaf children with cochlear implants during the formative stages of language development. Nor is it known how communication modality (signed or speech) impacts cross-modal plasticity. We use electrophysiology to obtain auditory and visual evoked potentials and assess functional integrity and development of the auditory cortex and the presence of cross modal changes in prelingually deaf children who have received cochlear implant. Using innovative behavioral testing and standardized measures of language function we will assess the impact of spoken and signed language experience in the expression of cross-modal plasticity. The proposed studies will advance our understanding of the determinants of CMP and its relation to language use. The findings will have a significant impact on clinical practices for deaf children.