Determinants of Cross Modal Plasticity in Children with Cochlear Implants

 描述(申请人提供)：先天性耳聋导致儿童在获得口语时出现明显的语言延迟。贫乏的语言知识的连锁效应影响了包括自我调节、工作记忆和阅读在内的广泛的心理和认知行为。人工耳蜗(CI)是耳聋儿童的一种流行的治疗选择。这些设备绕过故障的外周听觉机制，向听神经提供电刺激。耳聋儿童在生命早期接受人工耳蜗植入，并进行强化的口头/听觉治疗，通常会在口语习得方面取得很大进展。然而，尽管临床医生尽了最大努力，即使在最佳条件下，语言结果也存在很大的差异性。人们对导致这种缺乏成功的因素之间的相互作用知之甚少。一个日益令人担忧的问题是，在耳聋的条件下，听觉系统可能会受到不适应的跨模式可塑性(CMP)的影响。在跨模式可塑性中，一个完整的感觉系统的处理需求，如视觉，可能会招募新生的听觉皮质，使其更少地用于语音处理。耳聋的动物模型已经显示出功能上显着的跨模式可塑性，视觉处理的增强与听觉皮质的激活有关。对聋人手语成人的研究也报告了跨模式可塑性的证据，包括初级听觉皮质内的视觉反应。视觉手语处理的左半球听觉区域的专门化证明了颞叶皮质网络的可塑性。然而，我们的知识有很大的差距。化学机械抛光的形成条件以及化学机械抛光的发展时间尚不清楚。在语言发育的形成阶段，迫切需要研究同时评估植入人工耳蜗术的聋儿的听觉和视觉加工。也不知道沟通方式(手语或言语)如何影响跨通道可塑性。我们使用电生理学来获得听觉和视觉诱发电位，并评估接受人工耳蜗术的语前聋儿童的听觉皮质的功能完整性和发育，以及是否存在交叉模式的变化。使用创新的行为测试和标准化的语言功能测量，我们将评估口语和手语体验在跨通道可塑性表达中的影响。这些研究将有助于我们更好地理解语言习得的决定因素及其与语言使用的关系。这一发现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.