Impact of Deafness and Language Experience on Visual Development

 描述(申请人提供)：虽然许多研究表明聋人的视力会改变和/或增强，但还不知道这是如何发展的。目前的建议是第一次研究聋人从婴儿期到成年期的视觉发育，以及18个月后接受人工耳蜗植入(CI)的听力恢复(HR)儿童，这一队列正在日益增加。在目标1中，我们使用不同年龄的可比刺激/范式，测量了聋儿和听力婴儿(6-10个月)、儿童(6-10岁)和成年人的不同视觉能力(包括运动、形状、面部和物体知觉)。许多聋人使用一种视觉语言，美国手语(ASL)，因此为了梳理聋人手语者的视觉变化是由于耳聋还是由于ASL经验，我们测试了第三组听力手语者，他们出生于聋人手语父母，具有与同样很早学习ASL的聋人大致相同的ASL经验。在婴儿中，我们测试了这三个相似的组(手势暴露的聋儿、非手势暴露的听力婴儿和手势暴露的听力婴儿)，以及另外一个对照组，即没有手势暴露的聋儿。为了进一步测试ASL的效果，我们询问视力改变的程度是否与 具有接受性的ASL熟练程度，通过标准化的ASL测试来衡量。通过了解耳聋和ASL引起的视力改变的发展轨迹，我们希望能阐明发育可塑性的机制。目的2通过研究HR儿童是否持续视力改变，探讨耳聋对视觉知觉的影响是否存在早期临界期。我们还测量了HR儿童的接受性口语熟练程度，这使我们能够问，在发育过程中，听觉输入必须在什么时候恢复，听觉和语言处理才能正常发育。这一目的也解决了CI领域日益关注的一个问题，即聋人的早期视力改变可能会阻碍CI的疗效。在这里，想法是 如果耳聋导致听觉皮质的功能重新分配用于视觉处理，这可能会阻止听觉皮质受到顺式刺激的适当刺激。如果这是真的，我们预计 研究发现，视力变化最大的人力资源人员在接受性口语方面的熟练程度会更差。目前的建议将是第一次在发育早期测试这一“适应不良假说”，结果将对优化CI儿童的最佳长期语言结果产生影响。

 DESCRIPTION (provided by applicant): While many studies have shown that vision is altered and/or enhanced in deaf people, it is not known how this develops. The current proposal is the first to study visual development in deaf people from infancy to adulthood, as well as in hearing restored (HR) children who received cochlear implants (CIs) by 18 months, a cohort that is increasingly on the rise. In Aim 1, we measure different visual abilities (including motion, form, face and object perception) in deaf and hearing infants (6 - 10 months), children (6 - 10 years) and adults, using comparable stimuli/paradigms across ages. Many deaf people use a visual language, American Sign Language (ASL), and thus to tease apart whether altered vision in deaf signers is due to deafness or to experience with ASL, we test a third control group of hearing signers, who were born to deaf signing parents and have roughly the same ASL experience as deaf people who also learned ASL early. In infants, we test these same three analogous groups (sign-exposed deaf infants, non-sign-exposed hearing infants, and sign-exposed hearing infants), as well as an additional control group, i.e., non-sign-exposed deaf infants. To test the effects of ASL further, we ask whether the degree of altered vision correlates with receptive ASL proficiency, as measured with standardized ASL tests. By understanding the developmental trajectory of altered vision due to deafness vs. ASL, we hope to elucidate mechanisms of developmental plasticity. Aim 2 asks whether there is an early critical period for the effects of deafness on visual perception, by investigating whether altered vision persists in HR children. We also measure receptive spoken language proficiency in HR children, which allows us to ask by when in development must auditory input be restored for auditory and speech processing to develop normally. This aim also addresses a growing concern in the CI field that altered early vision in deaf people may hinder the efficacy of the CI. Here, the idea is that if deafness leads to functional reallocation of auditory cortex for visual processing, this might prevent the auditory cortex from being properly stimulated by CIs. If this is true, we expect to find that HR individuals with the most altered vision will show the worse proficiency in receptive spoken language. The current proposal will be the first to test this "maladaptive hypothesis" early in development, and the results should have implications for optimizing best long-term language outcomes in CI children.