Impact of Deafness and Language Experience on Visual Development

 描述（由申请人提供）：虽然许多研究表明聋人的视力会改变和/或增强，但尚不清楚这是如何发展的。目前的提案是第一个研究聋人从婴儿期到成年期的视觉发育，以及在18个月前接受人工耳蜗植入（CI）的听力恢复（HR）儿童中，这一群体越来越多。在目标1中，我们使用不同年龄段的可比刺激/范例，测量聋哑婴儿（6 - 10个月）、儿童（6 - 10岁）和成人的不同视觉能力（包括运动、形状、面部和物体感知）。许多聋人使用一种视觉语言，美国手语（ASL），因此，为了区分聋人手语者的视力改变是由于耳聋还是由于ASL的经验，我们测试了第三个听力手语者的对照组，他们出生于聋人手语父母，与早期学习ASL的聋人有大致相同的ASL经验。在婴儿中，我们测试了这三个类似的组（符号暴露的聋哑婴儿，非符号暴露的听力婴儿和符号暴露的听力婴儿），以及一个额外的对照组，即，没有接触过手语的聋哑婴儿为了进一步测试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熟练度，如标准化ASL测试所测量的。通过了解耳聋与ASL导致的视力改变的发展轨迹，我们希望阐明发育可塑性的机制。目的2通过调查HR儿童的视力改变是否持续，探讨耳聋对视觉感知的影响是否存在早期关键期。我们还测量了HR儿童的接受性口语能力，这使我们能够询问在发育过程中何时必须恢复听觉输入以使听觉和言语处理正常发展。这一目标也解决了CI领域日益增长的担忧，即聋人早期视力的改变可能会阻碍CI的疗效。在这里， 如果耳聋导致听觉皮层的功能重新分配用于视觉处理，这可能会阻止听觉皮层受到CI的适当刺激。如果这是真的， 发现视力改变最严重的HR个体在接受性口语中表现出更差的熟练程度。目前的建议将是第一个测试这种“适应不良的假设”在发展的早期，结果应该有优化CI儿童的最佳长期语言结果的影响。

 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.