EFFECTS OF ASYMMETRIC HEARING IN ACOUSTIC LISTENERS AND COCHLEAR IMPLANT USERS

描述（由申请人提供）：我们的研究目的是了解成人和儿童不对称听力损失的影响。例如，当一只耳朵有严重的听力损失而另一只耳朵听力正常时，就会出现听力不对称。或者，当一只耳朵严重失聪，而另一只耳朵有部分听力。在任何一种情况下，不平衡的输入都会对日常生活中的交流产生不利影响，并产生其他负面后果。在Aim 1中，我们确定了影响单侧听力损失的成人和儿童结果的变异性来源。了解这种可变性可以改善患者的咨询和治疗选择。我们将通过调查认知能力、相关的人口统计数据和性能指标来评估预测噪声和本地化中的语音识别的因素。在目的2中，我们评估了单侧听力损失患者在噪音中理解语言的缺陷会影响非听觉认知脑区的加工的假设。我们提出了一项功能成像研究，在有和没有多语者牙牙学语的情况下，高可预测性和低可预测性句子所引起的活动。我们预测，与听力正常的成年人相比，单侧听力损失的成年人补偿噪音中言语理解能力的下降涉及到颞顶叶、下叶和背外侧额叶以及扣带皮层的认知中心的更大激活。在Aim 3中，我们研究了人工耳蜗植入对非对称听力损失的成人和儿童的益处，以及不同年龄的耳聋发病和较差耳朵的听力病史。我们预测，即使一只耳朵有部分听力，而大脑已经学会了用相当好的声音信号来听，在较差的一只耳朵中，耳聋的发病年龄将与结果有关。在Aim 4中，我们确定了双侧人工耳蜗受者导致双耳之间语音识别不对称和双侧表现下降的因素。在语言前失聪的儿童中，我们预计手术间隔时间越长，两耳之间的语音识别不对称越大，双耳的表现也越差。在语言后的成年人中，我们预测耳蜗之间电极放置的更大差异与两耳之间语音识别的更大不对称、双侧表现的降低以及音高感知的更大耳际差异相关。综上所述，本研究计划将探讨单侧听力损失的行为变异和大脑重组的基础。研究结果将决定听力不对称如何影响行为结果，以及是否存在早期单侧耳聋的新考虑。对于患有非对称听力损失的儿童和成人，所获得的知识可能会影响治疗耳部、治疗类型和治疗时机的决定。最后，研究结果将增强对耳蜗间电极放置效果的理解，并可能影响双侧植入者的治疗决策。

DESCRIPTION (provided by applicant): The goal of our research is to understand the effects of asymmetric hearing loss in adults and children. Hearing asymmetry occurs, for example, when one ear has profound hearing loss and the other ear has normal hearing. Or, when one ear is profoundly deaf but the better ear has partial hearing. In either case, the imbalanced inputs detrimentally affect communication in everyday life and have other negative consequences. In Aim 1, we identify the sources of variability contributing to outcomes observed in adults and children with unilateral hearing loss. Understanding this variability could improve counseling and treatment options for patients. We will evaluate factors that predict speech recognition in noise and localization by investigating cognitive abilities, associated demographics, and measures of performance. In Aim 2, we assess the hypothesis that deficits in comprehending speech in noise with unilateral hearing loss affect processing in non- auditory cognitive brain regions. We propose a functional imaging study of activity evoked by high and low predictability sentences in the presence and absence of multi-talker babble. We predict that compensating for degraded speech comprehension in noise involves greater activation of cognitive centers in temporo-parietal, inferior and dorsolateral frontal, and cingulate cortex in adults with unilateral hearing loss compared to those with normal hearing. In Aim 3, we examine the benefit of cochlear implantation for adults and children with asymmetric hearing loss and varied ages at onset of deafness and hearing histories in the poorer ear. We predict that even if one ear has partial hearing and the brain has learned to hear with a fairly good acoustic signal, age at onset of deafness in the poorer ear will be associated with outcome. In Aim 4, we identify factors in bilateral cochlear implant recipients that contribute to asymmetry in speech recognition between ears and reduced bilateral performance. In prelingually deaf children, we expect that a longer time between surgeries corresponds to larger asymmetries in speech recognition between ears and reduced bilateral performance. In postlingual adults, we predict that greater divergence in electrode placement between cochleas correlates with larger asymmetries in speech recognition between ears, reduced bilateral performance, and larger interaural differences in pitch percepts. To summarize, the proposed research program will probe the basis of behavioral variability and brain reorganization in unilateral hearing loss. Findings will determine how asymmetry in hearing affects behavioral outcomes and whether new considerations exist for early onset of unilateral deafness. Knowledge gained could influence decisions about treated ear, treatment types, and timing of treatment in children and adults with asymmetric hearing loss. Finally, results will enhance understanding of inter-cochlea electrode placement effects and potentially influence treatment decisions for bilateral implant recipients.