EFFECTS OF ASYMMETRIC HEARING IN ACOUSTIC LISTENERS AND COCHLEAR IMPLANT USERS

描述(由申请人提供)：我们研究的目标是了解成人和儿童非对称性听力损失的影响。例如，当一只耳朵听力严重受损，而另一只耳朵听力正常时，就会发生听力不对称。或者，当一只耳朵严重失聪，但较好的一只耳朵有部分听力。在任何一种情况下，不平衡的投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。在目标1中，我们确定了影响成人和儿童单侧听力损失观察结果的变异性来源。了解这种变异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、相关的人口统计学和性能测量来评估在噪声和本地化中预测语音识别的因素。在目标2中，我们评估了在单侧听力损失的噪声中理解语音的缺陷会影响非听觉认知脑区的加工的假说。我们提出了一种在存在和不存在多个说话者喋喋不休的情况下，由高可预测性句子和低可预测性句子引起的活动的功能成像研究。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在噪声中对言语理解能力下降的补偿涉及到更大的认知中心激活，包括颞顶叶、额叶下部和背外侧，以及扣带皮质。在目标3中，我们研究了人工耳蜗植入对患有不对称性听力损失的成人和儿童的益处，这些成人和儿童的耳聋发病年龄不同，听力较差的人有听力病史。我们预测，即使一只耳朵有部分听力，大脑已经学会了用相当好的声学信号来听，较差的耳朵开始耳聋的年龄将与预后相关。在目标4中，我们确定了双侧人工耳蜗植入者中导致双耳之间语音识别不对称和双侧表现下降的因素。在语言前期失聪的儿童中，我们预计手术之间的时间越长，耳朵之间的语音识别不对称越大，两侧的表现也就越差。在语后成人中，我们预测，耳蜗间电极放置的更大差异与耳朵之间语音识别的更大不对称性、两侧表现的降低以及耳朵间音调感知的更大差异相关。综上所述，拟议的研究计划将探索单侧听力损失的行为变异和脑重组的基础。研究结果将确定听力不对称如何影响行为结果，以及是否存在单侧耳聋早期发病的新考虑因素。在患有非对称性听力损失的儿童和成人中，所获得的知识可能会影响关于治疗耳朵、治疗类型和治疗时间的决定。最后，结果将加强对耳蜗间电极放置效应的理解，并潜在地影响双侧植入物接受者的治疗决定。

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.