Litovsky Ruth Y, Gordon Karen
University of Wisconsin-Madison, 1500 Highland Ave, Madison, WI, 53705, United States.
University of Toronto, Canada.
Hear Res. 2016 Aug;338:76-87. doi: 10.1016/j.heares.2016.01.003. Epub 2016 Jan 30.
Spatial hearing skills are essential for children as they grow, learn and play. These skills provide critical cues for determining the locations of sources in the environment, and enable segregation of important sounds, such as speech, from background maskers or interferers. Spatial hearing depends on availability of monaural cues and binaural cues. The latter result from integration of inputs arriving at the two ears from sounds that vary in location. The binaural system has exquisite mechanisms for capturing differences between the ears in both time of arrival and intensity. The major cues that are thus referred to as being vital for binaural hearing are: interaural differences in time (ITDs) and interaural differences in levels (ILDs). In children with normal hearing (NH), spatial hearing abilities are fairly well developed by age 4-5 years. In contrast, most children who are deaf and hear through cochlear implants (CIs) do not have an opportunity to experience normal, binaural acoustic hearing early in life. These children may function by having to utilize auditory cues that are degraded with regard to numerous stimulus features. In recent years there has been a notable increase in the number of children receiving bilateral CIs, and evidence suggests that while having two CIs helps them function better than when listening through a single CI, these children generally perform worse than their NH peers. This paper reviews some of the recent work on bilaterally implanted children. The focus is on measures of spatial hearing, including sound localization, release from masking for speech understanding in noise and binaural sensitivity using research processors. Data from behavioral and electrophysiological studies are included, with a focus on the recent work of the authors and their collaborators. The effects of auditory plasticity and deprivation on the emergence of binaural and spatial hearing are discussed along with evidence for reorganized processing from both behavioral and electrophysiological studies. The consequences of both unilateral and bilateral auditory deprivation during development suggest that the relevant set of issues is highly complex with regard to successes and the limitations experienced by children receiving bilateral cochlear implants. This article is part of a Special Issue entitled <Annual Reviews 2016>.
空间听觉技能对儿童的成长、学习和玩耍至关重要。这些技能为确定环境中声源的位置提供关键线索，并能将重要声音（如语音）与背景掩蔽声或干扰声区分开来。空间听觉取决于单耳线索和双耳线索的可用性。后者源于来自不同位置声音到达双耳的输入信号的整合。双耳系统具有精妙的机制来捕捉双耳在到达时间和强度上的差异。因此，被认为对双耳听觉至关重要的主要线索是：耳间时间差（ITD）和耳间声级差（ILD）。在听力正常（NH）的儿童中，空间听觉能力在4 - 5岁时已相当发达。相比之下，大多数失聪并通过人工耳蜗（CI）聆听的儿童在生命早期没有机会体验正常的双耳听觉。这些儿童可能不得不利用在许多刺激特征方面退化的听觉线索来发挥功能。近年来，接受双侧人工耳蜗植入的儿童数量显著增加，证据表明，虽然拥有两个人工耳蜗比通过单个人工耳蜗聆听能让他们功能更好，但这些儿童的总体表现仍比听力正常的同龄人差。本文回顾了一些关于双侧植入儿童的近期研究工作。重点是空间听觉的测量，包括声音定位、在噪声中言语理解的掩蔽解除以及使用研究处理器的双耳敏感性。纳入了行为学和电生理学研究的数据，重点是作者及其合作者的近期工作。讨论了听觉可塑性和剥夺对双耳及空间听觉出现的影响，以及行为学和电生理学研究中重组处理的证据。发育过程中单侧和双侧听觉剥夺的后果表明，对于接受双侧人工耳蜗植入的儿童所取得的成功和遇到的局限性而言，相关问题集非常复杂。本文是名为《2016年年度回顾》特刊的一部分。
