Localization and Speech Intelligibility in EAS and Bilateral CI Users

描述(申请人提供)：直到最近，大多数人工耳蜗术都是单侧的。然而，现在有两组植入患者可以使用来自两只耳朵的相同类型的输入。一组使用双侧人工耳蜗术(CI)。这些人有两个无残留听力的CI(双侧CI)。另一组保留了植入耳的低频声学听力，对侧耳也有声学低频听力。这些患者在植入的耳朵中结合了电和声刺激(EAS)，并对侧有残余的低频听力。他们可以获得双边低频声学提示，并被称为EAS。(EAS不同于双峰CI患者，后者通过CI在一只耳朵进行电刺激，而在CI的对侧进行听觉听力。换句话说，双峰CI用户的每只耳朵具有不同的听力。)我们可以使用这两组患者，双侧CI和EAS，具有不同类型的双侧听力来评估耳间水平差(ILD)线索和耳间时间差(ITD)线索在现实世界环境中定位和语音理解中的价值。耳间时间和强度的差异为正常听者提供了定位的能力，并被认为是空间掩蔽释放(SRM)的基础。到目前为止，只有一篇关于EAS用户本地化的论文(Dunn等人，2010年)。邓恩报告说，EAS用户能够本地化，尽管没有正常听力听众那么好。然而，这项研究缺乏对本地化所使用的频率信息的控制。人们一致认为，双边用户对ILD具有敏感性，但无法获得ITD线索(Grantham等人，2007年)。Loizou等人。(2009)报告说，双边CI用户没有从屏蔽的空间释放中受益，这可能是由于缺乏ITD线索。如果ITD线索对于现实世界噪声环境中的SRM是必要的，那么EAS患者在这些环境中可能比双侧CI患者受益更多。本研究的具体目的是确定(I)ITD、ILD或两者中的哪一种潜在机制是两组本地化的基础；(Ii)当CI听者处于困难的真实世界听力情境中时，ITD和ILD线索中的哪一个提供了更大的优势；以及(Iii)耳间ITD和ILD线索的可用性与SRM之间是否存在关系。对这些问题的回答将塑造我们对人工耳蜗术益处的理解，并向患者提供有关顺式人工耳机的现实世界益处的信息。研究设计为2(组=双侧CI和EAS)×3(低通、高通、宽带噪声)重复测量方差分析用于三种噪声条件下的定位能力，a 2(组=双侧CI和EAS)×2(听力和噪声条件)重复测量ANOVA用于噪声中的言语感知。将计算一项分析，以确定本地化性能是否与空间掩蔽释放相关。 与公共健康相关：对于试图在双边或EAS之间做出选择的潜在人工耳蜗患者来说，这一影响可能会合理地影响患者、外科医生、听力科医生、纳税人，甚至保险公司的决定。这些信息将为潜在的CI用户和听力保健提供者提供必要的信息，以做出关于预期结果的知情决定。

DESCRIPTION (provided by applicant): Until relatively recently, most cochlear implants were unilateral. Now, however, there are two groups of implant patients who can use the same kind of input from two ears. One group uses bilateral cochlear implants (CI). These individuals have two CIs with no residual hearing (Bilateral CI). Another group has preserved low- frequency acoustic hearing in the implanted ear and also has acoustic low-frequency hearing in the contralateral ear. These patients combine electric and acoustic stimulation (EAS) in the implanted ear and have residual low frequency hearing contralaterally. They have access to bilateral low frequency acoustic cues and are referred to as EAS. (EAS are different than bimodal CI users who have electric stimulation in one ear via a CI and acoustic hearing contralateral to the CI. In other words bimodal CI users have different hearing in each ear.) We can use these two groups of patients, Bilateral CI and EAS, with different types of bilateral hearing to assess the value of interaural level difference (ILD) cues and interaural time difference (ITD) cues in localization and in speech understanding in real world environments. Interaural time and intensity differences are known to provide normal hearing listeners with the ability to localize and are thought to underlie spatial release from masking (SRM). To date, there is a single paper (Dunn et al., 2010) on localization in EAS users. Dunn reported that EAS users are able to localize although not as well as normal hearing listeners. The study, however, lacked controls for the frequency information used in localization. There is a consensus that bilateral users have ILD sensitivity but do not have access to ITD cues (Grantham et al., 2007). Loizou et al. (2009) report bilateral CI users do not benefit from spatial release from masking, presumably due to the absence of ITD cues. If ITD cues are necessary for SRM in real world noise environments, EAS patients may benefit more in these environments than bilateral CI patients. The specific aims of this research are to determine (i) which underlying mechanism, ITD, ILD or both, underlie localization by the two groups, (ii) whether ITD or ILD cues provide a greater advantage when CI listeners are placed in difficult real world listening situations, and (iii) if there is a relationship between the availability of interaural ITD and ILD cues and SRM. The answers to these questions will shape our understanding of cochlear implant benefit and provide information to patients about real world benefits of CIs. The research design is a 2(groups=bilateral CI and EAS) X 3 (low-pass, high-pass, wideband noise) repeated measures ANOVA for localization ability from the three noise conditions and a 2 (groups = bilateral CI and EAS) X 2 (mode of listening and noise condition) repeated measures ANOVA for speech perception in noise. An analysis will be calculated to determine if performance on localization correlates with spatial release from masking. PUBLIC HEALTH RELEVANCE: The implications for a potential cochlear implant patient who is trying to decide between bilateral versus EAS could justifiably impact the decision of the patient, the surgeon, the audiologist, the tax payers, and even the insurance companies. This information will provide potential CI users and hearing health care providers with the necessary information to make an informed decision regarding expected outcomes.