Behavioral and Physiological changes in acoustic-electrical pitch matching

描述(由申请人提供)：语言后聋的成年人工耳蜗术(CI)使用者面临的一个挑战是，传入的声学信号与植入物刺激的神经元的特征频率之间可能存在频率不匹配。虽然听众可以清楚地适应频率不匹配，但缺乏信息可以让我们将对频率不匹配的适应与CI用户面临的其他扭曲区分开来。在拟议的实验中，我们通过检查对侧耳有残余听力的CI使用者来解决这个问题。鉴于频率不匹配经常被感知为信号音调相对于长期记忆中存储的表示的变化，我们计划将电刺激引起的音调感知与对侧耳的声学听觉感知进行比较，并观察这些感知是否随着时间的推移而变化。我们的假设是，电音高知觉的这种变化表明适应了频率失配。根据这一逻辑，我们计划通过三个实验来解决量化适应频率失配的问题。在第一个实验中，我们计划让对侧耳有足够剩余听力的CI患者将刺激给定电极引起的音调与提供给声听力耳朵的音调匹配。我们计划在设备使用的头两年跟踪这些音调匹配，并确定音调感知的变化是否也与语音感知的变化有关。在第二个实验中，我们计划确定耳蜗大小和电极在耳蜗内的位置。由此，我们可以估计给定CI用户面临的频率失配量。然后，使用实验1中获得的数据，我们将探索较大的初始频率失配是否与较大数量的适应相关，或与较差的整体表现相关。最后，在第三个实验中，我们计划跟踪设备使用的前两年P1-N1-P2复合体中的电-声诱发相互作用，以获得对频率失配的适应的客观测量。总而言之，这些拟议的实验代表了量化给定患者的频率失配量以及他们能够适应这种失配的程度的首批尝试之一。因此，他们解决了在人工耳蜗术领域严重缺乏知识的问题。更重要的是，从这些拟议的项目中获得的信息有可能直接决定未来人工耳蜗的安装，并可能对患者护理产生影响。在这里，我们建议使用新的技术来解决这一关键问题，因此，我们相信拟议的研究具有很强的翻译成分，最终可能有利于听障人群的公共健康。

DESCRIPTION (provided by applicant): One challenge facing a postlingually-deafened adult cochlear implant (CI) user is the possibility that there may be a frequency mismatch between the incoming acoustic signal and the characteristic frequency of the neurons stimulated by the implant. While listeners can clearly adapt to frequency mismatches, there is a lack of information that can allow us to separate the adaptation to frequency mismatches from other distortions that CI users face. In the proposed experiments, we address this issue by examining CI users who have residual hearing in the contralateral ear. Given that frequency mismatches are often heard perceptually as a change in the pitch of the signal relative to the representation stored in long-term memory, we plan to compare the pitch percepts elicited by electrical stimulation with those from the acoustic hearing in the contralateral ear, and observe whether those percepts change over time. Our assumption is that such changes in electrical pitch perception indicate adaptation to a frequency mismatch. By this line of logic, we plan to address the issue of quantifying adaptation to frequency mismatch via three experiments. In the first experiment, we plan to ask CI patients who have sufficient residual hearing in the contralateral ear to match the pitch elicited by stimulation of a given electrode to the pitch elicited by a tone presented to the acoustic-hearing ear. We plan to follow these pitch matches over the first two years of device use, and determine whether changes in pitch perception are also related to changes in speech perception. In the second experiment, we plan to determine the cochlear size and the location of the electrode within the cochlea. From this, we can estimate the amount of frequency mismatch that a given CI user faces. Then, using the data obtained in Experiment 1, we will explore whether larger initial frequency mismatches are associated with larger amounts of adaptation, or with worse overall performance. Finally, in the third experiment, we plan to track electric-acoustic evoked interactions in the P1-N1-P2 complex over the first two years of device use in order to obtain an objective measure of adaptation to frequency mismatch. Taken together, these proposed experiments represent one of the first attempts to quantify the amount of frequency mismatch a given patient has, and the extent to which they are able to adapt to that mismatch. As such, they address a significant lack of knowledge in the cochlear implant field. More importantly, the information gained from these proposed projects has the potential to directly shape future fitting of cochlear implants, and may have an effect on patient care. Here, we propose the use of novel techniques to address this key issue, and as such, we believe that the proposed research has a strong translational component that may ultimately benefit public health for hearing-impaired populations.