Behavioral and physiological changes in acoustic-electrical pitch matching

描述（由申请人提供）：语言失聪成人人工耳蜗（CI）使用者面临的一个挑战是，输入的声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。虽然侦听器可以清楚地适应频率不匹配，但缺乏能够使我们将对频率不匹配的适应与CI用户面临的其他失真区分开来的信息。在提出的实验中，我们通过检查对侧耳朵有残余听力的CI用户来解决这个问题。考虑到频率不匹配通常被感知为相对于存储在长期记忆中的表征的信号的音高变化，我们计划比较电刺激引起的音高感知与对侧耳的声学听觉，并观察这些感知是否随时间而变化。我们的假设是，这种电音高感知的变化表明对频率不匹配的适应。根据这一逻辑，我们计划通过三个实验来解决频率失配的量化适应问题。在第一个实验中，我们计划要求对侧耳有足够残余听力的CI患者将给定电极刺激引起的音高与呈现给声学听力耳的音调引起的音高相匹配。我们计划在设备使用的前两年跟踪这些音高匹配，并确定音高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，我们计划确定耳蜗的大小和电极在耳蜗内的位置。由此，我们可以估计给定CI用户面临的频率不匹配的数量。然后，使用实验1中获得的数据，我们将探索更大的初始频率错配是否与更大的自适应量相关，还是与更差的整体性能相关。最后，在第三个实验中，我们计划在设备使用的前两年跟踪P1-N1-P2复合体中电声诱发的相互作用，以获得对频率不匹配的适应的客观测量。综上所述，这些拟议的实验代表了首次尝试量化特定患者频率不匹配的数量，以及他们能够适应这种不匹配的程度。因此，他们解决了在人工耳蜗领域知识的严重缺乏。更重要的是，从这些提议的项目中获得的信息有可能直接塑造未来人工耳蜗的装配，并可能对患者护理产生影响。在这里，我们建议使用新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转化成分，最终可能有利于听力受损人群的公共健康。

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. PUBLIC HEALTH RELEVANCE: Cochlear implants help many people hear, but the signal they provide can be significantly different from that provided by an intact auditory system. Patients who had acoustic hearing, lost it, and then received a cochlear implant, must adapt to the mismatch between the signal provided by the implant and the representations of speech that are stored in their long-term memory. The present study will investigate this adaptation process using behavioral and physiological measures, and this information may assist clinicians in helping patients optimize the benefit they obtain from their device.