Adaptation to frequency mismatch in cochlear implant users

描述（由申请人提供）：耳蜗植入体（CI）利用耳蜗的音调结构，随着输入声音频率的增加，刺激逐渐靠近基底的区域。CI中的一个关键拟合参数是频率表，其中输入声频被分配给脑内电极。在当前的临床实践中，给定CI模型的所有用户接收基本相同的频率表。在语后听力受损的CI用户中，这种一刀切的方法可能会引入输入声频和被刺激的神经元的特征频率之间的失配。虽然人类听众可以适应这些扭曲，但越来越多的证据表明，有时这种适应过程可能是不完整的。适应过程及其可能的不完整性对语后听力受损CI人群的言语感知有重要影响。拟议的工作的第一个目的是衡量的程度和时间过程中，这一适应过程，这将在两个实验中进行探索。实验1将研究最近植入的CI用户，并跟踪他们一年，使用四种不同的方法来测量适应频率失配，辅以电池的语音感知，心理物理，认知和解剖测量。实验二将检查相同的问题，但与一组CI用户具有长期经验（至少一年）。这两个实验还有第二个目的：使用解剖学和认知测量来预测哪些个体更有可能对他们的临床频率表不完全适应。最后，实验3将解决所提出的研究的第三个目标：测试的假设，频率表旨在减少频率失配将提高语音感知分数CI用户谁显示不完全适应。拟议工作的一部分涉及开发和改进软件和硬件工具，以便于搜索可能有助于尽量减少频率失配的替代频率表。总之，本提案中描述的实验将提供关于语后听力受损CI用户对修改后的外周频率图的听觉适应性质的新见解，并且还将为负责安装这些设备的临床医生提供指导。像目前这样的研究将有助于将基础知识转化为临床实践，并将使临床实践更加数据和理论驱动。 公共卫生相关性：拟议的研究旨在了解人类听众如何适应听觉频率图的失真。这些知识可能有助于改善人工耳蜗植入用户的语音感知，这些用户难以适应编程到语音处理器中的标准频率表。该项目还旨在开发硬件和软件工具，以便将这些科学发现转化为实际的临床实践。

DESCRIPTION (provided by applicant): Cochlear implants (CIs) take advantage of the tonotopic structure of the cochlea, stimulating areas progressively closer to the base as the input sound frequency increases. One key fitting parameter in a CI is the frequency table wherein input acoustic frequencies are allocated to intracochlear electrodes. Under current clinical practice, all users of a given CI model receive basically the same frequency table. In postlingually hearing impaired CI users, this one-size-fits-all approach may introduce mismatches between input acoustic frequency and the characteristic frequency of the neurons that are stimulated. Although human listeners can adapt to these distortions, there is growing evidence that sometimes this adaptation process may be incomplete. Both the adaptation process and its possible incompleteness have important consequences to speech perception in the postlingually hearing impaired CI population. The first aim of the proposed work is to measure the extent and the time course of this adaptation process, which will be explored in two experiments. Experiment 1 will study recently implanted CI users and follow them for a year, using four different methods to measure adaptation to frequency mismatch, complemented by a battery of speech perception, psychophysical, cognitive, and anatomical measurements. Experiment two will examine the same questions but with a group of CI users with long term experience (at least one year). Both experiments will also have a second aim: using the anatomical and cognitive measures to predict which individuals are more likely to suffer incomplete adaptation to their clinical frequency tables. Lastly, Experiment 3 will address the third aim of the proposed research: to test the hypothesis that frequency tables intended to reduce frequency mismatch will improve speech perception scores in those CI users who show incomplete adaptation. Part of the proposed work involves developing and refining software and hardware tools to facilitate the search for alternative frequency tables that may help minimize frequency mismatch. In summary, the experiments described in this proposal will provide new insights about the nature of auditory adaptation to a modified peripheral frequency map by postlingually hearing impaired CI users, and will also provide guidance to the clinicians who are in charge of fitting these devices. Studies like the present ones will help translate basic knowledge into clinical practice, and will make clinical practice more data- and theory-driven. PUBLIC HEALTH RELEVANCE: The proposed research aims to understand how human listeners adapt to distortions in their auditory frequency maps. This knowledge may help improve speech perception in cochlear implant users who have difficulty adapting to the standard frequency tables programmed into their speech processors. The project also aims to develop the hardware and software tools that will allow the translation of these scientific findings into actual clinical practice.