MODELS OF SPEECH PERCEPTION BY COCHLEAR IMPLANT USERS

本研究项目的长期目标是了解人工耳蜗使用者的语音机制，并在此过程中了解心理物理特征的个体差异，这可能解释人工耳蜗语音感知的个体差异。从这项研究中获得的见解将推进我们对语音感知和适应外围频率图主要变化的基本知识。项目一的具体目标是预测单个人工耳蜗使用者的音素识别，基于他们对特定感知维度的辨别。为了实现这一目标，我们提出开发多通道CI用户语音感知的多维音素识别（MPI）模型。这些基于心理物理的解释模型：它们不只是试图根据心理物理测试的表现来预测语音感知，它们还提供了关于CI用户如何编码和处理输入听觉信号以识别不同语音的严格和可验证的假设。MPI模式已经为语言感知的各种实验发现提供了可能的心理物理解释。项目II解决了CI用户对电刺激引起的感知的适应问题，由于刺激电极的位置比正常位置更低，因此电刺激引起的感知比声刺激引起的感知音调更高。我们建议测量CI用户对这种比正常水平更低的刺激所表现出的适应的时间过程、程度和可能的局限性。这个目标很重要，不仅因为它将为CI的言语感知提供临床和科学上有用的见解，而且因为CI人群提供了一个独特的机会来研究人类对修改频率图的适应，因此可能使我们获得关于成人中枢听觉系统可塑性的新知识。使用项目1中开发的MPI模型，我们将能够获得CI用户对高于正常水平的增产的适应程度的定量估计。

The long term goal of this research project is to understand the mechanistic that underlie of speech sounds by cochlear implant (CI) users and, in so doing, gain an understanding of the individual differences in psychophysical characteristics which may explain individual differences in speech perception with a CI. Insights gained from this research will advance our basic knowledge about speech perception and adaptation to major change in the peripheral frequency map. The specific aim of Project I is to predict phoneme identification of individual cochlear implant users, based on their discrimination along specified perceptual dimensions. To achieve this aim we proposed to develop Multi-dimensional Phoneme Identification (MPI) models of speech perception by multi-channel CI users. These psychophysically- based models of explanatory: they do not simply attempt to predict speech perception based on performance in psychophysical tests, they also provide strict and verifiable hypotheses about how CI users encode and process the input auditory signal to identify different speech sounds. The MPI mode has already provided insight into possible psychophysical accounts of a variety of experimental findings in speech perception. Project II addresses the adaptation show by CI users to the percepts elicited by electrical stimulation, which are of higher pitch than the percepts elicited by acoustic stimulation, due to the more- basal-than-normal location of the stimulating electrodes. We propose to measure the time course, the extent, and the possible limitations of the adaptation shown by CI users in response to this more-basal-than-normal stimulation. This goal is important not only because it will provide clinically and scientifically useful insights about speech perception with a CI, but also because the CI population presents a unique opportunity to investigate human adaptation to a modified frequency map, and may therefore allow us to obtain new knowledge about plasticity of the central auditory system in adults. Using the MPI models developed in Project I, we will be able to obtain quantitative estimates of a CI users' adaptation to more-basal-than-normal stimulation.