Across-Site Patterns of Perception with Cochlear Implants

描述（由申请人提供）：我们研究的长期目标是增加听力受损患者从人工耳蜗中获得的好处。该方法是改进自定义拟合策略，通过调整听觉假体语音处理器以满足个体患者的特征。要做到这一点，我们需要了解性能缺陷的根本原因。在我们的初步研究中，我们已经表明，大多数受试者可以区分语音识别所需的假肢刺激的基本空间和时间特征，但区分这些特征的能力取决于刺激的参数，包括刺激电极在电极阵列中的位置和响度增长所反映的输入输出功能。在单个人工耳蜗内，不同刺激部位的表现不同，不同刺激部位的变化模式是患者特异性的。这些结果提出了优化患者表现的两种策略。一种策略是创建一个处理器图，只利用那些在基本感知任务中表现最好的刺激点。为了支持这种方法，先前的研究表明，患者可以很好地忍受刺激位点数量的减少，并且当感知能力差的位点从处理器图中移除时，有时表现会有所改善。第二种策略是逐地单独优化增产参数。例如，我们知道，刺激水平可以通过调节来提高时间敏锐度。实施这两种策略需要更好地理解人工耳蜗跨部位感知模式的基本原理。具体来说，必须解决以下问题。(1)对于所有的知觉测量，跨站点的知觉模式在多大程度上相似？例如，导致时间感知差的潜在条件是否也会影响空间分辨率？(2)各种心理物理活动对语音识别的相对贡献是什么？例如，在必要时，以牺牲空间敏锐度为代价来提高时间敏锐度是否更好？(3)空间敏锐度和时间敏锐度对刺激水平的依赖性是否相似？这些问题将通过植入人体的心理物理和语音识别研究来解决。这项工作将加深我们对人工耳蜗语音识别性能跨学科差异机制的理解，并为建立和测试临床程序以提高个体患者的表现提供指导。

DESCRIPTION (provided by applicant): The long-term objective of our research is to increase the benefit that hearing impaired patients receive from their cochlear implant auditory prostheses. The approach is to improve the custom-fitting strategy by which the auditory prosthesis speech processor is adjusted to meet the characteristics of the individual patient. To do this, we need to understand the root causes of performance deficits. In our preliminary studies we have shown that most subjects can discriminate the fundamental spatial and temporal features of prosthetic stimulation needed for speech recognition, but that the ability to discriminate these features depends on the parameters of stimulation, including the location of the stimulating electrodes within their electrode array and input-output function as reflected in loudness growth. Performance varies from one stimulation site to another within an individual's cochlear implant and the pattern of this variation across stimulation sites is patient specific. These results suggest two strategies for optimizing patient performance. One strategy is to create a processor map that utilizes only those stimulation sites where performance on basic perceptual tasks is best. In support of this approach, previous studies have shown that patients tolerate a reduction in the number of stimulation sites well and that there is sometimes an improvement in performance when sites where perception is poor are removed from the processor map. A second strategy is to individually optimize the stimulation parameters on a site-by-site basis. It is known for example that stimulus level can be adjusted to improve temporal acuity. Implementation of these two strategies requires a better understanding of the basic principles underlying across-site patterns of perception in cochlear implants. Specifically, the following questions must be addressed. (1) To what extent are across-site patterns of perception similar for all perceptual measures? For example, do the underlying conditions that cause poor temporal perception also affect spatial resolution? (2) What are the relative contributions of the various psychophysical acuities to speech recognition? For example, would it be better to enhance temporal acuity at the expense, if necessary, of spatial acuity? (3) Do spatial and temporal acuity show similar dependency on stimulus level? These issues will be addressed using psychophysical and speech recognition studies in implanted human subjects. The work will deepen our understanding of the mechanisms underlying across-subject variation in speech recognition performance with cochlear implants and serve as a guide for establishing and testing clinical procedures to improve performance in individual patients.