INTENSITY PROCESSING IN EARS WITH SHIFTED THRESHOLDS

这项研究的总体目标是更好地理解 正常人和受损者强度处理的机制 耳朵。该提案的主要部分考察了两者之间的关系 响度增长和识别电平的小增量的能力， 这就是众所周知的强度分辨率。特别值得关注的是 已知或可能会修改强度分辨率的条件，以及 音量，如向复杂音调添加音调或检测到 宽带噪声(即过冲)开始时的短暂音调。 这项研究的另一个阶段考察了强度与 听神经瘤患者的分辨率和响度测试 认为适应是异常强度的原因的假说 在这些监听程序中进行处理。患有听神经瘤的受试者将使 对通常用于建模的激励模式模型的关键测试 听力正常和听力受损时的强度加工。第三个系列 实验考察了认知因素的作用(如记忆和 上下文)关于响度和强度分辨率。用不同的方法进行实验 刺激背景(例如，带有线索的前向掩蔽)将提供更多数据 与日常听力条件相关而不是固定刺激 上下文，但固定上下文和可变上下文都需要研究 将认知机制与感觉机制分开。这项拟议的研究 将提供对当前模型的关键测试，用于关联响度和 强度分辨率，并应提供对机制的洞察 这些现象背后的原因。来自这些实验的数据也应该 在Hering假体的设计和装配中被证明是有用的，例如在 人工耳蜗术中通道独立性的评估。

The overall goal of this research is to develop a better understanding of the mechanisms that underlie intensity processing in normal and impaired ears. A major portion of this proposal examines the relation between loudness growth and the ability to identify small increments in level, which is known as intensity resolution. Of particular interest are conditions that are known or ar likely to modify intensity resolution and loudness, such as adding tones to a complex tone or the detection of a brief tone during the onset oa a broadband noise (i.e., overshoot). Another phase of this research examines the relation between intensity resolution and loudness in individuals with acoustic tumors to test the hypothesis that adaptation is responsible for the abnormal intensity processing in these listeners. Subjects with acoustic tumors will enable a critical test of excitation-pattern models invoked typically for modeling intensity processing in normal and impaired hearing. A third series of experiments examines the role of cognitive factors (such as memory and context) on loudness and intensity resolution. Experiments with varied stimulus contexts (e.g., forward masking with cues) will provide data more relevant to everyday listening conditions than those from fixed stimulus contexts, but both fixed and variable contexts need to be studied to separate cognitive mechanisms from sensory ones. This proposed research will provide critical tests of current models for relating loudness and intensity resolution and should provide insights into the mechanisms underlying these phenomena. The data from these experiments also should prove useful in the design and fitting of hering prostheses, such as in the evaluation of channel independence in cochlear implants.