HEARING HAZARD ASSOCIATED WITH INDUSTRIAL NOISE EXPOSURE

许多工业噪声环境的特点是高噪声 碰撞噪声的级别总是叠加在一个 连续不断的背景噪声本身就是非常“峰值”的(高 峰度)，即具有非高斯分布的幅度。这个 有限的人口统计数据表明，这样的环境 导致听力损失的风险极高 反复曝光。我们的实验结果来自暴露的动物 符合连续噪声和冲击噪声的理想化组合 人口统计数据显示听力恶化 暴露在这样的噪音组合下造成的损失。有一个 普遍共识是，到目前为止，我们还没有足够的 复杂声学环境的描述符或量度 可用于评估对听力和 建立暴露标准。对听力的危害来自 将使用栗鼠作为研究对象来研究复杂的噪声环境 一个动物模型。工业噪声环境将在 两种完全不同的方式：(1)通过产生理想化 连续噪声的指定频带的组合 添加了离散的撞击噪声序列。通过研究这些影响 参数变化对实验动物听力的影响 我们可以从中了解到相互作用的局限性 这两类噪音。虽然我们目前正在追查这一点 方法，并建议对这些研究进行有限的扩展， 这种方法有实际的局限性。(2)通过数字生成一个 脉冲性(峰度)可能存在的连续噪声 受到严密控制。我们还将能够控制从哪一个 可听频谱的一部分，脉冲峰值的能量 出现了。这种方法将产生最逼真的建模和 拥有生成索引的最大希望，根据该索引 评估几乎任何工业噪音所造成的危害 环境。我们建议合成这样的噪音并曝光 动物群体对这些合成噪音条件的反应。这个 峰度(B2)、光谱变量和能级将被系统地 多种多样。听力损伤将根据听力进行评估 变化(阈值和调谐曲线)使用诱发的 听觉反应和耳蜗区感觉细胞的丧失。我们会 测试高B2噪声暴露更多的假设 对听力的危害比同样的低B2值暴露更危险 能量，这种效应是频率相关的。事实的真相 这一声明将使我们能够开发出一种物理测量 复杂的噪声暴露(与我们的指数相关 听力创伤)，以评估对听力的危害。

Many industrial noise environments are characterized by high levels of impact noise which are invariably superimposed on a continuous background noise which itself is very "peaked" (high kurtosis), i.e., has a non-Gaussian distribution of amplitudes. The limited demographic data available show that such environments pose an unusually high risk of hearing loss with prolonged or repeated exposures. Our laboratory results from animals exposed to idealized combinations of continuous and impact noise agree with the demographic data in showing an exacerbation of hearing loss following exposures to such a noise combination. There is a general consensus that we do not, as yet, have an adequate descriptor or measure of complex acoustic environments which can be used for the purpose of evaluating the risk to hearing and establishing exposure standards. The hearing hazards from complex noise environments will be studied using the chinchilla as an animal model. Industrial noise environments will be modeled in two totally different ways: (1) by producing idealized combinations of a specified band on continuous noise to which a discrete series of impact noises is added. By studying the effects of parameter variations on the hearing of experimental animals we can learn something of the limits of the interaction between these two classes of noise. While we are currently pursuing this approach, and propose a limited extension of these studies, the approach has practical limitations. (2) by digitally generating a continuous noise within which the impulsiveness (kurtosis) can be closely controlled. We will also be able to control from which part of the audible spectrum the energy for the impulsive peaks arises. This approach will yield the most realistic modeling and holds the greatest promise for producing an index by which to gauge the hazards posed by virtually any industrial noise environment. We propose to synthesize such noise and expose groups of animals to these synthesized noise conditions. The kurtosis (B2), spectral variables and level will be systemically varied. Hearing trauma will be assessed in terms of audibility changes (thresholds and tuning curves) measured using the evoked auditory response, and sensory cell losses in the cochlea. We will test the hypothesis that a high B2 noise exposure is more hazardous to hearing than is a low B2 exposure, of the same energy and that this effect is frequency dependent. The truth of this statement will allow us to develop a physical measure of a complex noise exposure, (which correlates with our indices of hearing trauma) for the purpose of evaluating hazards to hearing.