Can noise-induced TTS cause persistent impairment of speech understanding?

描述(申请人提供)：最近的一项动物实验发现，暴露在足以产生暂时性阈值漂移(TTS)的噪声中的小鼠，即使它们的长期听力阈值保持正常，也会经历意想不到的、持续的阈值上的听觉功能变化。这一结果与职业噪声暴露指南和法规相冲突，后者假定可逆的阈值漂移(即TTS)与良性暴露水平相关。这项拟议的研究的目的是确定动物实验的结论是否适用于人类，以及是否如预测的那样，在噪声中导致言语理解障碍和/或响度增长的干扰感知(LG)。我们建议研究成年男性或女性(年龄21-50岁)，他们的听力阈值(HLS)正常，他们要么报告经常暴露在噪声和/或大声音乐中，并出现噪声诱发的TTS和/或耳鸣的症状(“暴露”组)，要么很少或根本没有暴露于噪声或噪声诱导的TTS或耳鸣的症状(“暴露”组)。志愿者将完成一份问卷，以确定他们的HLS确认后的症状和暴露情况。多达90名志愿者将参与以下行为测试：1)纯音HLS；2)使用改进的韵律测试在噪声中的单词得分；3)检测纯音正弦幅度调制的阈值。数据分析将对25名“暴露者”和25名未暴露者进行，这些人被选为与团体平均听力阈值最匹配的人。该提案涉及与听力损失预防跨部门计划和所有可能发生听力损失的Nora部门计划(农业、林业、建筑业、制造业、采矿业和运输业)相关的问题。要确认是否需要减少或消除可逆的阈值漂移，将需要中间结果，例如有关职业性噪声暴露和听力保护计划的公共政策变化。还需要重新设计听力保护器和改进的通信设备，以遵守减少危险暴露所需的更严格的噪声暴露准则。确定对这类设备的需求将有助于NIOSH的R2P倡议。如果这种影响被证明只有几个人能感受到，那么开发旨在弥补LG功能缺陷的设备可能更合适(见Brammer和Bernstein，2012)。因此，按照这里的建议，提供一种快速建立LG功能的方法，将有助于NIOSH的R2P倡议，使此类设备的开发成为可能。拟议研究的成果将在各次会议上发表，并在科学期刊上发表。

DESCRIPTION (provided by applicant): A recent animal experiment found that mice exposed to sufficient noise to produce temporary threshold shift (TTS) experienced unexpected, persistent suprathreshold changes in auditory function even though their long-term hearing thresholds remained normal. The results conflict with occupational noise exposure guidelines and regulations, which assume reversible threshold shifts (i.e., TTS) are associated with benign levels of exposure. The purpose of the proposed study is to establish whether the conclusion of the animal experiment is applicable to man and, as predicted, causes impaired speech understanding in noise and/or perturbed perception of loudness growth (LG). We propose to study adult males or females (aged 21 - 50 years) with normal audiometric hearing thresholds (HLs) who either report frequent exposure to noise and/or loud music and symptoms suggestive of noise-induced TTS and/or tinnitus ("exposed" group), or little or no exposure to noise or symptoms suggestive of noise-induced TTS or tinnitus ("unexposed" group). Volunteers will complete a questionnaire to establish symptoms and exposures after confirmation of their HLs. Up to 90 volunteers will participate in behavioral tests of: 1) pure-tone HLs; 2) word scores in noise using the Modified Rhyme Test, and; 3) thresholds for detecting sinusoidal amplitude modulation of pure tones. The analysis of data will be performed on 25 "exposed" and 25 "unexposed persons selected to best match the group mean audiometric thresholds. The proposal addresses an issue relevant to the Hearing Loss Prevention Cross-Sector Program and all NORA Sector Programs in which hearing loss may occur (Agriculture, Forestry, Construction, Manufacturing, Mining, and Transportation). Confirmation of the need to reduce or eliminate reversible threshold shifts will require intermediate outcomes such as public policy changes concerning occupational noise exposures and hearing conservation programs. There will also be a need for redesigned hearing protectors and improved communication devices to comply with the more restrictive noise exposure guidelines that would be required to reduce hazardous exposures. Identifying the need for such devices would contribute to NIOSH's r2P initiative. Should the effect prove to be experienced by only a few persons, it may be more appropriate to develop devices designed to compensate for a deficiency in the LG function (see Brammer and Bernstein, 2012). Hence, providing a rapid method for establishing the LG function, as proposed here, will contribute to NIOSH's r2P initiative by enabling the development of such devices. The outputs of the proposed research will be presented at conferences and published in scientific journals.