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The physiological bases and perceptual consequences of 'hidden' noise-induced hearing loss

“隐藏”噪声引起的听力损失的生理基础和感知后果

基本信息

批准号：
MR/L003589/1
负责人：
Chris Plack
金额：
$ 147.57万
依托单位：
University of Manchester
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2014
资助国家：
英国
起止时间：
2014 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=MR%2FL003589%2F1
关键词：
physiological bases perceptual consequences hidden

项目摘要

Noise exposure is the main cause of preventable hearing loss worldwide. Noise exposure occurs in the workplace, such as in noisy factories, and recreationally, through the use of personal music players and attendance at nightclubs and live music events. Hearing loss is usually diagnosed using pure tone audiometry, which measures the sensitivity of the ear to quiet sounds by determining the levels of tones that can just be heard at several test frequencies. Until recently, it had been assumed that hearing loss results mainly from damage to the sensory hair cells in the cochlea, the part of the ear that converts acoustic vibrations into electrical impulses in the auditory nerve. However, recent results from animal studies suggest that moderate noise exposure can cause substantial damage to the auditory nerve, even when the hair cells are unaffected. Crucially, the results suggest that such damage does not affect sensitivity to quiet sounds, and hence is not detectable by pure tone audiometry. Hearing loss that is not detectable by conventional audiometry is sometimes called "hidden" hearing loss.Auditory nerve damage degrades the information that is carried by the nerve from the ear to the brain. Some studies suggest that people with a history of noise exposure, but with normal hearing sensitivity as measured by pure tone audiometry, have problems with sound discrimination, including understanding speech in noisy environments. However, to date no direct link has been made between the physiological results and the perceptual deficits. It is also possible that damage to the auditory nerve leads to tinnitus (perception of sound in the absence of external sound: "ringing in the ear") and hyperacusis (diminished tolerance of moderate-to-high level sounds). Hidden hearing loss is potentially a huge problem. Substantial numbers of people, probably millions in the UK alone, are routinely exposed to occupational and/or recreational noise levels similar to, or greater than, those used in the animal studies. A large UK study found that one in seven adults aged 17-30 reported "great difficulty" hearing speech in noisy backgrounds, while only one in fifty had impaired sensitivity as measured by pure tone audiometry. Hidden loss leads to a reduction in quality of life, and is likely to be predictive of more severe hearing loss in old age. Hence, hidden hearing loss is a major public health issue, which demands a comprehensive investigation.Our programme is far-reaching and ambitious, involving three internationally renowned institutions across the UK and US, and a wide range of scientific methodologies. These include physiological and perceptual measures on both animals and humans. Our approach is to use overlapping methodologies across the animal and human studies so that we can understand the perceptual deficits experienced by humans in terms of the underlying physiological mechanisms. We will estimate the prevalence of hidden loss in young adults, and the impact of hidden loss on everyday tasks such as speech and music perception. We will also determine how hidden loss is related to tinnitus and hyperacusis. Finally, we will use our results to develop a sensitive diagnostic test that can be used to detect hidden loss, hence allowing the detection of hearing loss that is undetected by current clinical procedures.Our research is expected to lead to a number of benefits. A diagnostic test for hidden loss in the clinic, and for monitoring the hearing of workers, will allow identification of at-risk individuals, and provision of personalised healthcare advice, regarding, for example, ways to reduce noise exposure. Our research could also result in a reduction in legal noise exposure limits. These measures will help prevent hidden loss, improve patient outcomes, and reduce usage of healthcare resources. Longer-term, there may be the possibility of reversing auditory nerve damage by replacing lost nerve fibres using stem cells.

噪音暴露是世界范围内可预防的听力损失的主要原因。噪音暴露发生在工作场所，如嘈杂的工厂，以及娱乐场所，通过使用个人音乐播放器和参加夜总会和现场音乐活动。听力损失通常是通过纯音测听来诊断的，纯音测听是通过确定在几个测试频率下只能听到的音调水平来测量耳朵对安静声音的敏感度。直到最近，人们一直认为听力损失主要是由耳蜗感觉毛细胞受损造成的。耳蜗是耳朵的一部分，负责将声音振动转化为听神经中的电脉冲。然而，最近的动物研究结果表明，即使毛细胞没有受到影响，适度的噪音暴露也会对听神经造成实质性的损害。至关重要的是，研究结果表明，这种损伤不会影响对安静声音的敏感度，因此无法通过纯音听力学检测到。传统测听法检测不到的听力损失有时被称为“隐性”听力损失。听神经损伤降低了由神经从耳朵传递到大脑的信息。一些研究表明，有噪音暴露史的人，但纯音听力学测量的听力灵敏度正常，在声音识别方面存在问题，包括在嘈杂环境中理解语音。然而，到目前为止，生理结果和知觉缺陷之间还没有直接的联系。听神经损伤也可能导致耳鸣（在没有外界声音的情况下感知声音：“耳鸣”）和听觉亢进（对中高音量声音的耐受性降低）。隐性听力损失是一个潜在的大问题。大量的人，仅在英国就可能有数百万人，经常暴露在与动物研究中使用的噪音水平相似或更大的职业和/或娱乐噪音中。英国的一项大型研究发现，在17-30岁的成年人中，有七分之一的人在嘈杂的背景下听力“非常困难”，而在纯音听力测量中，只有五分之一的人听力受损。隐性听力损失导致生活质量下降，可能预示着老年时更严重的听力损失。因此，隐性听力损失是一个重大的公共卫生问题，需要进行全面的调查。我们的项目影响深远，雄心勃勃，涉及英国和美国的三家国际知名机构，以及广泛的科学方法。这些包括对动物和人类的生理和知觉测量。我们的方法是在动物和人类研究中使用重叠的方法，这样我们就可以从潜在的生理机制方面理解人类所经历的感知缺陷。我们将估计年轻人中隐性损失的患病率，以及隐性损失对日常任务（如语音和音乐感知）的影响。我们还将确定隐性损失与耳鸣和听觉亢进的关系。最后，我们将利用我们的结果开发一种灵敏的诊断测试，可用于检测隐性听力损失，从而允许检测当前临床程序未检测到的听力损失。我们的研究有望带来许多好处。一项针对诊所隐性损失的诊断测试，以及监测工人听力的测试，将允许识别有风险的个人，并提供个性化的医疗建议，例如，关于减少噪音暴露的方法。我们的研究还可以降低法定噪音暴露限制。这些措施将有助于防止隐性损失，改善患者的治疗效果，并减少医疗资源的使用。长期来看，有可能通过使用干细胞替换失去的神经纤维来逆转听神经损伤。