Physiological Assessment of Auditory Processing Disorders in TBI

由高强度冲击波暴露引起的轻度创伤性脑损伤(TBI)是 耐受自由和手术的退伍军人最常见的伤害 伊拉克自由。最近的研究表明，这些退伍军人中的许多人都可能患有慢性 尽管听力阈值正常，但处理听觉信息仍有困难。其中一些 最常报告的问题包括在嘈杂或分散注意力的情况下说话困难 环境、冗长演讲和回忆指令列表的问题，以及 电话里的困难。目前，人们对爆炸暴露如何影响人体健康知之甚少 产生这种缺陷的听觉系统的生理学，也没有潜在的贡献 与听觉处理有关的认知障碍并存。在目前的研究中，我们的目标是 将电生理学与行为测试相结合，更好地了解爆炸是如何- 暴露和脑外伤塑造了声音的神经编码和辨别，并探讨了 认知因素对听觉加工的影响。我们研究的长期目标是 计划是开发准确可靠地反映听觉的电生理工具 功能，可用于提高成人患者的临床诊断和康复努力 患有后天听觉处理障碍。我们这个CDA-2研究计划的总体目标， 这是实现我们长期目标的下一步，是系统地评估 皮层和认知听觉诱发电位(AEP)检测在揭示慢性阻塞性肺疾病中的作用 有冲击波暴露/脑外伤病史的退伍军人听觉处理的生理学变化 检查这些客观的生理测量和行为之间的关系 听力的测量。具体地说，我们将1)确定爆炸暴露和TBI 影响神经对声音的跨域识别，包括频率、时间、强度和 听觉皮质水平的双耳整合，2)冲击波暴露/脑外伤对双耳整合的影响 使用认知听觉诱发电位对听觉编码的认知调制，以及3)评估关系 皮层和认知AEP测量与心理测量学行为测量之间的关系 听觉处理的能力。我们假设，暴露在爆炸中的退伍军人将在 从较高的检测阈值可以看出，对声音特征的皮层编码 在爆炸中声音的变化和降低的幅度导致声音特性的变化- 暴露/脑外伤退伍军人与年龄和听力匹配的对照组参与者进行比较。我们进一步 预测冲击波暴露/脑外伤退伍军人对声音的认知控制能力会下降 与对照组参与者进行编码比较，皮质和认知AEP指数将 与听力的行为指标有很好的相关性。这项研究的结果 建议包括更好地理解自下而上与自上而下对听觉的贡献 有冲击波暴露和颅脑损伤的退伍军人的处理障碍，将作为 开发生理工具来评估这一人群中的听觉问题的起点。 这些结果预计将产生积极影响，因为它们增加了我们的知识 冲击波暴露和脑外伤对听觉功能的影响，并将提供重要的一步 期待改善对这些患者的临床护理。这项工作将具有重大意义，因为 预计它将在诊断和管理方面具有广泛的翻译意义 患有获得性听觉处理障碍的成人患者。

Mild traumatic brain injury (TBI) stemming from exposure to high-intensity blasts is one of the most prevalent injuries sustained by Veterans of Operation Enduring Freedom and Operation Iraqi Freedom. Recent research indicates that many of these Veterans can suffer from chronic difficulties processing auditory information in spite of normal hearing thresholds. Some of the most commonly reported problems include difficulty with speech in noisy or distracting environments, problems with long running speech and recalling lists of instructions, and difficulties on the telephone. Currently, little is known regarding how blast exposure affects the physiology of the auditory system to produce such deficits, nor the potential contributions of comorbid cognitive disorders to auditory processing concerns. In the current study, we aim to use electrophysiology in combination with behavioral testing to better understand how blast- exposure and TBI shape the neural encoding and discrimination of sound, and to probe the influence of cognitive factors on auditory processing. The long term goal of our research program is to develop electrophysiological tools which accurately and reliably reflect auditory function and can be used to improve clinical diagnosis and rehabilitation efforts of adult patients with acquired auditory processing disorder. Our overall objective for this CDA-2 research plan, which is the next step toward attainment of our long-term goal, is to systematically evaluate the utility of cortical and cognitive auditory evoked potentials (AEP) measures to reveal chronic physiological changes in auditory processing in Veterans with previous blast-exposure/TBI, and examine the relationship between these objective physiological measures and behavioral measures of hearing ability. Specifically, we will 1) determine how blast exposure and TBI affect neural discrimination of sound across domains including frequency, timing, intensity, and binaural integration at the level of the auditory cortex, 2) the impact of blast exposure/TBI on cognitive modulation of auditory encoding using cognitive AEPs, and 3) Assess the relationship between cortical and cognitive AEP measures and psychometrically based behavioral measures of auditory processing. We hypothesize that blast-exposed Veterans will demonstrate deficits in both cortical encoding of sound characteristics as evidenced by higher thresholds for detecting changes in sound and reduced amplitudes to changes in sound characteristics in blast- exposed/TBI Veterans compared to age- and hearing-matched control participants. We further predict that blast-exposed/TBI Veterans will show decreased cognitive control of sound encoding compared to control participants, and that cortical and cognitive AEP indices will be well correlated with behavioral measures of hearing ability. The outcomes of this research proposal include a better understanding of the bottom-up vs top-down contributions to auditory processing disorders in Veterans with previous blast-exposure and TBI and will serve as a starting point for developing physiological tools to evaluate auditory concerns in this population. These outcomes are expected to have a positive impact because they increase our knowledge of the impact of blast exposure and TBI on auditory function and will provide a significant step forward towards improved clinical care for these patients. This work will be significant because it is expected to have broad translational implications on the diagnosis and management of adult patients suffering from acquired auditory processing disorders.