Effects of Blast Exposure on Sensory Gating and Speech Perception in Noise

 产品说明： 该CDA-1提案的目的是为Melissa Papesh博士提供必要的支持和指导，以便从基础科学研究过渡到退伍军人中枢听觉系统功能障碍的临床研究。具体而言，她目前的建议调查暴露于高强度冲击波对听觉信息的神经过滤的影响，以及爆炸相关的神经功能障碍导致在嘈杂背景中难以理解语音的可能性。该提案将为Papesh博士提供从事临床研究所需的工具和经验，并生成将用于申请未来资助（如CDA-2）的数据。职业计划是由课程，出版和成果介绍，心理健康的阴影，并从博士弗雷德里克加伦，柯蒂斯比林斯，罗伯特福尔默，马乔里韭菜，布雷特富勒指导。 爆炸相关伤害是最近军事冲突的标志性伤害，自2002年以来，估计有多达85万退伍军人遭受高强度爆炸。这些退伍军人中有很大一部分遭受影响感官和认知功能的长期后果。在听觉领域，爆炸暴露的退伍军人经常报告在嘈杂的环境中理解语音的困难增加，长时间谈话的困难，以及对环境声音的耐受性降低。即使发现听觉阈值正常，这种抱怨也很常见，从而表明功能障碍的中心来源。暴露于爆炸的退伍军人的认知抱怨通常包括注意力分散，选择性和持续性注意力差，记忆力和回忆力差。冲击波相关的认知和感觉主诉可能源于神经功能障碍的共同来源。目前的研究建议调查的假设，爆炸暴露损害大脑的部分参与前注意过滤的感官信息的相关内容。这个过滤感觉信息的过程，也被称为感觉门控，通常用于保护大脑的高级皮层中心免受无关或冗余感觉信息的轰击。这一假设得到了许多证据的支持，包括爆炸暴露的退伍军人和已知具有感觉门控障碍的人群所表达的症状之间的相似性，来自临床和动物研究的数据表明爆炸暴露可能会影响涉及感觉门控的大脑中心，脑电图（EEG）研究表明，与神经学正常的参与者相比，爆炸暴露的退伍军人的大脑显示出编码新刺激的能力降低。如果感觉门控在爆炸暴露后受损，这可能会导致在噪声中理解语音的困难，因为无法将神经资源用于处理感兴趣的语音流，同时过滤掉不相关的背景噪声。 本提案调查爆炸暴露损害感觉门控过程的程度，通过使用已建立的听觉EEG协议来评估爆炸暴露退伍军人和对照组中的感觉门控，对照组由年龄和听力匹配的先前部署的退伍军人组成，其PTSD严重程度与最后暴露的退伍军人组相似。这种精心匹配的对照组将有助于控制退伍军人人群中可能混淆检测结果的常见合并症。据推测，爆炸暴露的退伍军人将显示降低的能力，以编码新的听觉信息，以及增加冗余和不相关的听觉信息的神经表征相比，控制参与者。此外，关系 将通过比较感觉门控的EEG测量与SIN性能的行为测量来研究噪声中的语音（SIN）理解与感觉门控能力之间的关系。假设感觉门控能力和SIN理解之间存在正相关关系，因此感觉门控能力差的人在噪声中的言语理解测试中也表现不佳。

 DESCRIPTION: The purpose of this CDA-1 proposal is to provide Dr. Melissa Papesh with the support and mentorship necessary to make the transition from basic science research to clinical research of central auditory system dysfunction in Veterans. Specifically, her present proposal investigates the influence of exposure to high- intensity blast waves on the neural filtering of auditory information and the potential for blast-related neural dysfunction to contribute to difficulty understanding speech in noisy backgrounds. This proposal will provide Dr. Papesh with the tools and experience necessary to engage in clinical research and generate data which will be used in applying for future funding such as the CDA-2. The career plan is made up of coursework, publication and presentation of results, shadowing in mental health, and mentoring from Drs. Frederick Gallun, Curtis Billings, Robert Folmer, Marjorie Leek, and Bret Fuller. Blast-related injuries are the signature injuries of recent military conflicts, with estimates of up to 850,000 Veterans having suffered exposure to high-intensity blasts since 2002. A significant percentage of these Veterans suffer long term consequences affecting both sensory and cognitive function. Within the auditory domain, blast-exposed Veterans often report increased difficulty understanding speech in noisy environments, difficulty following long conversations, and decreased tolerance to environmental sound. Such complaints are common even when auditory thresholds are found to be normal, thus indicating a central source of dysfunction. Cognitive complaints of blast-exposed Veterans frequently include increased distractibility, poor selective and sustained attention, and poor memory and recall. Blast-related cognitive and sensory complaints may arise from a common source of neural dysfunction. The present research proposal investigates the hypothesis that blast exposure damages portions of the brain involved in the pre-attentive filtering of sensory information for relevant content. This process o filtering sensory information, also known as sensory gating, normally functions to protect higher cortical centers of the brain from being bombarded by irrelevant or redundant sensory information. This hypothesis is supported by numerous lines of evidence including the similarity between symptoms expressed by blast-exposed Veterans and those of populations known to have sensory gating impairments, data from clinical and animal studies indicating that blast exposure is likely to impact centers of the brain involved in sensory gating, and electroencephalographic (EEG) studies indicating that the brains of blast-exposed Veterans show a reduced ability to encode novel stimuli compared to neurologically normal participants. If sensory gating is impaired following blast exposure, this is likely to lead to difficulty with speeh understanding in noise due to an inability to devote neural resources to processing the speech stream of interest while filtering out irrelevant background noise. The present proposal investigates the extent to which blast exposure impairs sensory gating processes by using established auditory EEG protocols to assess sensory gating in blast-exposed Veterans and in a control group consisting of age- and hearing-matched previously-deployed Veterans with PTSD severity similar to the last-exposed Veteran group. This carefully matched control group will help to control for common comorbidities in the Veteran population which may otherwise confound test results. It is hypothesized that blast-exposed Veterans will display reduced ability to encode novel auditory information as well as increased neural representation of redundant and irrelevant auditory information compared to control participants. In addition, the relationship between speech-in-noise (SIN) understanding and sensory gating capacity will be investigated by comparing EEG measures of sensory gating with behavioral measures of SIN performance. A positive correlation between sensory gating capacity and SIN understanding is hypothesized such that those with poor sensory gating will also display poor performance on tests of speech understanding in noise.