Individual differences in brain networks supporting speech understanding in patientswith cochlear implants

摘要 听力受损的听众通常可以理解口语，但随着努力的增加， 认知资源远离其他过程，如注意力和记忆。一个重要的挑战是 因此，为了了解大脑如何处理退化的语音信号和认知过程， 是成功理解的关键植入人工耳蜗的成年听众是一个独特的群体， 他们通常已经适应了听觉剥夺多年， 深度听力损失，然后在植入后进行一定程度的听力恢复。以下 由于人工耳蜗植入而增加的听觉输入，个体听众能够 成功地识别语音，特别是在存在背景噪声的情况下，是非常可变的。先前 试图在大脑活动的潜在模式的背景下解释这种可变性是不成功的， 这在很大程度上是因为在存在植入物的情况下与神经成像相关的技术挑战 医疗设备已经阻止了对语音的神经反应的充分定位。我们的研究目标 是了解支持耳蜗植入者语音识别的认知系统， 利用这些系统的知识来改善行为结果。我们使用汇聚的证据 行为测量和功能性脑成像。我们利用高密度漫射光学 断层扫描（HD-DOT），一种光学脑成像的形式，它产生局部解剖定位指数， 皮层活动我们将绘制支持人工耳蜗听者语音理解的大脑网络图， 植入物，我们希望这些植入物与听力良好的听众所使用的植入物不同。我们将评估 努力倾听的神经标记物在多大程度上可以预测语音识别中的个体差异 在存在背景噪音的情况下取得成功。这些发现将有助于我们理解 人工耳蜗植入辅助语音识别在神经解剖学约束的框架，并开发更多 准确的结果测量。

Abstract Listeners with hearing impairment can often understand spoken language, but with increased effort, taking cognitive resources away from other processes such as attention and memory. An important challenge is therefore to understand how the brain copes with a degraded speech signal and the cognitive processes that are most critical to successful comprehension. Adult listeners with cochlear implants are a unique group in which to investigate effortful listening: They have typically adapted to auditory deprivation for a period of years of profound hearing loss, followed by some degree of hearing restoration following implantation. Following increased auditory input due to cochlear implantation, the degree to which individual listeners are able to successfully recognize speech, especially in the presence of background noise, is extremely variable. Previous attempts to explain this variability in the context of underlying patterns of brain activity have been unsuccessful, in large part because the technical challenges associated with neuroimaging in the presence of an implanted medical device have prevented adequate localization of neural responses to speech. The goal of our research is to understand the cognitive systems that support speech recognition in listeners with cochlear implants and to use knowledge about these systems to improve behavioral outcomes. We do so using converging evidence from behavioral measures and functional brain imaging. We make use of high-density diffuse optical tomography (HD-DOT), a form of optical brain imaging that produces anatomically-localized indices of regional cortical activity. We will map the brain networks supporting speech comprehension in listeners with cochlear implants, which we expect to differ from those engaged by listeners with good hearing. We will then evaluate the degree to which neural markers of effortful listening can predict individual differences in speech recognition success in the presence of background noise. Together the findings will help ground our understanding of cochlear implant-aided speech recognition in a neuroanatomically-constrained framework and develop more accurate outcome measures.