Effects of sensorineural loss on robust speech coding

感音神经损失对鲁棒语音编码的影响

• 批准号: 7146526
• 负责人: Michael G Heinz
• 金额: $ 3.47万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-12-13 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7146526
• 关键词: acoustic nerve; auditory nuclei; auditory stimulus; biological models; cats; cochlea; disease /disorder model; ear hair cell; electrophysiology; hearing aids; neural information processing; neurons; neurophysiology; neurosurgery; noise; sensorineural hearing loss; sound frequency; speech recognition

DESCRIPTION (provided by applicant): Speech perception by listeners with normal hearing is robust across a wide variety of conditions, whereas people with sensorineural hearing loss (SNHL) typically show much less robust speech perception. The long term goal of these studies is to understand the neural information and neural mechanisms that underlie robust speech perception in order to guide the development of novel strategies for auditory prostheses, which currently have particular difficulty restoring normal speech perception in adverse conditions. The proposed experiments focus on the idea that nonlinearities in auditory-nerve (AN) spatio-temporal response patterns, which are associated with nonlinear cochlear tuning and are produced by the physiologically vulnerable outer hair cells, may contribute to robust speech coding. If true, this result would suggest the need for novel strategies for hearing aids, which currently do not attempt to restore normal spatio-temporal patterns in the AN. Two specific aims focus on the effects of SNHL on enhancements that occur between the AN and cochlear nucleus (CN) in the coding of both spectral and temporal-envelope modulations, two important properties of speech signals. First, spectral coding will be evaluated by measuring the responses of AN fibers and CN neurons to vowel-like stimuli with important spectral features shifted near the best frequency of each neuron. Responses will be measured as a function of level, both in quiet and in background noise, to evaluate robust speech coding in cats with normal hearing and in cats with a noise induced hearing loss. The potential for nonlinear spatio-temporal response patterns to enhance speech coding will be evaluated based on responses of a simple cross-frequency coincidence detector predicted from measured AN responses. Second, the effects of SNHL on the robustness of temporal-envelope coding will be evaluated by quantifying temporal and spectral representations of the fundamental frequency (F0) from the vowel responses collected in Aim 1. If different effects of SNHL on periodicity and temporal-place measures of F0 were observed in the AN and CN, this result would constrain the possible neural mechanisms underlying enhanced envelope coding in the CN as well as perceptual theories of voice-pitch coding. The difficulty hearing-impaired listeners have in understanding speech in complex acoustic environments may be due in part to a reduced ability to segregate sound sources based on voice pitch.

描述（由申请人提供）：听力正常的听众的言语感知在各种条件下都很稳健，而感音神经性听力损失 (SNHL) 的人通常表现出不太稳健的言语感知。这些研究的长期目标是了解鲁棒语音感知背后的神经信息和神经机制，以指导听觉假体新策略的开发，目前听觉假体在不利条件下恢复正常语音感知特别困难。所提出的实验重点关注听觉神经（AN）时空响应模式中的非线性（与非线性耳蜗调谐相关并由生理上脆弱的外毛细胞产生）可能有助于稳健的语音编码。如果属实，这一结果表明需要新的助听器策略，目前助听器并不试图恢复 AN 中的正常时空模式。两个具体目标集中在 SNHL 对 AN 和耳蜗核 (CN) 之间在频谱和时间包络调制（语音信号的两个重要属性）编码中的增强的影响。首先，将通过测量 AN 纤维和 CN 神经元对元音样刺激的响应来评估频谱编码，其中重要的频谱特征移动到每个神经元的最佳频率附近。将在安静和背景噪声中测量响应作为电平的函数，以评估听力正常的猫和噪声引起的听力损失的猫的鲁棒语音编码。非线性时空响应模式增强语音编码的潜力将根据从测量的 AN 响应预测的简单跨频重合检测器的响应进行评估。其次，SNHL 对时间包络编码鲁棒性的影响将通过量化目标 1 中收集的元音响应中基频 (F0) 的时间和频谱表示来评估。如果 SNHL 对周期性和时间位置的不同影响在 AN 和 CN 中观察到 F0 的测量，这一结果将限制 CN 中增强包络编码的可能神经机制以及音调编码的感知理论。听力受损的听众在复杂的声学环境中理解语音的困难可能部分是由于基于音调分离声源的能力降低。