Behavioral and Physiological Effects of Binaural Cue Distortion

描述（由申请人提供）：在空间中定位和隔离声源的能力对通信和环境意识很重要。正常听力（NH）的人听者有效地定位和分离声源的基础上，耳间的时间和水平差异（ITD和ILD） -双耳声线索声源方位。使用助听器（HAs）和人工耳蜗（CIs）的听障人士在检测这些线索的能力上往往会受到严重或严重的损害，从而导致在日常听力环境中出现严重的沟通困难。这种缺陷被认为是由患者因素引起的，如长期听觉剥夺导致中枢功能改变，以及临床设备限制，如信号处理的时间精度不足或自动增益控制算法的双边不对称。提高对双耳听力表现的信号相关限制的理解将导致对双耳系统的基本理解的增强，并可能导致临床设备技术和患者预后的改进。因此，本研究的长远目标是阐明双耳线索退化对声音定位和分离的影响，以提高对正常和受损双耳听力的理解。本研究的具体目的是：(1)表征耳间去相关和时变ILD压缩对正常听力人对ILD、ITD和虚拟声源位置的心理物理敏感性的影响；(2)表征这种扭曲对下丘神经元对ILD、ITD和虚拟声源方位的编码的影响。实验将整合(1)行为任务，包括辨别、颅内侧化和虚拟空间定位，以表征对控制和双耳退化刺激的心理物理敏感性，包括我们最近测量的实际双耳HA输出产生的模拟“设备处理”刺激；(2)体内细胞外记录技术，用于表征对控制和退化刺激的生理（神经）敏感性。行为和神经数据将使用Fisher信息来比较行为和神经双耳辨别的表现。在进行这些实验的同时，申请人将定期与临床医生（包括共同发起人）会面，并观察临床会议，以获得听力损失人士所面临的沟通和其他听力困难的额外视角。这些会议将丰富申请人的培训，并可能为未来实验的后续设计提供见解。本研究将通过加深对双耳听觉系统和双耳临床设备（特别是HAs）对双耳获益的外源性（信号相关）限制的基本理解来支持NIDCD的使命。

DESCRIPTION (provided by applicant): The ability to localize and segregate sound sources in space is important for communication and environmental awareness. Normal-hearing (NH) human listeners effectively localize and segregate sound sources on the basis of interaural time and level differences (ITD and ILD) - binaural acoustic cues to sound source azimuth. Hearing-impaired individuals who use hearing aids (HAs) and cochlear implants (CIs) are often significantly or profoundly impaired in their abilities to detect these cues, leading to significan communication difficulties in everyday listening environments. Such deficits are believed to arise from a combination of patient factors, such as prolonged auditory deprivation leading to altered central function, and clinical device limitations, such as inadequate temporal precision in signal processing or bilateral asymmetry in automatic gain control algorithms. An improved understanding of signal-related limitations on binaural hearing performance will lead to an enhanced basic understanding of the binaural system and may lead to consequent improvements in clinical device technology and patient outcomes. Therefore, the broad long-term goal of the proposed research is to elucidate the effects of binaural cue degradations on sound localization and segregation, toward improved understanding of normal and impaired binaural hearing. The specific aims of the proposed research are: (1) To characterize the effects of interaural decorrelation and time-varying ILD compression on normal-hearing psychophysical sensitivity to ILD, ITD and virtual sound source location and (2) to characterize the effects of such distortions on the encoding of ILD, ITD and virtual sound source azimuth by neurons of the inferior colliculus. Experiments will integrate (1) behavioral tasks including discrimination, intracranial lateralization, and virtual space localization for characterization of psychophysical sensitivity to control and binaurally degraded stimuli, including simulated "device-processed" stimuli generated from our recent measurements of actual bilateral HA outputs and (2) in vivo extracellular recording techniques for characterization of physiological (neural) sensitivity to control and degraded stimuli. Behavioral and neural data will be related using Fisher information to compare behavioral and neural binaural discrimination performance. Simultaneous with these experiments, the Applicant will regularly meet with clinicians (including the Co- Sponsor) and observe clinical sessions to gain additional perspective on communicative and other listening difficulties faced by people with hearing loss. Such meetings will enrich the Applicant's training and may provide insights for the design of follow-up of future experiments. The proposed work will support the mission of NIDCD by advancing basic understanding of the binaural auditory system and exogenous (signal-related) limitations on binaural benefit from bilateral clinical devices (especially HAs).