Redundant Information Is Sometimes More Beneficial Than Spatial Information to Understand Speech in Noise
Redundant Information Is Sometimes More Beneficial Than Spatial Information to Understand Speech in Noise
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DOI：
10.1097/aud.0000000000000660
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发表时间：
2019-05-01
期刊：
影响因子：
3.7
通讯作者：
Francart, Tom
中科院分区：
文献类型：
--
作者：
Dieudonne, Benjamin;Francart, Tom
目标：建立一个框架来明确定义和关联语音理解中的不同空间效应：头部阴影、冗余、静噪、掩蔽空间释放 (SRM) 等。接下来，研究耳间时间和声级差异对语音理解中这些空间效应的贡献，以及掩蔽噪声类型如何影响这种效应。设计：在我们的框架中，SRM 的独特特征是头部阴影、双耳冗余和双耳静噪的线性组合。后两个术语组合成一个双耳术语，我们将其定义为双耳对比度：耳间差异的好处。这样，SRM 就是单耳项和双耳项的简单总和。我们使用该框架对 10 名听力正常的听众的这些空间效应进行了量化。参与者在不同的空间设置中执行语音清晰度任务。我们使用与头部相关的传递函数来操纵耳间时间和电平差异的存在。我们使用了三种频谱匹配的掩蔽器类型：固定语音加权噪声、竞争说话者以及用竞争说话者的宽带时间包络调制的语音加权噪声。结果：我们发现（1）无论掩蔽器类型如何，双耳对比度都会因耳间时间差异而增加，但会因耳间声压级差异而降低；（2）大冗余（两耳具有相同信息的好处）会降低双耳对比度，从而也降低 SRM。结论：我们的框架对语音清晰度的双耳处理产生了新的见解。首先，耳间电平差异会干扰现实聆听条件下的语音清晰度。因此，为了优化助听器的语音清晰度，提高单耳信噪比比保持耳间电平差异更有利。其次，虽然在考虑空间听觉时冗余大多被忽略，但它可能解释在某些情况下 SRM 的减少。
Objectives: To establish a framework to unambiguously define and relate the different spatial effects in speech understanding: head shadow, redundancy, squelch, spatial release from masking (SRM), and so on. Next, to investigate the contribution of interaural time and level differences to these spatial effects in speech understanding and how this is influenced by the type of masking noise. Design: In our framework, SRM is uniquely characterized as a linear combination of head shadow, binaural redundancy, and binaural squelch. The latter two terms are combined into one binaural term, which we define as binaural contrast: a benefit of interaural differences. In this way, SRM is a simple sum of a monaural and a binaural term. We used the framework to quantify these spatial effects in 10 listeners with normal hearing. The participants performed speech intelligibility tasks in different spatial setups. We used head-related transfer functions to manipulate the presence of interaural time and level differences. We used three spectrally matched masker types: stationary speech-weighted noise, a competing talker, and speech-weighted noise that was modulated with the broadband temporal envelope of the competing talker. Results: We found that (1) binaural contrast was increased by interaural time differences, but reduced by interaural level differences, irrespective of masker type, and (2) large redundancy (the benefit of having identical information in two ears) could reduce binaural contrast and thus also reduce SRM. Conclusions: Our framework yielded new insights in binaural processing in speech intelligibility. First, interaural level differences disturb speech intelligibility in realistic listening conditions. Therefore, to optimize speech intelligibility in hearing aids, it is more beneficial to improve monaural signal-to-noise ratios rather than to preserve interaural level differences. Second, although redundancy is mostly ignored when considering spatial hearing, it might explain reduced SRM in some cases.