Sutojo Sarinah, van de Par Steven, Schoenmaker Esther
Acoustics Group, Cluster of Excellence Hearing4all, Carl von Ossietzky University, Oldenburg, Germany.
Eur J Neurosci. 2020 Mar;51(5):1339-1352. doi: 10.1111/ejn.13980. Epub 2018 Jul 26.
In situations with competing talkers or in the presence of masking noise, speech intelligibility can be improved by spatially separating the target speaker from the interferers. This advantage is generally referred to as spatial release from masking, and different mechanisms have been suggested to explain it. One proposed mechanism to benefit from spatial cues is the binaural masking release, which is purely stimulus-driven. According to this mechanism, the spatial benefit results from differences in the binaural cues of target and masker, which need to appear simultaneously in time and frequency to improve the signal detection. In an alternative proposed mechanism, the differences in the interaural cues improve the segregation of auditory streams, a process, which involves top-down processing rather than being purely stimulus-driven. Other than the cues that produce binaural masking release, the interaural cue differences between target and interferer required to improve stream segregation do not have to appear simultaneously in time and frequency. This study is concerned with the contribution of binaural masking release to spatial release from masking for three masker types that differ with respect to the amount of energetic masking they exert. Speech intelligibility was measured, employing a stimulus manipulation that inhibits binaural masking release and analysed with a metric to account for the number of better-ear glimpses. Results indicate that the contribution of the stimulus-driven binaural masking release plays a minor role while binaural stream segregation and the availability of glimpses in the better ear had a stronger influence on improving the speech intelligibility.
在存在多个说话者竞争或存在掩蔽噪声的情况下，通过将目标说话者与干扰源在空间上分离，可以提高语音可懂度。这种优势通常被称为空间掩蔽释放，并且已经提出了不同的机制来解释它。一种从空间线索中获益的提议机制是双耳掩蔽释放，这纯粹是由刺激驱动的。根据这一机制，空间优势源于目标和掩蔽声的双耳线索差异，这些差异需要在时间和频率上同时出现，以改善信号检测。在另一种提议机制中，双耳线索的差异改善了听觉流的分离，这一过程涉及自上而下的处理，而不是纯粹由刺激驱动。除了产生双耳掩蔽释放的线索外，改善流分离所需的目标与干扰源之间的双耳线索差异不必在时间和频率上同时出现。本研究关注的是双耳掩蔽释放在三种不同类型掩蔽源的空间掩蔽释放中的作用，这三种掩蔽源在它们施加的能量掩蔽量方面有所不同。通过一种抑制双耳掩蔽释放的刺激操作来测量语音可懂度，并使用一种考虑较好耳瞥见次数的指标进行分析。结果表明，由刺激驱动的双耳掩蔽释放在提高语音可懂度方面所起的作用较小，而双耳流分离以及较好耳中瞥见的可用性对提高语音可懂度有更强的影响。
