Using Spectral Blurring to Assess Effects of Channel Interaction on Speech-in-Noise Perception with Cochlear Implants
Using Spectral Blurring to Assess Effects of Channel Interaction on Speech-in-Noise Perception with Cochlear Implants
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DOI：
10.1007/s10162-020-00758-z
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发表时间：
2020-06-09
影响因子：
2.4
通讯作者：
Carlyon, Robert P.
中科院分区：
文献类型：
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作者：
Goehring, Tobias;Arenberg, Julie G.;Carlyon, Robert P.
人工耳蜗（CI）听者很难理解背景噪音中的语音。由于电流扩散，电极通道之间的相互作用增加了噪声对语音的掩盖，导致语音感知困难。因此，减少通道相互作用的策略有可能改善CI听众对噪声中的语音感知，但之前的结果好坏参半。在一项针对12名有经验的CI使用者的听力研究中，我们研究了通道相互作用对噪声中语音感知的影响及其与光谱-时间敏锐度的关系。我们没有试图减少通道相互作用，而是引入了光谱模糊来模拟通道相互作用的一些影响，通过调整分析滤波器输入电平电极通道之间的重叠，或者通过使用每个通道同时受激的几个电极来调节输出电平。我们测量了噪声中的语音接收阈值，作为应用于所有15个电极通道或5个均匀间隔通道的模糊量的函数。当应用于所有通道的模糊量增加到某个拐点时，性能保持大致不变，超过该拐点则会恶化。这个膝点在听众之间的差异与非言语频谱-时间任务的表现有关，在这里被提议作为通道交互的个人测量。令人惊讶的是，即使在5个通道上应用极端数量的模糊也不会影响性能。在CI的输入和输出处模糊对噪声中语音感知的影响是相似的。结果与以下假设一致：有经验的CI用户可以利用有限数量的有效信息渠道，并在识别有面具的语音时容忍与日常设置的一些偏差。此外，这些发现可能解释了优化或停用沿阵列均匀分布的少量电极的策略的混合结果，表明模糊或停用三分之一的电极并不会损害语音在噪声中的表现。
Cochlear implant (CI) listeners struggle to understand speech in background noise. Interactions between electrode channels due to current spread increase the masking of speech by noise and lead to difficulties with speech perception. Strategies that reduce channel interaction therefore have the potential to improve speech-in-noise perception by CI listeners, but previous results have been mixed. We investigated the effects of channel interaction on speech-in-noise perception and its association with spectro-temporal acuity in a listening study with 12 experienced CI users. Instead of attempting to reduce channel interaction, we introduced spectral blurring to simulate some of the effects of channel interaction by adjusting the overlap between electrode channels at the input level of the analysis filters or at the output by using several simultaneously stimulated electrodes per channel. We measured speech reception thresholds in noise as a function of the amount of blurring applied to either all 15 electrode channels or to 5 evenly spaced channels. Performance remained roughly constant as the amount of blurring applied to all channels increased up to some knee point, above which it deteriorated. This knee point differed across listeners in a way that correlated with performance on a non-speech spectro-temporal task, and is proposed here as an individual measure of channel interaction. Surprisingly, even extreme amounts of blurring applied to 5 channels did not affect performance. The effects on speech perception in noise were similar for blurring at the input and at the output of the CI. The results are in line with the assumption that experienced CI users can make use of a limited number of effective channels of information and tolerate some deviations from their everyday settings when identifying speech in the presence of a masker. Furthermore, these findings may explain the mixed results by strategies that optimized or deactivated a small number of electrodes evenly distributed along the array by showing that blurring or deactivating one-third of the electrodes did not harm speech-in-noise performance.