An Alternative Explanation for Difficulties with Speech in Background Talkers: Abnormal Fusion of Vowels Across Fundamental Frequency and Ears.
An Alternative Explanation for Difficulties with Speech in Background Talkers: Abnormal Fusion of Vowels Across Fundamental Frequency and Ears.
复制标题
对背景说话者语音困难的另一种解释：基本频率和耳朵中元音的异常融合。
DOI：
10.1007/s10162-021-00790-7
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Molis,MichelleR
中科院分区：
文献类型：
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作者：
Reiss,LinaAJ;Molis,MichelleR
听力正常 (NH) 的听众使用频率提示（例如基频（音调））将声音分成离散的听觉流。然而，许多听力障碍 (HI) 个体具有异常广泛的双耳音调融合，这导致原始单耳音调融合并平均到同一流中，而不是分离两个流（Oh 和 Reiss，2017），并且可能类似地导致跨耳语音流的融合和平均。在这项研究中，我们使用二分语音刺激来研究语音融合和元音识别之间的关系。在 NH 和 HI 听众中测量了双元音感知，跨耳基频差异各不相同。合成元音 /i/、/u/、/a/ 和 /ae/ 使用 106.9、151.2 和 201.8 Hz 三个基频 (F0) 生成，并通过耳机以二分音方式呈现。对于 HI 听众来说，刺激是根据 NAL-NL2 规定目标制定的。尽管双耳呈现的双元音总是不同的，但听众并没有被告知没有单一元音试验并且可以在每次试验中识别一个元音或两个不同的元音。当两耳之间没有 F0 差异时，NH 和 HI 听众更有可能融合元音并仅识别一个元音。随着 ΔF0 的增加，NH 听众增加了双元音反应的百分比，但 HI 听众更有可能继续融合元音，即使 ΔF0 很大。 NH 和 HI 听者的双耳音调融合范围与元音融合率显着相关。双元音的混淆模式与并发单耳元音的混淆模式不同，这表明错误背后的机制不同。总之，研究结果表明，广泛的融合会导致耳朵之间的频谱混合，即使对于不同的 ΔF0 也是如此，并且可能会阻碍在竞争说话者存在的情况下的流分离和语音理解。
Normal-hearing (NH) listeners use frequency cues, such as fundamental frequency (voice pitch), to segregate sounds into discrete auditory streams. However, many hearing-impaired (HI) individuals have abnormally broad binaural pitch fusion which leads to fusion and averaging of the original monaural pitches into the same stream instead of segregating the two streams (Oh and Reiss, 2017) and may similarly lead to fusion and averaging of speech streams across ears. In this study, using dichotic speech stimuli, we examined the relationship between speech fusion and vowel identification. Dichotic vowel perception was measured in NH and HI listeners, with across-ear fundamental frequency differences varied. Synthetic vowels /i/, /u/, /a/, and /ae/ were generated with three fundamental frequencies (F0) of 106.9, 151.2, and 201.8 Hz and presented dichotically through headphones. For HI listeners, stimuli were shaped according to NAL-NL2 prescriptive targets. Although the dichotic vowels presented were always different across ears, listeners were not informed that there were no single vowel trials and could identify one vowel or two different vowels on each trial. When there was noF0difference between the ears, both NH and HI listeners were more likely to fuse the vowels and identify only one vowel. As ΔF0increased, NH listeners increased the percentage of two-vowel responses, but HI listeners were more likely to continue to fuse vowels even with large ΔF0. Binaural tone fusion range was significantly correlated with vowel fusion rates in both NH and HI listeners. Confusion patterns with dichotic vowels differed from those seen with concurrent monaural vowels, suggesting different mechanisms behind the errors. Together, the findings suggest that broad fusion leads to spectral blending across ears, even for different ΔF0, and may hinder the stream segregation and understanding of speech in the presence of competing talkers.