Department of Auditory Implantation, Shandong Provincial ENT Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, People's Republic of China.
Heuser Hearing Research Center, Louisville, Kentucky, USA.
Ear Hear. 2022;43(4):1139-1150. doi: 10.1097/AUD.0000000000001173. Epub 2021 Nov 12.
The primary goal of this study was to investigate the effects of reverberation on Mandarin tone and vowel recognition of cochlear implant (CI) users and normal-hearing (NH) listeners. To understand the performance of Mandarin tone recognition, this study also measured participants' pitch perception and the availability of temporal envelope cues in reverberation.
Fifteen CI users and nine NH listeners, all Mandarin speakers, were asked to recognize Mandarin single-vowels produced in four lexical tones and rank harmonic complex tones in pitch with different reverberation times (RTs) from 0 to 1 second. Virtual acoustic techniques were used to simulate rooms with different degrees of reverberation. Vowel duration and correlation between amplitude envelope and fundamental frequency (F0) contour were analyzed for different tones as a function of the RT.
Vowel durations of different tones significantly increased with longer RTs. Amplitude-F0 correlation remained similar for the falling Tone 4 but greatly decreased for the other tones in reverberation. NH listeners had robust pitch-ranking, tone recognition, and vowel recognition performance as the RT increased. Reverberation significantly degraded CI users' pitch-ranking thresholds but did not significantly affect the overall scores of tone and vowel recognition with CIs. Detailed analyses of tone confusion matrices showed that CI users reduced the flat Tone-1 responses but increased the falling Tone-4 responses in reverberation, possibly due to the falling amplitude envelope of late reflections after the original vowel segment. CI users' tone recognition scores were not correlated with their pitch-ranking thresholds.
NH listeners can reliably recognize Mandarin tones in reverberation using salient pitch cues from spectral and temporal fine structures. However, CI users have poorer pitch perception using F0-related amplitude modulations that are reduced in reverberation. Reverberation distorts speech amplitude envelopes, which affect the distribution of tone responses but not the accuracy of tone recognition with CIs. Recognition of vowels with stationary formant trajectories is not affected by reverberation for both NH listeners and CI users, regardless of the available spectral resolution. Future studies should test how the relatively stable vowel and tone recognition may contribute to sentence recognition in reverberation of Mandarin-speaking CI users.
本研究的主要目的是探究混响对人工耳蜗（CI）使用者和正常听力（NH）者识别普通话声调及元音的影响。为了理解普通话声调识别的表现，本研究还测量了参与者在混响中的音高感知和时域包络线索的可用性。
本研究共纳入 15 名 CI 使用者和 9 名 NH 者，所有参与者均为汉语普通话使用者，要求其识别在四个词调下产生的普通话单音节，并对具有不同混响时间（0 到 1 秒）的谐波复合音进行音高排序。使用虚拟声学技术模拟不同混响程度的房间。分析不同声调下的元音时长以及幅度包络和基频（F0）轮廓之间的相关性，作为 RT 的函数。
不同声调的元音时长随着 RT 的延长而显著增加。在混响中，下降调 4 的幅度-F0 相关性保持相似，但其他声调的相关性则显著降低。随着 RT 的增加，NH 者的音高排序、声调识别和元音识别性能均稳健。混响显著降低了 CI 使用者的音高排序阈值，但并未显著影响 CI 使用者的整体声调及元音识别得分。声调混淆矩阵的详细分析表明，CI 使用者在混响中减少了平调 1 的反应，但增加了下降调 4 的反应，这可能是由于原始元音段后的后期反射具有下降的幅度包络。CI 使用者的声调识别得分与他们的音高排序阈值无关。
NH 者可以使用来自频谱和时域精细结构的显著音高线索，在混响中可靠地识别普通话声调。然而，CI 使用者使用的与 F0 相关的幅度调制的音高感知较差，而这种调制在混响中会被削弱。混响会扭曲语音幅度包络，影响声调反应的分布，但不会影响 CI 使用者的声调识别准确性。对于 NH 者和 CI 使用者来说，具有固定共振峰轨迹的元音的识别不受混响影响，而与频谱分辨率无关。未来的研究应检验相对稳定的元音和声调识别如何有助于汉语普通话 CI 使用者在混响中的句子识别。
