Discrimination of Voice Pitch and Vocal-Tract Length in Cochlear Implant Users.
Discrimination of Voice Pitch and Vocal-Tract Length in Cochlear Implant Users.
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DOI：
10.1097/aud.0000000000000480
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发表时间：
2018
期刊：
影响因子：
3.7
通讯作者：
Başkent D
中科院分区：
文献类型：
--
作者：
Gaudrain E;Başkent D
当听两个相互竞争的说话者说话时，听力正常的听众可以利用说话者之间的声音差异。人工耳蜗使用者在语音感知上有困难。先前的文献表明，植入体使用者对音高（与基频有关，F0）的敏感性较差，而对另一个主要语音特征——声道长度（VTL，与说话者的高度和共振峰频率有关）的敏感性在CIs中尚未得到直接研究。最近的一些研究通过语音性别分类间接评估了F0和VTL感知，这依赖于对两种语音线索的感知。这些研究表明，与先前的文献相反，CI用户似乎完全依赖于F0，而不使用VTL来执行此任务。本研究的目的是直接和系统地评估CI用户对F0和VTL差异的原始敏感性，以确定声音感知缺陷的程度。采用自适应三选项强制选择法，对11名CI听者的F0和VTL的刚显差异（JNDs）进行了测量。结果表明，NH听众F0和VTL的平均jnd分别为1.95和1.73半音（st）， CI听众的jnd分别为9.19和7.19 st， F0和VTL的jnd分别为70%和52%。与人群中声音的自然范围相比，CIs中的F0 JND仍然小于典型的男女F0差异。但是，ci中VTL的平均JND大约是典型的男女VTL差异的两倍。因此，这些发现直接证实了CI听者似乎没有足够的机会获得VTL线索，这可能是有限的频谱分辨率的结果，因此，CI听者的声音感知缺陷不仅仅是对F0的感知差。这些结果不仅为CI听众中观察到的一些缺陷（如语音识别和性别分类）提供了一个潜在的共同解释，而且还为竞争性语音感知提供了一个潜在的共同解释。
When listening to two competing speakers, normal-hearing (NH) listeners can take advantage of voice differences between the speakers. Users of cochlear implants (CIs) have difficulty in perceiving speech on speech. Previous literature has indicated sensitivity to voice pitch (related to fundamental frequency, F0) to be poor among implant users, while sensitivity to vocal-tract length (VTL; related to the height of the speaker and formant frequencies), the other principal voice characteristic, has not been directly investigated in CIs. A few recent studies evaluated F0 and VTL perception indirectly, through voice gender categorization, which relies on perception of both voice cues. These studies revealed that, contrary to prior literature, CI users seem to rely exclusively on F0 while not utilizing VTL to perform this task. The objective of the present study was to directly and systematically assess raw sensitivity to F0 and VTL differences in CI users to define the extent of the deficit in voice perception. The just-noticeable differences (JNDs) for F0 and VTL were measured in 11 CI listeners using triplets of consonant–vowel syllables in an adaptive three-alternative forced choice method. The results showed that while NH listeners had average JNDs of 1.95 and 1.73 semitones (st) for F0 and VTL, respectively, CI listeners showed JNDs of 9.19 and 7.19 st. These JNDs correspond to differences of 70% in F0 and 52% in VTL. For comparison to the natural range of voices in the population, the F0 JND in CIs remains smaller than the typical male–female F0 difference. However, the average VTL JND in CIs is about twice as large as the typical male–female VTL difference. These findings, thus, directly confirm that CI listeners do not seem to have sufficient access to VTL cues, likely as a result of limited spectral resolution, and, hence, that CI listeners’ voice perception deficit goes beyond poor perception of F0. These results provide a potential common explanation not only for a number of deficits observed in CI listeners, such as voice identification and gender categorization, but also for competing speech perception.