Acoustic Cue Weighting by Adults with Cochlear Implants: A Mismatch Negativity Study.
Acoustic Cue Weighting by Adults with Cochlear Implants: A Mismatch Negativity Study.
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DOI：
10.1097/aud.0000000000000257
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发表时间：
2016-07
期刊：
影响因子：
3.7
通讯作者：
Shahin AJ
中科院分区：
文献类型：
--
作者：
Moberly AC;Bhat J;Shahin AJ
频率上升时间（FRT）和幅度上升时间（ART）是告知语音身份的声学线索。FRT表示共振峰到稳定状态的转变速率，而ART表示声音达到其峰值振幅的速率。在/Bα/-/wα/对比度的知觉标记过程中，听力正常（NH）的英语母语者对FRT的权重大于ART。这种加权策略在神经生理学上反映在失配负性（MMN）的幅度中- MMN在FRT期间大于ART区分。本研究采用MMN设计，探讨了成年人工耳蜗（CI）听者听觉线索加权的神经生理学基础。假设在行为标签中更重视ART的CI个体（ART用户）在ART期间显示的MMN比FRT对比期间更大，而FRT用户的情况则相反。20名CI患者在被动听三种合成语音刺激的组合时记录脑电图（EEG）：a /Bα/与/Bα/-like FRT和ART，a /wα/与/wα/-like FRT和ART，和a /Bα/wa刺激，具有/Bα/-类FRT和/wα/-类ART。在FRT对比期间，通过让被试被动地听一系列/wα/刺激偶尔被/Bα/wa刺激中断，反之亦然。对于ART对比，使用/Bα/和/Bα/wa刺激实施相同的程序。ART-和FRT-用户与CI引起的MMN是相等的幅度在FRT和ART对比，除了FRT-用户表现出MMN的ART和FRT对比，是暂时隔离。也就是说，他们的MMN在ART对比期间（声音开始后约100 ms）比在FRT对比期间（约200 ms）明显更早发生。相比之下，两种对比的ART用户的MMN发生较晚，并且在时间上没有显著分离（~230 ms）。有趣的是，在FRT用户中观察到的这种时间隔离与NH听众中的MMN行为一致。结果表明，与CI的听众谁学会分类音素的基础上共振峰的动态，与NH的听众一致，开发一种策略类似于NH的听众，在听觉记忆中的音素的振幅和频谱表示的组织时间隔离。
Formant Rise Time (FRT) and Amplitude Rise Time (ART) are acoustic cues that inform phonetic identity. FRT represents the rate of transition of the formant(s) to a steady state, while ART represents the rate at which the sound reaches its peak amplitude. Normal hearing (NH) native English speakers weight FRT more than ART during the perceptual labeling of the /bα/-/wα/ contrast. This weighting strategy is reflected neurophysiologically in the magnitude of the mismatch negativity (MMN) – MMN is larger during the FRT than the ART distinction. The present study examined the neurophysiological basis of acoustic cue weighting in adult cochlear implant (CI) listeners using the MMN design. It was hypothesized that individuals with CIs who weight ART more in behavioral labeling (ART-users) would show larger MMNs during the ART than the FRT contrast, and the opposite would be seen for FRT-users. Electroencephalography (EEG) was recorded while twenty adults with CIs listened passively to combinations of three synthetic speech stimuli: a /bα/ with /bα/-like FRT and ART; a /wα/ with /wα/-like FRT and ART; and a /bα/wa stimulus with /bα/-like FRT and /wα/-like ART. The MMN response was elicited during the FRT contrast by having participants passively listen to a train of /wα/ stimuli interrupted occasionally by /bα/wa stimuli, and vice versa. For the ART contrast, the same procedure was implemented using the /bα/ and /bα/wa stimuli. Both ART- and FRT-users with CIs elicited MMNs that were equal in magnitudes during FRT and ART contrasts, with the exception that FRT-users exhibited MMNs for ART and FRT contrasts that were temporally segregated. That is, their MMNs occurred significantly earlier during the ART contrast (~100 ms following sound onset) than during the FRT contrast (~200ms). In contrast, the MMNs for ART-users of both contrasts occurred later and were not significantly separable in time (~230 ms). Interestingly, this temporal segregation observed in FRT-users is consistent with the MMN behavior in NH listeners. Results suggest that listeners with CIs who learn to classify phonemes based on formant dynamics, consistent with NH listeners, develop a strategy similar to NH listeners, in which the organization of the amplitude and spectral representations of phonemes in auditory memory are temporally segregated.