Shifting Fundamental Frequency in Simulated Electric-Acoustic Listening: Effects of F0 Variation.
Shifting Fundamental Frequency in Simulated Electric-Acoustic Listening: Effects of F0 Variation.
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DOI：
10.1097/aud.0000000000000227
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发表时间：
2016-01
期刊：
影响因子：
3.7
通讯作者：
Bacon SP
中科院分区：
文献类型：
--
作者：
Brown CA;Helms Tillery K;Apoux F;Doyle NM;Bacon SP
将目标语音的平均基频（F0）移到较低的频率，可能是一种为人工耳蜗（CI）用户提供电声刺激（EAS）好处的方法，这些用户的残余听力有限，即使有放大，通常也无法获得好处。然而，先前的研究表明，在最大的频率向下移动时，获益量下降，我们假设这可能与F0变化有关。因此，在当前的研究中，我们试图确定平均F0、F0变化与人工耳蜗电刺激与低频残余声听力相结合的益处之间的关系。我们使用EAS模拟测量了正常听力听众的语音清晰度，EAS模拟由正弦声码器与500 Hz的语音低通滤波器或代表目标F0的纯音相结合组成。我们利用提取的目标音高信息对音调进行调制，并对载波频率（平均F0）和音高信息的标准差（F0变化）进行操纵。在测试的最低平均F0处观察到EAS效益的下降，但当F0变化减少到与频率移位量成正比时（即当F0以对数而不是线性移位时），这种下降就消失了。通过移动携带目标语音音高信息的纯音的频率来降低平均F0可以提供与未移动的音调一样多的EAS好处，至少在当前的EAS模拟中是这样。这些结果可能对残余听觉极其有限的人工耳蜗使用者有启示意义。
Shifting the mean fundamental frequency (F0) of target speech down in frequency may be a way to provide the benefits of electric-acoustic stimulation (EAS) to cochlear implant (CI) users whose limited residual hearing precludes a benefit typically, even with amplification. However, previous work showed a decline in the amount of benefit at the greatest downward frequency shifts, and we hypothesized that this might be related to F0 variation. Thus, in the current study we sought to determine the relationship between mean F0, F0 variation, and the benefits of combining electric stimulation from a cochlear implant with low-frequency residual acoustic hearing. We measured speech intelligibility in normal-hearing listeners using an EAS simulation consisting of a sine vocoder combined either with speech low-pass filtered at 500 Hz, or with a pure tone representing target F0. We used extracted target voice pitch information to modulate the tone, and manipulated both the frequency of the carrier (mean F0), as well as the standard deviation of the voice pitch information (F0 variation). A decline in EAS benefit was observed at the lowest mean F0 tested, but this decline disappeared when F0 variation was reduced to be proportional to the amount of the shift in frequency (i.e., when F0 was shifted logarithmically instead of linearly). Lowering mean F0 by shifting the frequency of a pure tone carrying target voice pitch information can provide as much EAS benefit as an unshifted tone, at least in the current simulation of EAS. These results may have implications for cochlear implant users with extremely limited residual acoustic hearing.