Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users.
Discrimination of Stochastic Frequency Modulation by Cochlear Implant Users.
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DOI：
10.3766/jaaa.14067
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发表时间：
2015-06
影响因子：
1.2
通讯作者：
Shafiro V
中科院分区：
文献类型：
--
作者：
Sheft S;Cheng MY;Shafiro V
过去的工作表明，低速率频率调制 (FM) 可能有助于保持信号一致性，有助于在单词和音节边界处进行分割，并有利于在存在掩蔽器的情况下提高语音清晰度。本研究评估了人工耳蜗 (CI) 用户的言语感知困难是否与辨别随机低速率 FM 模式的能力缺陷有关。这是一项相关研究，评估区分低速率 FM 随机模式的能力与噪声中语音清晰度之间的关联。 13 名语后聋的成年 CI 用户参与了这项研究。使用源自应用于 1kHz 载波的 5Hz 低通噪声的调制器，根据频率偏移（在无噪声和存在语音混音掩蔽器的情况下）、刺激持续时间和存在语音混音掩蔽器的情况下的信噪比来测量阈值。在存在相同的言语掩蔽器的情况下评估言语感知能力。通过皮尔逊积矩相关分析（纠正家庭误差）和共性分析来评估关系，以确定心理声学变量对言语能力关联的独特和共同贡献。掩蔽语音清晰度与涉及信噪比或刺激持续时间的三个 FM 辨别指标之间存在显着相关性，这三个指标之间的共同方差在很大程度上解释了这种影响。与过去的听力正常的年轻人和听力正常或轻度至中度听力损失的老年人的结果相比，从 CI 用户获得的平均 FM 辨别阈值在所有条件下都较高。处理随机调频频率偏移模式的能力可能部分地与噪声中的语音感知具有共同基础。对刺激的时间分布位置编码差异的区分可以作为 CI 用户的共同基础。
Past work has shown that low-rate frequency modulation (FM) may help preserve signal coherence, aid segmentation at word and syllable boundaries, and benefit speech intelligibility in the presence of a masker. This study evaluated whether difficulties in speech perception by cochlear implant (CI) users relate to a deficit in the ability to discriminate among stochastic low-rate patterns of FM. This is a correlational study assessing the association between the ability to discriminate stochastic patterns of low-rate FM and the intelligibility of speech in noise. Thirteen postlingually deafened adult CI users participated in this study. Using modulators derived from 5-Hz lowpass noise applied to a 1-kHz carrier, thresholds were measured in terms of frequency excursion both inquiet and with a speech-babble masker present, stimulus duration, and signal-to-noise ratio in the presence of a speech-babble masker. Speech perception ability was assessed in the presence of the same speech-babble masker. Relationships were evaluated with Pearson product–moment correlation analysis with correction for family-wise error, and commonality analysis to determine the unique and common contributions across psychoacoustic variables to the association with speech ability. Significant correlations were obtained between masked speech intelligibility and three metrics of FM discrimination involving either signal-to-noise ratio or stimulus duration, with shared variance among the three measures accounting for much of the effect. Compared to past results from young normal-hearing adults and older adults with either normal hearing or a mild-to-moderate hearing loss, mean FM discrimination thresholds obtained from CI users were higher in all conditions. The ability to process the pattern of frequency excursions of stochastic FM may, in part, have a common basis with speech perception in noise. Discrimination of differences in the temporally distributed place coding of the stimulus could serve as this common basis for CI users.