Noise adaptation is the improvement in auditory function as the signal of interest is delayed in the noise. Here, we investigated if noise adaptation occurs in spectral, temporal, and spectrotemporal modulation detection as well as in speech recognition. Eighteen normal-hearing adults participated in the experiments. In the modulation detection tasks, the signal was a 200ms spectrally and/or temporally modulated ripple noise. The spectral modulation rate was two cycles per octave, the temporal modulation rate was 10 Hz, and the spectrotemporal modulations combined these two modulations, which resulted in a downward-moving ripple. A control experiment was performed to determine if the results generalized to upward-moving ripples. In the speech recognition task, the signal consisted of disyllabic words unprocessed or vocoded to maintain only envelope cues. Modulation detection thresholds at 0 dB signal-to-noise ratio and speech reception thresholds were measured in quiet and in white noise (at 60 dB SPL) for noise-signal onset delays of 50 ms (early condition) and 800 ms (late condition). Adaptation was calculated as the threshold difference between the early and late conditions. Adaptation in word recognition was statistically significant for vocoded words (2.1 dB) but not for natural words (0.6 dB). Adaptation was found to be statistically significant in spectral (2.1 dB) and temporal (2.2 dB) modulation detection but not in spectrotemporal modulation detection (downward ripple: 0.0 dB, upward ripple: −0.4 dB). Findings suggest that noise adaptation in speech recognition is unrelated to improvements in the encoding of spectrotemporal modulation cues.

中文翻译：

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谱时调制检测和单词识别中的噪声适应


噪声适应是听觉功能的改善，因为感兴趣的信号在噪声中被延迟。在这里，我们研究了噪声适应是否发生在频谱、时间和频谱时间调制检测以及语音识别中。十八名听力正常的成年人参与了实验。在调制检测任务中，信号是 200ms 频谱和/或时间调制纹波噪声。频谱调制率为每倍频程两个周期，时间调制率为10 Hz，频谱时间调制结合了这两种调制，从而产生向下移动的纹波。进行了对照实验以确定结果是否推广到向上移动的波纹。在语音识别任务中，信号由未经处理或声编码的双音节单词组成，仅保留包络线索。 0 dB 信噪比下的调制检测阈值和语音接收阈值是在安静和白噪声（60 dB SPL）下测量的，噪声信号起始延迟为 50 ms（早期条件）和 800 ms（晚期条件） 。适应度计算为早期条件和晚期条件之间的阈值差异。单词识别的适应对于声码单词 (2.1 dB) 具有统计显着性，但对于自然单词 (0.6 dB) 则不显着。发现适应在频谱 (2.1 dB) 和时间 (2.2 dB) 调制检测中具有统计显着性，但在频谱时间调制检测中则不显着（向下纹波：0.0 dB，向上纹波：-0.4 dB）。研究结果表明，语音识别中的噪声适应与频谱时间调制线索编码的改进无关。