Institute of Ecology and Evolution, Russian Academy of Sciences. 33 Leninsky Prospect, 119071 Moscow, Russia.
J Acoust Soc Am. 2011 Jul;130(1):574-84. doi: 10.1121/1.3596470.
In Yangtze finless porpoises Neophocaena phocaenoides asiaeorientalis, the effects of fatiguing noise on hearing thresholds at frequencies of 32, 45, 64, and 128 kHz were investigated. The noise parameters were: 0.5-oct bandwidth, -1 to +0.5 oct relative to the test frequency, 150 dB re 1 μPa (140-160 dB re 1 μPa in one measurement series), with 1-30 min exposure time. Thresholds were evaluated using the evoked-potential technique allowing the tracing of threshold variations with a temporal resolution better than 1 min. The most effective fatiguing noise was centered at 0.5 octave below the test frequency. The temporary threshold shift (TTS) depended on the frequencies of the fatiguing noise and test signal: The lower the frequencies, the bigger the noise effect. The time-to-level trade of the noise effect was incomplete: the change of noise level by 20 dB resulted in a change of TTS level by nearly 20 dB, whereas the tenfold change of noise duration resulted in a TTS increase by 3.8-5.8 dB.
在长江江豚（Neophocaena phocaenoides asiaeorientalis）中，研究了疲劳噪声对 32、45、64 和 128 kHz 频率下听力阈值的影响。噪声参数为：0.5 倍频带宽，相对于测试频率为-1 至+0.5 倍频，150 dB 相对 1 μPa（在一个测量系列中为 140-160 dB 相对 1 μPa），暴露时间为 1-30 分钟。使用诱发电位技术评估阈值，允许以优于 1 分钟的时间分辨率跟踪阈值变化。最有效的疲劳噪声集中在测试频率下方 0.5 倍频程处。暂时阈移（TTS）取决于疲劳噪声和测试信号的频率：频率越低，噪声的影响越大。噪声效应的时间-水平交换不完全：噪声水平变化 20 dB 导致 TTS 水平变化近 20 dB，而噪声持续时间增加十倍导致 TTS 增加 3.8-5.8 dB。
