1 Department of Experimental Psychology, University of Cambridge, England.
2 Faculty of Physics, Institute of Acoustics, Adam Mickiewicz University, Poznań, Poland.
Trends Hear. 2019 Jan-Dec;23:2331216519853963. doi: 10.1177/2331216519853963.
Detection of frequency modulation (FM) with rate = 10 Hz may depend on conversion of FM to amplitude modulation (AM) in the cochlea, while detection of 2-Hz FM may depend on the use of temporal fine structure (TFS) information. TFS processing may worsen with greater age and hearing loss while AM processing probably does not. A two-stage experiment was conducted to test these ideas while controlling for the effects of detection efficiency. Stage 1 measured psychometric functions for the detection of AM alone and FM alone imposed on a 1-kHz carrier, using 2- and 10-Hz rates. Stage 2 assessed the discrimination of AM from FM at the same modulation rate when the detectability of the AM alone and FM alone was equated. Discrimination was better for the 2-Hz than for the 10-Hz rate for all young normal-hearing subjects and for some older subjects with normal hearing at 1 kHz. Other older subjects with normal hearing showed no clear difference in AM-FM discrimination for the 2- and 10-Hz rates, as was the case for most older hearing-impaired subjects. The results suggest that the ability to use TFS cues is reduced for some older people and most hearing-impaired people.
检测频率调制（FM）的频率为 10 Hz 可能取决于在耳蜗中将 FM 转换为幅度调制（AM），而检测 2 Hz 的 FM 可能取决于使用时间精细结构（TFS）信息。TFS 处理可能会随着年龄和听力损失的增加而恶化，而 AM 处理可能不会。进行了一个两阶段实验来测试这些想法，同时控制检测效率的影响。第 1 阶段测量了仅施加在 1 kHz 载波上的 AM 和 FM 的检测的心理物理函数，使用了 2 Hz 和 10 Hz 的速率。第 2 阶段评估了在单独检测 AM 和 FM 的可检测性相同时 AM 与 FM 的辨别能力。对于所有年轻的正常听力受试者和一些在 1 kHz 时具有正常听力的年长受试者，2 Hz 的辨别能力优于 10 Hz 的辨别能力。其他具有正常听力的年长受试者在 2 Hz 和 10 Hz 之间的 AM-FM 辨别力方面没有明显差异，大多数老年听力受损受试者也是如此。结果表明，一些老年人和大多数听力受损者使用 TFS 线索的能力降低。
