Department of Psychology, University of Cambridge, Downing Street, Cambridge CB2 3EB, United Kingdom.
Audiology Group, Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Tungasletta 2, Trondheim 7491, Norway.
J Acoust Soc Am. 2019 Aug;146(2):1207. doi: 10.1121/1.5122794.
The ability to discriminate irregular from regular amplitude modulation was compared for young and older adults with audiometric thresholds within the normal range for frequencies from 250 to 8000 Hz, using the "envelope regularity discrimination" (ERD) test. The amount of irregularity was parametrically varied and quantified by an "irregularity index." The carrier frequency was 2000 Hz, the modulation rate was 8 Hz, and the baseline modulation index was 0.3. Stimuli were presented both at 80 dB sound pressure level (SPL) and at 20 dB sensation level (SL) in the presence of a threshold-equalizing noise. There was a significant effect of level, performance being better at 80 dB SPL than at 20 dB SL. There was also a significant effect of age, performance being worse for the older subjects. There was no significant interaction of level and age. The thresholds for the ERD test were not significantly correlated with absolute thresholds at the test carrier frequency of 2000 Hz, for either group, or for the two groups combined. The worse envelope regularity discrimination for the older group may be related to the age-related synaptopathy that has been established from recent studies of human temporal bones.
使用“包络规则辨别”（ERD）测试比较了听力阈值在正常范围内（频率为 250 至 8000 Hz）的年轻人和老年人辨别不规则幅度调制与规则幅度调制的能力。通过“不规则指数”对不规则量进行参数变化和量化。载波频率为 2000 Hz，调制率为 8 Hz，基线调制指数为 0.3。在阈等噪声存在的情况下，以 80 dB 声压级（SPL）和 20 dB 感觉级（SL）呈现刺激。存在显著的水平效应，在 80 dB SPL 下的表现优于在 20 dB SL 下的表现。年龄也有显著的影响，老年人的表现更差。水平和年龄之间没有显著的交互作用。对于 ERD 测试，无论是对于年轻人还是老年人，或者是两个年龄组的组合，其阈值与测试载波频率 2000 Hz 的绝对阈值均无显著相关性。对于老年人来说，较差的包络规则辨别能力可能与最近对人类颞骨的研究中已经确定的与年龄相关的突触病有关。
