The Effects of Aging and Interaural Delay on the Detection of a Break in the Interaural Correlation between Two Sounds
The Effects of Aging and Interaural Delay on the Detection of a Break in the Interaural Correlation between Two Sounds
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衰老和耳间延迟对检测两个声音之间耳间相关性中断的影响
DOI：
10.1097/aud.0b013e318198703d
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发表时间：
2009-04-01
期刊：
影响因子：
3.7
通讯作者：
Schneider, Bruce A.
中科院分区：
文献类型：
--
作者：
Li, Liang;Huang, Juan;Schneider, Bruce A.
目标：在嘈杂、混响的环境中，老年人常常发现很难处理声信号，这可能是因为他们区分属于某个源的反射波和其他源产生的反射波的能力随着年龄的增长而减弱。因此，老年人将听觉场景解析为其组成声源的效率可能低于年轻人。为了将听觉场景解析为其组成源，听众必须能够对来自不同方向的相关波（直达波及其从环境表面的反射）进行分组。由于检测相关性变化是场景解析的重要组成部分，因此本研究检查了在检测左右耳机或左右扬声器上呈现的噪声之间是否存在与年龄相关的相关性中断 (BIG) 缺陷，其中 BIC 指的是耳间相关性从 1 到 0，然后返回到 1 的变化。 设计：在实验 1 中，我们确定了 10 时的最短 BIC 持续时间。 年轻人和 10 名老年人可以在相同的噪音（带宽 = 10 kHz；持续时间 = 1 秒）中间检测到 BIC，这些噪音通过耳机同时呈现在左耳和右耳上，或者通过位于听众左右 45 度的扬声器同时播放。在实验 2 中，我们确定了左侧噪声和右侧噪声之间的最长延迟，在该延迟下，可以在 10 名年轻人和 8 名老年人中检测到出现在噪声中间的 100 毫秒 BIC。 结果：实验 1 的结果表明，年轻参与者可以检测到比年长参与者明显更短的 BIC，无论噪声是通过耳机还是扬声器呈现。实验 2 的结果表明，年轻的参与者可以比年长的参与者以明显更长的耳间延迟检测到 100 ms BIC。此外，对于两个年龄组来说，在扬声器刺激条件下检测 BIC 比在耳机刺激条件下更容易。此外，在扬声器条件下，相关声源之间相互作用产生的频谱线索似乎对年轻人比年长参与者更有利。结论：与年龄相关的 BIC 敏感性下降表明，老年人比年轻人更难检测到持续声音中相关性的变化。当到达一只耳朵的噪声相对于到达另一只耳朵的噪声延迟时，老年人无法像年轻人一样容易地检测到 100 ms BIC，这表明老年人的声音波形表征比年轻的成年听众衰减得更快。此外，这些与年龄相关的缺陷与听众的听力图无关。此外，当扬声器上呈现的噪声之间存在延迟时，年轻人似乎比老年人更擅长使用梳状滤波提供的频谱线索来检测 BIC。波形细节的衰减越快，加上对相关性变化和频谱线索的敏感性较低，表明老年人在解析听觉场景方面可能不如年轻人那么有能力。
Objectives: In noisy, reverberant environments, older adults often find it difficult to process acoustic signals, possibly because their ability to differentiate reflected waves that belong to a source from those generated by other sources diminishes with age. Therefore, older adults may be less efficient than younger adults at parsing the auditory scene into its component sound sources. To parse the auditory scene into its component sources the listener has to be able to group correlated waves coming from different directions (the direct wave and its reflections off of environmental surfaces). Because detecting a change in correlation is an important component of scene parsing, this study examined whether there is an age-related deficit in detecting break in correlation (BIG) between the noises presented over left and right headphones or over left and right loudspeakers, where a BIC refers to a change in interaural correlation from 1 to zero and then a return to 1.Design: In experiment 1, we determined the shortest BIC duration at which 10 younger and 10 older adults could detect the BIC in the middle of identical noises (bandwidth = 10 kHz; duration = 1 sec) presented simultaneously to the left and right ears over headphones or played simultaneously over loudspeakers positioned 45 degrees to the left and right of the listeners. In experiment 2, we determined the longest delay between the left-side noise and the right-side noise, at which a 100 ms BIC presented in the middle of the noise could be detected in 10 younger and 8 older adults.Results: The results of experiment 1 show that younger participants could detect significantly shorter BICs than older participants independent of whether the noises were presented over headphones or loudspeakers. The results of experiment 2 show that younger participants could detect the 100 ms BIC at significantly longer interaural delays than older participants. Also, for both age groups, detecting the BIC was easier under the loudspeaker-stimulation condition than the head phone-stimulation condition. Moreover, in the loudspeaker condition, the spectral cues arising from interactions between correlated sound sources seemed to be of greater benefit to younger than to older participants.Conclusions: The age-related decrease in sensitivity to a BIC indicates that older adults are less able than younger adults to detect a change in correlation in an ongoing sound. The inability of older adults to detect the 100 ms BIC as readily as younger adults, when the noise arriving at one ear is delayed relative to the noise arriving at the other ear, suggests that the representation of aspects of the sound's waveform decays more rapidly in older adult than in younger adult listeners. Moreover, these age-related deficits are not related to listeners' audiograms. In addition, younger adults seem to be much better than older adults at using the spectral cue provided by comb filtering to detect the BIC when there is a delay between the noises presented over loudspeakers, The more rapid decay of waveform details, combined with the lesser sensitivity to change in correlation and to spectral cues, suggest that older adults may not be as capable as younger adults in parsing auditory scenes.