Processing of temporal fine structure as a function of age.
Processing of temporal fine structure as a function of age.
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DOI：
10.1097/aud.0b013e3181e627e7
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发表时间：
2010-12
期刊：
影响因子：
3.7
通讯作者：
Mamo SK
中科院分区：
文献类型：
--
作者：
Grose JH;Mamo SK
本研究的目的是确定是否处理的时间精细结构随着年龄的增长而减少，即使在存在相对正常的听力。时间精细结构处理通过测量双耳相位差（IPD）的区分度进行评估。该假设是，IPD歧视是更严重的中年观察员比老年观察员，但在中年观察员的敏锐度仍然比年轻人差。进行了两个实验。作为载波频率的函数的0和π弧度耳间相位的第一测量辨别。刺激是一个5赫兹正弦振幅调制的音调，其中，在信号波形中，在交替调制期间，载波的耳间相位被反转。第二个实验测量固定频率下的IPD辨别力。刺激是一对音调脉冲，其中，在信号中，拖尾脉冲包含IPD。共有39名听力正常的成年人参加了这项研究：15名年轻人，12名中年人和12名老年人。实验1表明，π弧度IPD可以从diotic，0弧度标准中区分出来的最高载波频率在中年听众中明显低于年轻人，在老年听众中更低。实验2表明，中年听众不太敏感的IPD比年轻的成年人在所有，但测试的最低频率。年长的听众作为一个群体，他们的阈值最低。这些结果表明，赤字的时间精细结构处理是明显的，在衰老前的听觉系统。这增加了越来越多的证据表明，在听觉时间处理的某些方面的缺陷出现在衰老过程中相对较早。早期出现的时间处理缺陷可能在具有挑战性的噪声环境中表现出来。
The purpose of this study was to determine whether the processing of temporal fine structure diminishes with age, even in the presence of relatively normal audiometric hearing. Temporal fine structure processing was assessed by measuring the discrimination of inter-aural phase differences (IPDs). The hypothesis was that IPD discrimination is more acute in middle-aged observers than in older observers but that acuity in middle-aged observers is nevertheless poorer than in young adults. Two experiments were undertaken. The first measured discrimination of 0-and π-radian inter-aural phases as a function of carrier frequency. The stimulus was a 5-Hz sinusoidally amplitude modulated tone where, in the signal waveform, the inter-aural phase of the carrier was inverted during alternate modulation periods. The second experiment measured IPD discrimination at fixed frequencies. The stimulus was a pair of tone pulses where, in the signal, the trailing pulse contained an IPD. A total of 39 adults with normal audiograms below 2000 Hz participated: 15 younger, 12 middle-aged, and 12 older. Experiment 1 showed that the highest carrier frequency at which a π-radian IPD could be discriminated from the diotic, 0-radian standard was significantly lower in middle-aged listeners than young adults, and lower still in older listeners. Experiment 2 indicated that middle-aged listeners were less sensitive to IPDs than young adults at all but the lowest frequencies tested. Older listeners, as a group, had the poorest thresholds. These results suggest that deficits in temporal fine structure processing are evident in the pre-senescent auditory system. This adds to the accumulating evidence that deficiencies in some aspects of auditory temporal processing emerge relatively early in the aging process. It is possible that early-emerging temporal processing deficits manifest themselves in challenging speech-in-noise environments.