Sommers M S, Humes L E
Speech Research Laboratory, Indiana University, Bloomington 47405.
J Acoust Soc Am. 1993 May;93(5):2903-14. doi: 10.1121/1.405810.
To dissociate the effects of age and hearing impairment on changes in frequency selectivity, auditory filter shapes were measured at 2 kHz in four groups of subjects: (1) normal-hearing young subjects; (2) normal-hearing elderly subjects; (3) elderly hearing-impaired listeners; and (4) young normal-hearing listeners with simulated hearing losses. Filter shapes were derived using a modified version of the notched-noise procedure [Glasberg and Moore, Hear, Res. 47, 103-138 (1990)]. Equivalent rectangular bandwidths (ERBs) of auditory filters were not significantly different in young and elderly subjects with normal 2-kHz hearing. Furthermore, filter widths for young subjects with 20- and 40-dB simulated hearing losses overlapped with those obtained from elderly subjects with corresponding degrees of actual hearing loss. One measure that did show significant differences between actual and simulated hearing losses was the degree of filter asymmetry; auditory filters in hearing-impaired listeners were more asymmetrical than those obtained from noise-masked normal-hearing subjects. The dynamic range of auditory filters, however, was comparable for hearing-impaired and noise-masked listeners. Lastly, post-filter detection efficiency was also similar for young and elderly subjects with equivalent hearing levels. These findings suggest that the reduced frequency selectivity often reported for older listeners can be attributed, primarily, to hearing loss rather than increased age. Implications of the results for speech perception in the elderly and models of hearing impairment are discussed.
为了区分年龄和听力损伤对频率选择性变化的影响，在四组受试者中测量了2千赫处的听觉滤波器形状：（1）听力正常的年轻受试者；（2）听力正常的老年受试者；（3）老年听力受损听众；以及（4）具有模拟听力损失的年轻听力正常听众。滤波器形状是使用带凹口噪声程序的修改版本得出的[格拉斯伯格和摩尔，《听觉研究》47，103 - 138（1990）]。在2千赫听力正常的年轻和老年受试者中，听觉滤波器的等效矩形带宽（ERB）没有显著差异。此外，具有20分贝和40分贝模拟听力损失的年轻受试者的滤波器宽度与相应实际听力损失程度的老年受试者的滤波器宽度重叠。一个确实显示实际听力损失和模拟听力损失之间存在显著差异的指标是滤波器不对称程度；听力受损听众的听觉滤波器比噪声掩蔽的听力正常受试者的听觉滤波器更不对称。然而，听力受损听众和噪声掩蔽听众的听觉滤波器动态范围相当。最后，听力水平相当的年轻和老年受试者的滤波器后检测效率也相似。这些发现表明，通常报道的老年听众频率选择性降低主要可归因于听力损失而非年龄增长。讨论了这些结果对老年人言语感知和听力损伤模型的意义。
