MRC Institute of Hearing Research, Scottish Section, Glasgow Royal Infirmary, Glasgow G31 2ER, United Kingdom.
J Acoust Soc Am. 2012 Jul;132(1):369-79. doi: 10.1121/1.4728200.
Previous studies have shown a loss in the precision of horizontal localization responses of older hearing-impaired (HI) individuals, along with potentially poorer neural representations of sound-source location. These deficits could be the result or corollary of greater difficulties in discriminating spatial images, and the insensitivity to punctate sound sources. This hypothesis was tested in three headphone-presentation experiments varying interaural coherence (IC), the cue most associated with apparent auditory source width. First, thresholds for differences in IC were measured for a broad sampling of participants. Older HI participants were significantly worse at discriminating IC across reference values than younger normal-hearing participants. These results are consistent with senescent increases in temporal jitter. Performance decreased with age, a finding corroborated in a second discrimination experiment using a separate group of participants matched for hearing loss. This group also completed a third, visual experiment, with both a cross-mapping task where they drew the size of the sound they heard and the identification task where they chose the image that best corresponded to what they heard. The results from the visual tasks indicate that older HI individuals do not hear punctate images and are relatively insensitive to changes in width based on IC.
先前的研究表明，老年听力受损（HI）个体的水平定位反应精度下降，声源位置的神经表示可能也较差。这些缺陷可能是由于更难以区分空间图像，以及对点状声源不敏感的结果或必然结果。本研究通过三个耳机呈现实验检验了这一假设，实验中改变了耳间相干性（IC），这是与声源宽度的听觉感知最相关的线索。首先，为广泛的参与者样本测量了 IC 差异的阈值。与年轻的正常听力参与者相比，老年 HI 参与者在区分参考值的 IC 方面明显更差。这些结果与时间抖动的衰老增加一致。随着年龄的增长，表现下降，这一发现得到了第二个使用听力损失相匹配的另一组参与者进行的辨别实验的证实。该组还完成了第三个视觉实验，其中包括一个交叉映射任务，他们在其中绘制听到的声音的大小，以及一个识别任务，他们选择最能对应他们听到的声音的图像。视觉任务的结果表明，老年 HI 个体听不到点状图像，并且对基于 IC 的宽度变化相对不敏感。
