Department of Communication Disorders, University of Massachusetts, Amherst, Massachusetts, USA.
Ear Hear. 2017 Nov/Dec;38(6):672-680. doi: 10.1097/AUD.0000000000000450.
It is well known from previous research that when listeners are told what they are about to hear before a degraded or partially masked auditory signal is presented, the speech signal "pops out" of the background and becomes considerably more intelligible. The goal of this research was to explore whether this priming effect is as strong in older adults as in younger adults.
Fifty-six adults-28 older and 28 younger-listened to "nonsense" sentences spoken by a female talker in the presence of a 2-talker speech masker (also female) or a fluctuating speech-like noise masker at 5 signal-to-noise ratios. Just before, or just after, the auditory signal was presented, a typed caption was displayed on a computer screen. The caption sentence was either identical to the auditory sentence or differed by one key word. The subjects' task was to decide whether the caption and auditory messages were the same or different. Discrimination performance was reported in d'. The strength of the pop-out perception was inferred from the improvement in performance that was expected from the caption-before order of presentation. A subset of 12 subjects from each group made confidence judgments as they gave their responses, and also completed several cognitive tests.
Data showed a clear order effect for both subject groups and both maskers, with better same-different discrimination performance for the caption-before condition than the caption-after condition. However, for the two-talker masker, the younger adults obtained a larger and more consistent benefit from the caption-before order than the older adults across signal-to-noise ratios. Especially at the poorer signal-to-noise ratios, older subjects showed little evidence that they experienced the pop-out effect that is presumed to make the discrimination task easier. On average, older subjects also appeared to approach the task differently, being more reluctant than younger subjects to report that the captions and auditory sentences were the same. Correlation analyses indicated a significant negative association between age and priming benefit in the two-talker masker and nonsignificant associations between priming benefit in this masker and either high-frequency hearing loss or performance on the cognitive tasks.
Previous studies have shown that older adults are at least as good, if not better, at exploiting context in speech recognition, as compared with younger adults. The current results are not in disagreement with those findings but suggest that, under some conditions, the automatic priming process that may contribute to benefits from context is not as strong in older as in younger adults.
先前的研究已经表明，当听众在听到一段有降质或部分掩蔽的听觉信号之前，就被告知他们即将听到什么时，语音信号就会“脱颖而出”，并且变得更加清晰可懂。本研究的目的是探讨这种启动效应在老年人中是否与年轻人一样强烈。
28 名老年人和 28 名年轻人共 56 名成年人聆听了一位女性说话者说出的“无意义”句子，这些句子是在两个说话者语音掩蔽（也是女性）或波动语音噪声掩蔽下呈现的，在 5 个信噪比下呈现。在听觉信号呈现之前或之后，计算机屏幕上会显示一个打字的标题。标题句与听觉句子要么完全相同，要么只有一个关键词不同。受试者的任务是判断标题和听觉信息是否相同或不同。辨别性能用 d'报告。从预期的标题呈现顺序中获得的表现提升推断出突出感知的强度。每组各有 12 名受试者完成了置信度判断，并完成了几项认知测试。
数据显示，两个受试组和两种掩蔽器都表现出明显的顺序效应，标题在前的条件下，相同-不同的辨别性能优于标题在后的条件。然而，对于两个说话者的掩蔽器，在整个信噪比范围内，年轻成年人从标题在前的顺序中获得的益处比老年人更大、更一致。尤其是在较差的信噪比下，老年人几乎没有表现出他们经历了突出效应的迹象，而突出效应被认为使辨别任务变得更容易。平均而言，与年轻受试者相比，老年受试者似乎更不愿意报告标题和听觉句子是相同的。相关分析表明，在两个说话者的掩蔽器中，年龄与启动益处呈显著负相关，而在该掩蔽器中，启动益处与高频听力损失或认知任务表现之间无显著关联。
先前的研究表明，与年轻人相比，老年人在利用言语识别中的语境方面至少同样出色，如果不是更好的话。当前的结果与这些发现并不矛盾，但表明在某些条件下，可能有助于语境受益的自动启动过程在老年人中不如在年轻人中强烈。
