Auditory temporal processing & speech understanding

我的研究表明，听觉系统的声音输入质量下降会降低工作记忆和口语理解方面的认知表现。即使在正确识别声音的情况下，也会观察到这种减少。声音的时序特性既包括声音精细结构的快速变化，也包括声音包络的缓慢变化。这些声音的变化为理解口语提供了明显的线索。我的实验表明，一些老年人在使用快节奏和慢节奏线索方面都有问题。本研究的第一个目标是研究使用非言语和言语刺激的这些不同类型的时间线索之间的相互关系。研究听力相对较好的老年人很有趣，因为他们使用声音时间线索的问题可能解释了为什么他们在嘈杂的环境中听力有困难。然而，当听力正常的年轻人在模拟老年人听觉时间处理问题的条件下表现时，也发现了类似的结果。因为当信号质量降低时，即使听者仍有可能准确识别单词，认知加工也会减少，因此研究计划的第二个目标是使用在线行为和生理测量（如测量大脑反应）来检查听觉/言语加工的时间过程，以便测量听力的时间过程。本研究的第三个目标是建立自下而上（耳朵对大脑）和自上而下（大脑对耳朵）的听力连接的时间限制模型，特别是在现实的、具有挑战性的听力条件下。例如，处理的速度随着信号的质量和上下文的支持度（例如，单词的句子上下文）而变化，但在某些限制下，理解失败，并且这种限制的性质是未知的。设计通信设备（如助听器）的工程师对这个话题非常感兴趣，心理学家、语言学家和其他希望了解人类在通信中如何使用感官信息的人也对这个话题感兴趣。

My research has shown that reductions in the quality of sound input to the auditory system can reduce cognitive performance on measures of working memory and spoken language comprehension. These reductions are observed even when sounds are correctly identified. The timing properties of sound include fast changes in the fine structure of sound, as well as slow changes in the sound envelope. These changes in sound provide distinct cues required for understanding spoken language. My experiments have demonstrated that some older adults have problems using both fast and slow timing cues. The first goal of the proposed research will be to examine the inter-relationships between these different types of timing cues using non-speech and speech stimuli. Older adults with relatively good hearing have been interesting to study because their problems using sound timing cues may explain why they have trouble listening in noisy situations. However, similar results have been found when younger adults with normal hearing perform in conditions that simulate the auditory temporal processing problems of older adults. Because cognitive processing is reduced when the quality of the signal is reduced, even when it is still possible for listeners to accurately recognize words, the second goal of the research plan is to examine the time course of auditory/speech processing using on-line behavioural and physiological measures such as the measurement of brain responses so that the time course of listening can be measured. The third goal of the proposed research will be to model the temporal limits on the connections between the bottom-up (ear to brain) and the top-down (brain to ear) aspects of listening, especially in realistic, challenging listening conditions. For example, the speed of processing varies with the quality of the signal and the supportiveness of the context (e.g., sentence context for a word), but at some limit comprehension fails and the nature of such limits is not known. This topic is of great interest to engineers designing communication devices (e.g., hearing aids), as well as being of interest to psychologists, linguists and others who wish to understand how humans use sensory information during communication.