SPEECH UNDERSTANDING UNDER NONOPTIMAL CONDITIONS IN AGIN

拟议的研究集中在一个特别令人不安的听觉交流缺陷上，即老年人在非最佳听力条件下理解语言的能力经常显著下降，例如在有几个同时进行的谈话的社交环境中或在混响的房间里。这种缺陷，通常被称为衰老过程中“鸡尾酒会”效应的丧失，在过去25年里一直是越来越多研究的焦点；然而，目前对赤字的理解仍然不完整。我们之前的研究已经确定了这种缺陷的几个组成部分；那些与听力损失无关的人在音节和片段时间范围内都与空间加工和时间加工有关。拟议的研究将有两个具体目标：(1)调查老年人和年轻人中负责听觉信号时间分析的某些特定功能，并识别那些在受损时与非最佳听力条件下与年龄相关的言语理解缺陷相关的功能；(2)为期五年的研究；确定老年人在非最佳听力条件下言语理解能力下降的程度，可以通过一般听力学能力和/或特定听觉时间处理功能的恶化来预测。这个项目的意义在于，它将提供数据来解释为什么有些老年人能够理解受干扰的言语，而另一些人却不能。它还将阐明言语从干扰中分离的片段和超片段方面，并提供与年龄相关的言语理解能力下降及其与时间处理的联系的多维信息。在这样做的过程中，它很可能为下一代助听器的开发提供有用的数据，这些助听器能够帮助人们理解目前可用的放大助听器无法理解的语言。研究将由三个部分组成。第一部分将评估老年人群体中与年龄相关的听力学和听觉状态，包括语音处理和时间处理，并作为其他两部分的受试者选择阶段。第二部分将研究非语音信号在时间和频谱属性上的分离。第三部分将对一组老年人进行为期五年的跟踪研究，并监测在干扰下语音理解和时间处理功能下降的模式和速度。

The proposed research is focused on one particularly disturbing auditory communication deficit, namely, the often markedly reduced ability of elderly individuals to understand speech under non-optimal listening conditions, such as in social settings with several simultaneously ongoing conversations or in reverberating rooms. This deficit, often referred to as the loss of the "cocktail-party" effect in aging, has been the focus of an increasing number of investigations for the last 25 years; yet, present-day understanding of the deficit is still incomplete. Our previous research has identified several components of this deficit; those that were not connected to hearing loss were related to spatial processing as well as temporal processing both in the syllabic and segmental time ranges. The proposed study will have two specific objectives: (1) investigate, in elderly and young individuals, certain specific functions responsible for temporal analysis of auditory signals, and identify those that, when impaired, are correlated with age-related deficits of speech understanding under non-optimal listening conditions, and (2) over a five-year period, determine the extent to which a decline in speech understanding under non- optimal listening conditions in elderly individuals can be predicted from the deterioration of general audiological abilities and/or specific auditory temporal processing functions. Significance of the project lies in that it will provide data that may explain why some elderly individuals are able to understand speech in interference while others are not. It will also throw light on segmental and suprasegmental aspects of the segregation of speech from interference and supply information on the multidimensional profile of the age-related decline in speech understanding and its connection to temporal processing. In doing so, it is likely to supply data useful for the development of next-generation hearing aids able to help people understand speech where presently available amplifying hearing aids do not. The study will consist of three parts. Part I will assess the age-related audiological and auditory status, including speech processing and temporal processing, in a large group of elderly individuals, and serve as a subject selection stage for the other two parts. Part II will investigate segregation of nonspeech signals differing in well specified temporal and spectral attributes. Part III will follow groups of elderly subjects over a five-year period and monitor the pattern and the rate of decline of functions that enable speech understanding and temporal processing amidst interference.