Auditory temporal processes, speech perception and aging

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DESCRIPTION (provided by applicant): This research program in speech perception and auditory psychophysics examines the hypothesis that many of the predominant difficulties in speech understanding of elderly listeners are related to underlying problems in auditory temporal processing. One form of degraded speech that is particularly difficult for elderly listeners to perceive is accented English. Alterations of speech stress and timing with accent may be viewed as a form of degradation in temporal aspects of speech prosody, and this type of temporal distortion is the focus of investigation in the next project period. Moreover, psychoacoustic results demonstrate that large age-related difficulties in temporal processing exist for the perception of auditory tempo and rhythmic characteristics of sequential stimulus patterns featuring a stressed tone. Listener processing difficulty could be attributed to periphera and/or central processing mechanisms, as well as various cognitive factors, including the degree of familiarity with prosodic features of different native languages. The project examines the relative contribution of peripheral hearing impairment, type of stimulus temporal complexity and cognitive demand, and the linguistic background experience of listeners on the processing of temporal prosody cues in speech and non-speech stimulus patterns. The project comprises four aims of investigation, each consisting of a series of speech and non-speech discrimination and recognition tasks. Aim 1 investigates the sources of age-related differences in temporal sensitivity for discrimination and identification of accented speech and correlated non-speech segments that vary in stress patterns. Aim 2 measures the influences of listener age and linguistic background on discrimination of temporal cues within speech and non-speech sequences that vary in prosodic temporal structure and presentation rate. Aim 3 examines the efficacy of auditory training paradigms with stimuli that feature temporal contrasts for improving perception of accented English and non-speech sequences by older people. Aim 4 will examine the effects of age on the ability to integrate temporal information across auditory and visual modalities in processing unaccented and accented speech and non-speech stimulus sequences. Participants in the project will include groups of subjects that differ by age, hearing sensitivity, and for some experiments, native language background. The research described in this application seeks to address one goal outlined by the National Institute on Aging: to develop effective interventions to maintain health and function and prevent or reduce the burden of age-related diseases, disorders, and disabilities. The approach in this research program involves (a) an assessment of the problems encountered in daily activities by the elderly population, (b) an analysis of specific task demands in relation to individual capabilities, and (c) basic research on sensory and perceptual changes with age and on the ameliorating effects of emerging technologies (including rehabilitation). This three-dimensional approach is expected to further progress toward improving communication and health-related quality of life for senior citizens.