Research/Clinical Interests
Hearing Loss and Aging
Speech Perception of Normal-hearing, hearing-impaired, and elderly listeners
Auditory Temporal Processing
Speech Enhancement Signal Processing Techniques
Courses Taught in the Past Five Years
HESP 311: Anatomy, Physiology, and Pathology of the Auditory System
HESP 606: Basic Hearing Measurement
HESP 636: Geriatric Audiology
HESP 701: Hearing Aids II
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Research/Clinical activities
- Principal Investigator on MERIT Award from the National Institute on Aging, entitled, Auditory temporal processes, speech perception and aging (2002 - 2012).
- Research supplement to promote diversity in health-related research, awarded to Dr. Sandra Gordon-Salant, title: Auditory temporal processes, speech perception and aging, (to support research training for Sarah A. Friedman).
- Ad Hoc Member, NIH Study Section (2003).
- Member, National Research Council Committee on Disability Determination for Individuals with Hearing Impairments
- Member, National Institute of Medicine Committee on Medical Evaluation of Veterans for Disability Compensation
Elderly people experience difficulty understanding speech in poor acoustic environments, even when they are compared to younger listeners with matched hearing sensitivity. The implication is that there are factors specifically associated with the aging process that contribute to the speech perception problems of elderly people. Research in this laboratory has focused on examining some of these factors using several approaches: (1) identifying the effects of age-related cognitive changes on speech perception performance; (2) identifying procedural variables that are sensitive to age effects on listening tasks; and (3) investigating the relationship of age-related auditory temporal processing deficits to deficits in speech recognition performance.
Age-related cognitive changes appear to affect speech understanding performance. For example, selected tasks that increase cognitive demand are sensitive to age effects. In addition, elderly listeners employ a more risky response criterion than younger listeners on speech recognition measures. Thus, elderly listeners may not understand a message but respond as if they did understand it, which leads to communicative dysfunction.
Elderly listeners exhibit abnormally poor performance on duration discrimination tasks, which is highly related to deficits on recognition of reverberant speech. This finding supports the hypothesis that aging is accompanied by changes in processing the temporal characteristics of acoustic stimuli, and that these temporal processing problems contribute to the speech perception problems of elderly listeners in degraded acoustic environments. Our studies have also shown that older people have particularly difficulty on speech recognition tasks and temporal processing tasks that increase stimulus and task complexity. Recent work also suggests that for speeded speech, the primary problem for older listeners is recognizing brief, impoverished acoustic cues in consonants, rather than the limited processing time to identify an entire sentence. Current studies are investigating methods to selectively slow down the spoken message to determine if this type of signal processing technique is beneficial for older listeners in understanding speech.
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