Sandra Gordon-Salant, Ph.D. - US grants

This project aims to investigate specific speech perception problems of elderly listeners and without hearing impairment in ideal and noisy environments, and to determine whether stimulus modification techniques via digital editing effectively enhance the speech signal for these subjects. Rather than using lexical items that are typically analyzed for total percent correct, nonsense syllable stimuli will be presented to identify specific acoustic and phonetic features that are poorly perceived by the elderly. Further, discrete modifications of poorly perceived features will be employed, rather than previous techniques of transforming the entire signal. Testing of human subjects prior to and following each acoustic modification will be conducted to evaluate the effectiveness of each stimulus enhancement technique in a variety of listening environments.

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.

Project Summary/Abstract In response to an emerging need for scientists who can bring innovative skills and perspectives to problems in the hearing sciences, we continue to build upon our well established Training Program in Comparative and Evolutionary Biology of Hearing at the University of Maryland, College Park. The 17 Core Faculty in our group bring an extraordinarily broad range of expertise, from cellular and molecular biology to systems neuroscience, while also demonstrating a successful track record in training students. These capabilities allow us to offer a training program that not only emphasizes a comparative and evolutionary perspective to understanding the auditory system, but also does so across different levels of analysis. We propose new approaches to train the next generation of scientists to translate knowledge and methodologies across biomedical sciences, enabling breakthroughs that cannot be achieved through work confined to a single discipline and using a single model system. The next cycle of our training program promotes a focus on translational research, in which we will continue to expand our trainees' appreciation of the biomedical applications of basic research to solving problems concerned with hearing across the human life span, including prevention, diagnosis, and genetics of hearing impairment and relevant therapeutic interventions. Core Faculty are from four departments and one program at UMD (Biology, Psychology, Hearing and Speech Sciences, Electrical and Computer Engineering, and Neuroscience and Cognitive Science) and one program at the University of Maryland, Baltimore (UMB: Graduate Program in Life Sciences). Additional associated faculty from other UMD programs, NIDCD, and other regional institutions, such as UMB and Walter Reed National Military Medical Center, work closely with the Core Faculty and provide further research and training opportunities for pre- and post-doctoral trainees. The Training Program requests support for five predoctoral and two postdoctoral trainees. Predoctoral trainees are generally selected in middle to later training years, when they are primarily engaged in research. In addition to research training, all trainees take courses in the fundamentals of hearing and research ethics, attend seminars/courses in professional development and translational auditory science, as well as participate in all program activities. Emphasis throughout the program is to expose trainees to the breadth of work done in the program?s participating labs, and through this exposure, gain a better appreciation for the range of questions being asked and interdisciplinary research methods applied today in the hearing sciences.

ABSTRACT: ADMINISTRATIVE CORE (CORE A) Age-related hearing loss (ARHL) affects the majority of people over 65 years. Older people typically experience difficulty understanding speech in various degraded environmental conditions and the speech of atypical talkers, but hearing aids provide only limited benefit in these conditions. However, a renewed focus on auditory and cognitive training paradigms holds great promise for improving everyday communication by senior citizens. The overall objective of this Program Project Grant is to bring together 9 highly talented and productive investigators who use a range of methodologies and models to study the impact of auditory and cognitive training on neural plasticity in the central auditory nervous system. The Administrative Core provides leadership and administrative support for the entire program with three specific aims: 1) Provide scientific oversight and cohesion across the projects; 2) Facilitate collaboration among investigators across the three projects, including dissemination of joint publications; and 3) Manage resources in an equitable manner. Smooth, efficient administrative operation and engaged communication will enable investigators to devote their efforts to the scientific objectives of their respective projects and the common, cross-cutting ideas of the program project as a whole.

ABSTRACT: The detrimental effects of aging on auditory temporal processing have been well documented in humans and animal models. At present, there are gaps in knowledge of the extent to which these auditory tem- poral processing deficits can be mitigated in older adults with or without hearing loss through auditory training and neuroplasticity, to improve precision of neural timing and speech understanding. Our long-term goal is to determine the extent to which hearing deficits in older adults can be ameliorated with auditory training. We pro- pose an innovative approach to the investigation of aging, hearing, and neuroplasticity by marrying perceptual training experiments with electrophysiological measurements. The objectives are to compare young normal- hearing (YNH), older normal-hearing (ONH), and older hearing-impaired (OHI) adult listeners, and evaluate the improvements in perceptual and electrophysiological measures of temporal processing after explicit training on auditory temporal processing tasks. Our central hypothesis is that training of auditory temporal processing will produce concomitant improvements in both perceptual performance and neural encoding, which will close the gap in the age-related differences between groups. With strong preliminary data in hand, the central hypothesis will be tested by pursuing three specific aims: (1) Determine the extent to which perceptual training on temporal rate discrimination using simple non-speech stimuli improves perceptual and neural encoding in YNH, ONH, and OHI listeners; (2) Determine the extent to which perceptual training on speech cue discrimination in contrasting words differing in discrete temporal cues improves perceptual and neural encoding in YNH, ONH, and OHI lis- teners; and (3) Determine the extent to which perceptual training on the processing of sentences with increasing presentation rate can improve behavioral performance and neural encoding in YNH, ONH, and OHI listeners. The expected outcomes are that we will learn what perceptual training tasks lead to simultaneous improvements in perceptual and neural auditory temporal processing and the findings will produce a significant impact in older listeners who experience difficulty in communicating in daily life because they will lead directly to focused and novel forms of rehabilitation. This research is innovative because we will have established techniques that are proven to provide significant improvements in auditory temporal processing and speech perception, combined with evidence of improvements to neural encoding. These studies will serve the larger goals of the program project grant because they will help identify the neuroplastic mechanisms in the brain of humans that correspond to successful behavioral outcomes in younger and older adults

ABSTRACT: HUMAN SUBJECTS RESEARCH CORE (CORE C) Participation of human subjects is essential to Projects 2 and 3 of this Program Project grant, and involves extensive recruitment procedures, initial intake assessment of participants on numerous behavioral measures, and compliance with university, state, and federal regulations concerning the use of human subjects in research. This Core will function to streamline and unify these activities for multiple projects, with the overall objective of efficiently recruiting a large number of participants for Project 1 and Project 2 experiments who meet eligibility requirements. In addition, this Core will oversee the development and maintenance of a human subjects database, which will be HIPAA compliant and accessible to all investigators in the project. The four specific aims are: 1) Increase efficiency with which human subjects are recruited to the subprojects, including minority recruitment; 2) Ensure compliance with all issues surrounding the participation of human subjects in research; 3) Assist investigators in initial intake assessment of participants and maintain database of assessment measures on secure server; and 4) Assist investigators in scheduling participants for psychoacoustic, evoked potentials, and imaging studies. The Core is envisioned as a mechanism to support numerous human subjects activities on multiple projects, and thereby enable investigators to channel their time and effort into the scientific experiments that constitute this Program Project Grant. As a result, this Core will increase both productivity and the pace of research for the projects that involve humans as subjects.

ABSTRACT: OVERALL Significant hearing loss among older Americans exceeds 50%, suggesting that age-related hearing loss (ARHL) is one of the most common chronic health conditions experienced by older people. Untreated hearing loss is linked to depression, social isolation, and cognitive decline. While hearing aids remain the primary device for improving communication for those with ARHL, the take-up rate is relatively low at about 25%. Understanding speech in degraded listening situations (e.g., noise, reverberation, fast speech) continues to be a major challenge for older people, even among those with normal hearing. The underlying problem stems from limitations in the auditory periphery, the central auditory pathways, cognitive abilities, and alterations in the auditory-cognitive networks that support processing of auditory signals in noise and other forms of stimulus degradation. While a broad understanding of the problems experienced by older people is crystallizing, efforts to alleviate the problem through systematic investigation have been sparse. Thus, the over-arching goal of this Program Project Grant is to develop an integrative model of neuroplasticity in auditory aging, which will identify beneficial intervention strategies for mitigating the impact of auditory -cognitive decline with aging and will identify key loci of change in the auditory pathways that correlate with the most positive outcomes. The focus is on adaptive behavioral training to 1) enhance the auditory attention network to improve selective attention to relevant information and to suppress irrelevant information; 2) re-establish the appropriate balance between excitatory and inhibitory firing patterns to enhance auditory processing and cognition; and 3) improve neural timing to enhance precision of coding of acoustic stimuli to improve acoustic scene analysis and speech recognition. These targeted indices of positive neural plasticity will be monitored through a systems approach using behavior, electrophysiology, and imaging with humans and animals. The program includes 3 projects (P1: (Listening in noise, clutter, and reverberant environments ? central effects of aging and approaches to remediation; P2: Auditory temporal processing; P3: Speech Perception Training with High Cognitive Demand) and 3 cores (Core A: Administrative; Core B: Signal Processing and Data Analysis; Core C: Human Subjects Research Core), and involves 9 highly collaborative auditory and cognitive neuroscientists with a dedicated interest in solving the problems of speech communication with aging. If successful, the program has the potential to restore successful communication and improve quality of life for millions of older Americans.