Larry Humes - US grants

[unreadable] DESCRIPTION (provided by applicant): Those over the age of 65 years represent the most rapidly growing group within the U.S. population. Approximately 25% of these individuals have significant hearing loss that interferes with everyday communication. Nonetheless, of those elderly who could benefit from the use of hearing aids, only about 20% actually seek them out and, of those who do purchase hearing aids, many are dissatisfied with them or discontinue using them. This project seeks to identify factors that underlie the successful use of hearing aids and to develop ways to improve the benefit received from hearing aids by the elderly. There are two primary components to the proposed project: (1) an examination of laboratory-based measures of cognitive function, especially attention, and their association with the speech-understanding performance of elderly hearing-aid wearers while they are wearing their hearing aids; and (2) a clinical investigation of the factors underlying individual differences in subjective benefit, satisfaction, and hearing aid usage among elderly hearing-aid wearers. For the laboratory studies, a series of experiments is proposed in each of three areas: (1) age- and hearing-loss-related differences in selective attention to different cues in multidimensional, speech-like sounds; (2) the role of cognitive factors, either lexical memory or selective attention, in the improvement of aided speech-recognition performance with training; and (3) the interaction of selective and divided attention with another key cognitive ability, working-memory capacity, and the contributions of these cognitive factors to the recognition of speech while other speech is in the background. The clinical study, on the other hand, seeks to determine how many dimensions of hearing-aid outcome are represented by measures of hearing-aid satisfaction, usage, and subjective benefit. Specifically, do these measures represent one, two or three separate aspects of hearing-aid outcome? In addition, variables underlying individual differences in each measure of outcome will be identified so that performance along each dimension can be both better understood and enhanced. [unreadable] [unreadable]

Many of the elderly are hearing impaired with the hearing impairment sufficient to have an adverse effect on their ability to understand speech. The proposed project examines various factors which may contribute to the speech-understanding difficulties experienced by the hearing-impaired elderly. The proposed project uses a cross-sectional approach to examine age-related differences in two primary aspects of the speech-understanding process: (1) peripheral encoding mechanisms; and (2) cognitive processing. In the area of peripheral encoding mechanisms, experiments will investigate haw much of the speech-understanding deficits of the hearing-impaired elderly can be explained by the loss of hearing sensitivity alone and the extent to which the encoded representation of the acoustic stimulus is degraded internally by the sensorineural hearing loss. Modeling of the internal degradation that accompanies sensorineural hearing loss for simple and complex acoustic stimuli, including speech signals, will also be performed. Age-related differences in the cognitive processing of speech will also be examined. It is generally hypothesized that degradation of the speech stimuli, whether degraded internally (processed through an ear with sensorineural hearing loss) or externally (noise, reverberation, synthetic speech), will place increased demands on higher-level cognitive processing of speech stimuli. It is further hypothesized that elderly hearing- impaired listeners have a general deficit in the speed of cognitive processing that interacts with the increased processing demands associated with the degraded peripheral input to produce severe speech-understanding difficulties in this population. The interaction of deficits in cognitive processing with degradation in peripheral input will be investigated through examination of age-related differences in primary and secondary memory and in the use of contextual information for internally and externally degraded speech.

DESCRIPTION (provided by applicant): In the 2000 U.S. Census, 35 million Americans over 65 years of age were counted, representing 12.4% of the U.S. population. Approximately 30% of those over age 65 in the U.S. have a significant hearing loss that is sufficient to make them hearing-aid candidates. Yet, only about 20% of those who could benefit from hearing aids actually seek them out and, of those who do seek them out, only about 40-60% are satisfied with them and use their hearing aids regularly. Nonetheless, those over 60 years of age still represent the largest group of hearing-aid purchasers in the U.S., with those over age 60 purchasing about 2/3 of the hearing aids sold. Thus, understanding the factors that determine hearing-aid benefit and developing means to improve benefit are significant issues for many older adults in the U.S. The most common communication complaint of older adults with impaired hearing is that they can hear speech, but can't understand it. This is especially true when there are competing sounds, typically other speech, in the background. Hearing aids, to be effective, must address this common complaint and improve speech understanding, especially in backgrounds of competing speech. Hearing aids have the potential to improve speech communication by restoring the audibility of previously inaudible speech sounds, typically high-frequency speech sounds for older adults, but this potential does not appear to be realized. In the proposed project, we intend to examine further the aided speech-understanding performance of older adults in backgrounds of competing speech. The contributions of central and cognitive factors to the performance of older adults in these situations represent the focus of a series of laboratory experiments. Experiments address the ability of older listeners to use sound-segregation cues to selectively attend to the message from one talker while ignoring competing messages from other talkers. Additional experiments assess whether it is the fluctuating nature of the competing speech stimulus, the semantic/syntactic structure of the competing speech stimulus, or both, that underlie the difficulties experienced by older adults. Finally, another experiment examines the ability of older adults to reconstruct the speech message from the temporal, spectral, and spectro-temporal fragments heard in noise. The most common communication complaint of older adults with impaired hearing is that they can hear speech, but can't understand it, especially when there are competing sounds, typically other speech, in the background. Hearing aids, to be effective for older adults, must address this common complaint and improve speech understanding. In the proposed project, we intend to examine further the factors impacting the aided speech- understanding performance of older adults in backgrounds of competing speech.

Kidd
0079468

This proposal seeks funds to equip two laboratories to be used as shared resources for a wide range of experiments in speech and hearing sciences. The two facilities are: (1) the Multi-station Auditory-Visual Laboratory (MAV Lab) and (2) the Anechoic-Echoic Laboratory (AEL). Both laboratories are to be equipped with networked computers with flexible experiment-control software for stimulus presentation and data collection. The MAV Lab will also serve as a general purpose multi-station testing facility for evaluation of speech and language abilities and for speech recording. The requested equipment will allow a very productive group of researchers to conduct a wider range of research with much greater efficiency.

The Multi-station Auditory-Visual Laboratory (AM FLab) will be constructed to house up to ten study participants in two large double-walled, sound-treated booths that will permit computer presentation of auditory and visual stimuli at each of ten independent testing stations. The large sound-treated rooms will enable threshold-level sound intensities to be presented via headphones in various experiments while concurrently allowing for the testing of up to ten participants simultaneously. The use of two separate booths in this space will provide more flexibility in the use and scheduling of the facilities. Each testing station will be equipped with a 17" highresolution color monitor, keyboard and mouse, as well as a microphone for voice recording. These components from each testing station will be connected to separate Pentium III, 600-MHZ computers with accompanying electronic equipment needed for sophisticated listening experiments (programmable attenuators with >96 dB signal-to-noise ratios; multi-channel, 16bit, digital-to-analog converters with signal-processing array processors). The ten computers (one per testing station) will be housed in a separate room outside the double-walled booth to minimize internally generated noise in the test area. The MAV Lab will enable state-of-the-art testing in the areas of auditory perception, speech perception, visual perception, combined auditory-visual perception, language development, and general cognitive function.

The Anechoic-Echoic Laboratory (AEL) will be housed in a facility that was refurbished by Indiana University approximately seven years ago. It is a unique facility with a large anechoic chamber immediately adjacent to an equally large echoic room, both specially constructed to eliminate outside noise and vibration. The facility, however, has seen very little use because of the lack of appropriate test equipment. This proposal requests funds to equip both the anechoic and echoic chambers with a computer-based stimulus-delivery and response-collection system, a computer dedicated for use in making complex acoustical measurements. A computer-controlled loudspeaker system that will permit precise, quiet movement of a loudspeaker at specified velocities along a circular path surrounding the human listener will be installed in the anechoic chamber. This system will be used to study the localization of sound, the perception of speech in background noise under real-world conditions, and the perception of the movement of sound sources in space.

These two facilities will be used by several investigators in the Department of Speech and Hearing Sciences and their colleagues in other departments at Indiana University and at other universities. Several of the investigators will use the facilities for multidisciplinary projects that include a wide range of populations (e.g., infants, grade-school children, young adults, and the elderly) and many different disciplines (including physics, engineering, and architectural acoustics). These new laboratories will also provide state-of-the-art facilities for research training of students in Speech and Hearing Sciences. Additionally, the special capabilities of the AEL will be used for collaborative research with hearing aid manufacturers and engineers in the evaluation of new directional microphone technologies.

[unreadable] DESCRIPTION (provided by applicant): This application seeks funding for an international and interdisciplinary research conference on the problem of speech communication by older adults. Scientists approaching this problem have typically been either working in the area of sensory and perceptual processing, especially hearing, or in the area of cognitive science. Speech communication involves both sensory-perceptual processes and cognitive processes. Aging can have a negative impact on either or both of these systems. By bringing together scholars actively involved in research in both of these areas, it is hoped that further progress will be made in understanding and remedying the speech- communication difficulties of older adults. The first conference, held in October, 2005, was very successful and funding is being requested for two additional conferences to be held in October of 2007 and 2009. Approximately 30% of Americans over the age of 65 have significant speech- communication problems. The proposed conference should lead to further progress in understanding and remedying the speech-communication difficulties of older adults. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): It has been estimated that at least 10-15% of the elderly American population, or 2-3 million individuals, experience impairments in more than one sensory modality, including hearing, sight and touch. The proposed project assesses the performance of a large group of young and elderly adults on a battery of tests that measure temporal-processing abilities in the auditory, visual and tactual senses. The primary aims of the proposed project are: (1) to determine whether temporal processing of sensory input by adults is affected by advancing age in either the auditory, visual or tactile modalities; (2) to establish whether correlations exist across sensor modalities for similar measures of temporal processing obtained from the same set of young and elderl, participants; and (3) to determine whether various measures of temporal processing within a particular modality are correlated, regardless of age. The first aim is addressed primarily through examination of differences in performance on auditory, visual and tactile measures of temporal processing between groups comprised of the same set of young and elderly individuals, as well as through correlations with age. Based on isolated experiments on temporal processing conducted previously within each sensory modality, it is anticipated that elderly subjects, as a group, will perform worse than young adults on most of these tasks and will likely do sc for each modality. Since a parallel set of temporal measures will be obtained across all three modalities however, the proposed project also will be able to address the aims identified above through correlational analyses. In addition, regarding the second aim, within a given age group, correlations in performance across modalities on a particular temporal-processing measure will provide strong evidence that such processing is amodal, likely sharing a common underlying central or cognitive process. In this way, use of young and elderly subjects in the proposed project will not only shed light on the nature of sensory impairments experienced b the elderly, but also on the nature of temporal processing mechanisms across modalities regardless of age. Structural equation modeling will be used to examine the correlations between measures and address the degree to which different modalities share a common temporal processing mechanism that is affected by age.

DESCRIPTION (provided by applicant): In the 2000 U.S. Census, 35 million Americans over 65 years of age were counted, representing 12.4% of the U.S. population. Approximately one-third of those over age 65 in the U.S., or roughly 12 million Americans, have a significant hearing loss that is sufficient to make them hearing-aid candidates. Yet, only about 20% of those who could benefit from hearing aids actually seek them out and, of those who do seek them out, only about 40-60% are satisfied with them and use their hearing aids regularly. To be successful, hearing aids must address the most common communication complaint of older adults with impaired hearing: they can hear speech, but can't understand it. This is especially true when there are competing sounds, typically other speech, in the background. Although contemporary hearing aids provide significant benefits to older adults, to restore aided speech communication to normal or near-normal performance levels and optimize the chances for success, the speech-to-noise ratio needs to be enhanced considerably. For many older adults, contemporary hearing-aid technologies are unable to enhance the speech-to-noise ratio sufficiently. An alternate approach to this problem is to train the older adult to make better use of the information in the existing speech-to-noise ratio. The present proposal continues our work on such an auditory-training approach. Specifically, we have developed an innovative lexically motivated word-based auditory-training protocol which has been demonstrated repeatedly to be efficacious under controlled laboratory conditions. Our objective is to transition this protocol from an efficacious laboratory system to an effective in-home auditory-training system for older adults. The first step in this transition is an additional laboratory study of the optimal dosing and duration of the training regimen. Concurrently, the platform for the in-home system will be developed. Finally, a clinical trial of the in-home training system will be conducted using a three-branch parallel design with control, placebo-training, and experimental-training groups.

DESCRIPTION (provided by applicant): According to recent population estimates made by the U.S. Census Bureau, about 39 million Americans are over 65 years of age, representing 13% of the U.S. Approximately 35% of those over age 65 in the U.S., or about 13.6 million older Americans, have a significant hearing loss that is sufficient to make them hearing-aid candidates. Yet, only about 20% of those who could benefit from hearing aids actually seek them out. Limitations in the accessibility and affordability of hearing health care seem to be primary factors underlying the low percentage of older Americans who purchase hearing aids. The purchase price of the hearing aids and the typical service- delivery model represent key factors that appear to limit the accessibility and affordability of hearing aids. As the production costs of the devices themselves are fairly low, the justification for the higher purchase prices is often grounded in the professional services provided in the selection, programming, fitting and evaluation of the devices. This project proposes to conduct research that would provide new knowledge about the impact of purchase price and service-delivery model on hearing-aid outcomes. The proposed study will acquire this knowledge through a Phase-II double-blinded, placebo-controlled, randomized clinical trial with five parallel branches. In addition to a placebo branch, the remaining four branches represent factorial combinations of service-delivery model (current best practices and over-the-counter simulation) and purchase price (low and typical). Non-inferiority analyses will be performed to compare the outcomes of the current best-practices model to alternative combinations of service-delivery model and purchase price. Based on the results obtained, the findings could have considerable impact on the accessibility and affordability of hearing health care for older adults with mild-to-moderate hearing loss.