Sara K. Mamo, Ph.D. - US grants

DESCRIPTION (provided by applicant): The long-term aim of this project is to determine the relationship between temporal processing deficits apparent in the brainstem response to complex acoustic cues and speech perception difficulties in noisy backgrounds. The specific objective of the proposed research is to characterize the brainstem encoding of speech and other complex stimuli in young and older adults. The proposed experiments are designed to compare younger and older listeners with near-normal audiometric hearing in order to understand how reduced fidelity of temporal processing affects encoding of the temporal components of speech and, consequently, speech perception. Aim 1 will employ auditory brainstem response measures elicited by speech as an index of periodicity coding. This study will test the primary hypothesis that the degree of periodicity coding measured at the level of the brainstem is dependent on stimulus duration. Aim 2 will model temporal deficits exhibited in the aging auditory system by estimating a measure of 'internal noise' for the older adults. This study will rely on an evaluation of the brainstem response elicited by speech stimuli that has been corrupted using a temporal jitter model. Aim 3 will relate the electrophysiological measures to psychophysical and speech perception measures in young and older adults. Both the psychophysical task (detection of dichotic low-rate frequency modulation) and the speech task (modulation masking release) are designed to capture aspects of temporal processing. The training program involves strong mentorship in research design, especially in the domain of signal processing (stimulus generation, response analysis, etc.) and data analysis essential to the proposed research. Results will contribute to a more refined understanding of sub-cortical processing of speech sounds and the effects of temporal processing deficits on speech processing. The translational emphasis of this project is to optimize the use of complex-ABR measures for the assessment of clinical populations who experience difficulty perceiving speech despite audiometrically normal hearing. PUBLIC HEALTH RELEVANCE: Speech-evoked auditory brainstem responses have been used to investigate auditory processing in a variety of clinical populations. This project will advance our understanding of how these responses depend on the characteristics of the speech sound as well as on the integrity of temporal processing in the affected ear. Project results will have direct clinical relevance in terms of the use of speech-evoked auditory brainstem responses in the assessment of populations with speech perception difficulties.

Project Summary/Abstract The long-term objective of this proposal is to increase the accessibility and affordability of hearing loss treatment for older adults with hearing loss and mild cognitive impairment (MCI) or Alzheimer?s disease and related dementias (ADRD) by improving our knowledge base of speech perception abilities in this population and directly translating that knowledge into a tailored approach to hearing intervention. Age-related hearing loss (ARHL) in persons with MCI or dementia may exacerbate dementia-related symptoms such as depression, apathy, agitation/aggression. Moreover, engagement and activity participation are recognized as critical aspects of dementia care management, but those individuals who also experience ARHL are at a disadvantage. The aims of this proposal include basic science investigation as well as refinement and pilot testing of a behavioral communication intervention. Aim 1 will focus on controlled laboratory measures of speech perception abilities in complex background noise as well as the ability to benefit from common communication repair strategies in groups of older adults with MCI/early stage dementia and older adults matched with these individuals for age and hearing thresholds. This aim will improve our theoretical understanding of speech perception abilities for older adults with cognitive impairment. The investigations undertaken in Aim 2 will focus on assessing and defining the functional burden of ARHL and cognitive impairment in group care settings for older adults. A mixed methods approach will be undertaken in Aim 2 to better understand how the quantitative aspects of the prevalence of ARHL and cognitive impairment interact with the acoustic environment as well as the behavioral/social context of staff and peer interactions in the group care setting. Finally, the multicomponent hearing care intervention to be tested in Aim 3 includes acoustic modifications, staff training, and non-custom personal amplification use with target individuals in a group care setting. This feasibility study will lead to the refinement of the intervention protocols to be used in a future grant application that will test the real-world efficacy of the intervention in a cluster- randomized control trial. Dr. Sara Mamo is a tenure-track Assistant Professor in the Department of Communication Disorders in the School of Public Health and Health Sciences at the University of Massachusetts Amherst. With this Mentored Patient-Oriented Research Career Development Award, Dr. Mamo intends to develop methodological skills related to testing speech perception and improve her knowledge base in the theoretical underpinnings of behavioral interventions, the evidence-based approaches to clinical management of dementia, and statistical analyses of longitudinal outcomes. These key training components will support the development of a hearing care intervention that can be integrated into comprehensive care of older adults with cognitive impairment, and measure the long-term downstream effects associated with the intervention in future randomized trials.