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Arnold School of Public Health


Public Health Relevance

Impact of hearing loss
Nearly one in three adults over the age of 65 have some degree of hearing loss significant enough to impact their daily life (Schoenborn & Marano, 1988) making hearing loss one of the leading public health concerns (NIDCD, 2010a).  However, less than 20% of these adults actually use hearing aids (NIDCD, 2010b) leading to significant social and economic ramifications (NIDCD, 2009).  One goal of Healthy People 2020 is to increase the use of assistive hearing technology (HHS, 2010).  However, after a house and a car, a hearing aid can be one of the largest out-of-pocket expenses for older adults, presenting a significant barrier to increased hearing aid use and making it essential to develop more affordable hearing technologies.

Importance of hearing technology
Audibility, or the ability to hear certain sounds, is the primary predictor of speech understanding abilities in older adults (Humes, 2007).  Hearing aid technology targets audibility by presenting sounds at greater levels so that people can hear.  Thus, using hearing aids to provide audibility is essential to maximizing speech understanding for older adults.

The problem
However, after audibility is restored, such as through hearing aid amplification, a number of other secondary factors can also impact speech understanding.  These factors appear to be related to either auditory processing abilities (e.g., temporal processing – how fast an individual’s auditory system can process rapid sounds) and/or cognitive processing abilities (e.g., memory, attention, executive control, speed of processing, word finding, use of context).  The involvement of these secondary sources becomes particularly pronounced in noisy and adverse listening environments, in part, because only partial speech information is preserved.  This partial speech signal places a larger burden on subsequent auditory and cognitive processing that is required to “sort out” the degraded signal.

Our research goal
The Speech Perception Laboratory is focused on identifying (1) the properties of speech that maximize speech understanding in adverse listening environments, (2) how the auditory and cognitive processing abilities of the listener impact how they are able to use these speech properties, and (3) how we may use these factors to predict, train, and enhance the speech understanding abilities of older adults. 

This information may then be applied to the development of cost-effective treatment strategies.  These may include training programs or software solutions that will help focus hearing technology to process the most informative speech cues that are best preserved in the noisy environment.  Importantly, this research will help to customize training and technology interventions to the individual’s auditory and cognitive processing abilities.

References
Health and Human Services (2010). Healthy People 2020. Retrieved April 18, 2011. (http://www.healthypeople.gov/hp2020).

Humes, L.E. (2007). The contributions of audibility and cognitive factors to the benefit provided by amplified speech to older adults. Journal of the American Academy of Audiology, 18, 590-603.

National Institute on Deafness and Other Communication Disorders (2009). NIDCD Working Group on Accessible and Affordable Hearing Health Care for Adults with Mild to Moderate Hearing Loss. Retrieved December 7, 2010
(http://www.nidcd.nih.gov/funding/programs/09HHC/summary.htm).

National Institute on Deafness and Other Communication Disorders (2010a). Quick Statistics, Retrieved December 7, 2010
(http://www.nidcd.nih.gov/health/statistics/quick.htm).

National Institute on Deafness and Other Communication Disorders (2010b). Use of Hearing Aids in 2001.  Retrieved December 7, 2010
(http://www.nidcd.nih.gov/health/statistics/Pages/long-hearingaids.aspx).

Schoenborn, C.A. & Marano, M. (1988). Current estimates from the National Health Interview Survey.Vital Health Stat,10, 1-233.