BME PhD Prospectus Defense - Hari Bharadwaj

1:00 pm on Friday, June 21, 2013
3:00 pm on Friday, June 21, 2013
44 Cummington St, Room 203
Title: "Individual Differences in Suprathreshold Encoding of Sound and Auditory attention"

Barbara Shinn-Cunningham (Chair Advisor), BME, BU
Steve Colburn, BME, BU
Jason Ritt, BME, BU
Adrian K.C. Lee, SPHSC, U.Washington, Seattle

The ability to attend to a sound source of interest while ignoring irrelevant sounds is vital to navigating through the complex acoustic scenes of everyday life. Yet, sensorineural hearing loss from noise exposure, aging, and other factors can interfere with the ability to direct auditory attention, degrading the quality of life for an estimated 1 in 5 Americans. Moreover, even among listeners with “clinically normal hearing”, there are considerable individual differences in the ability to selectively attend to one sound source and filter out competing sounds. Auditory attention is a complex neuropsychological process involving several stages of sound processing. Concomitantly, while some of the differences in individual ability arise due to deficits in peripheral and brainstem encoding of acoustic information, others are primarily due to differences in higher-order, cortical processing in attentional control. Characterizing both the bottom-up and top-down factors affecting an individual’s ability to direct auditory attention will not only enhance our understanding of the neural mechanisms facilitating auditory attention, but will also allow us to understand the mechanisms causing different sources of hearing impairment that haven’t previously been identified and classified under the umbrella term of "central auditory processing disorders". Such insight will, in turn, enable development of new clinical and therapeutic tools to address hearing loss that previously had no effective treatment. Taking an interdisciplinary approach, the current project seeks to understand individual differences in perceptual ability by directly relating individual behavioral measures to non-invasive electrophysiological measures of both brainstem and cortical function; this will be effected through quantitative modeling of the auditory system that elucidates differences in how individual listeners encode and process sound.