The long-term objective of our research is to understand the wide variation in speech perception of individuals with hearing loss who are candidates for hearing aids or cochlear implants, an important challenge that confronts clinicians. We know that speech perception is reflected in auditory pathway physiology. In the auditory cortex, timing, intensity and frequency cues are represented by cortical neural activity and ultimately linked to perceptual performance. Although we can assess the perception of sounds, much less is known about the underlying neurophysiology of the central auditory system. Specifically, the experiments in this study are designed to test the hypotheses that there are differences in the tonotopic organization and the asymmetric activation patterns of the central auditory system in good and poor perceivers of speech. To accomplish our research, we will use a multidisciplinary approach that combines outcome, neurophysiology and functional magnetic resonance imaging (fMRI) in normal listeners and individuals with hearing loss. Measures such as evoked potentials, which are inherently dependent upon neural synchrony, allow us to evaluate the critical components of neural encoding. Neuroimaging techniques such as fMRI, can produce distinct localized images corresponding to auditory cortex activation. Finally, using fMRI, we will investigate whether tonotopic organizational patterns can be identified and relate to speech perception for cochlear implant recipients with a magnetless cochlear implant system. Overall, this research will not only result in a better understanding of the physiology of the auditory cortex, but also a better understanding of the functional significance of tonotopic organization and hemispheric differences in both normal hearing listeners and those with hearing loss.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
Mentored Patient-Oriented Research Career Development Award (K23)
Project #
7K23DC005410-05
Application #
7120717
Study Section
Communication Disorders Review Committee (CDRC)
Program Officer
Sklare, Dan
Project Start
2002-04-22
Project End
2007-03-31
Budget Start
2005-09-01
Budget End
2006-03-31
Support Year
5
Fiscal Year
2005
Total Cost
$81,013
Indirect Cost
Name
Washington University
Department
Otolaryngology
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
King, Sarah E; Firszt, Jill B; Reeder, Ruth M et al. (2012) Evaluation of TIMIT sentence list equivalency with adult cochlear implant recipients. J Am Acad Audiol 23:313-31
Firszt, Jill B; Holden, Laura K; Reeder, Ruth M et al. (2009) Speech recognition in cochlear implant recipients: comparison of standard HiRes and HiRes 120 sound processing. Otol Neurotol 30:146-52
Alkaf, Farah Mohd; Firszt, Jill B (2007) Speech recognition in quiet and noise in borderline cochlear implant candidates. J Am Acad Audiol 18:872-82
Firszt, Jill B; Koch, Dawn Burton; Downing, Mark et al. (2007) Current steering creates additional pitch percepts in adult cochlear implant recipients. Otol Neurotol 28:629-36
Wackym, P Ashley; Runge-Samuelson, Christina L; Firszt, Jill B et al. (2007) More challenging speech-perception tasks demonstrate binaural benefit in bilateral cochlear implant users. Ear Hear 28:80S-85S
Firszt, Jill B; Ulmer, John L; Gaggl, Wolfgang (2006) Differential representation of speech sounds in the human cerebral hemispheres. Anat Rec A Discov Mol Cell Evol Biol 288:345-57
Firszt, Jill B; Wackym, Phillip A; Gaggl, Wolfgang et al. (2003) Electrically evoked auditory brain stem responses for lateral and medial placement of the Clarion HiFocus electrode. Ear Hear 24:184-90
Lasota, Katie J; Ulmer, John L; Firszt, Jill B et al. (2003) Intensity-dependent activation of the primary auditory cortex in functional magnetic resonance imaging. J Comput Assist Tomogr 27:213-8