People with sensorineural hearing loss experience difficulties understanding speech in noisy environments, and may have difficulty separating a target voice from among many talkers, and localizing sounds in space. All of these deficits may be attributed to the functional effects of damage to cochlear structures, which include a loss of auditory sensitivity, alterations in loudness perception, and impairments of spectral and temporal processing in the auditory system. In this program of research, behavioral psychoacoustic methodologies and electrophysiological methods are used to study the deficits associated with frequency and time analysis in the impaired cochlea, and the impact of those deficits on the clear understanding of speech and the ability to enjoy music. For the next grant period, the focus of this research will be the study of temporal processing of complex sounds by people with hearing loss. Included are studies of complex pitch produced by harmonic and inharmonic complexes and aperiodic rippled noises, and studies of the ability to perceive the fine structure and envelopes in temporal waveforms. In addition, experiments will include measurement of evoked responses to stimuli with various temporal characteristics. The studies have as their goal the evaluation of the representation of temporal information in the higher auditory centers within the brain, when the inputs to those centers come from an impaired peripheral auditory system. It is hoped that an understanding of the manner in which the temporal information is distorted or lost, as determined by these studies, will help in understanding the functional deficits experienced by hearing-impaired people in their everyday lives.

Public Health Relevance

People who suffer from hearing loss often find that their ability to perceive pitch, to separate a target voice from other voices, and to localize sounds in space is impaired. The studies in this program of research investigate the underlying impaired functions of the inner ear that produce these deficits, with the goal of contributing to new hearing aid processing techniques or other rehabilitative treatments.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
Project #
Application #
Study Section
Auditory System Study Section (AUD)
Program Officer
Miller, Roger
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
Loma Linda Veterans Assn Research & Education
United States
Zip Code
Molis, Michelle R; Diedesch, Anna; Gallun, Frederick et al. (2013) Vowel identification by amplitude and phase contrast. J Assoc Res Otolaryngol 14:125-37
Bennett, Keri O'Connell; Billings, Curtis J; Molis, Michelle R et al. (2012) Neural encoding and perception of speech signals in informational masking. Ear Hear 33:231-8
Billings, Curtis J; Bennett, Keri O; Molis, Michelle R et al. (2011) Cortical encoding of signals in noise: effects of stimulus type and recording paradigm. Ear Hear 32:53-60
Molis, Michelle R; Leek, Marjorie R (2011) Vowel identification by listeners with hearing impairment in response to variation in formant frequencies. J Speech Lang Hear Res 54:1211-23
Lauer, Amanda M; Dooling, Robert J; Leek, Marjorie R (2009) Psychophysical evidence of damaged active processing mechanisms in Belgian Waterslager Canaries. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 195:193-202
Lauer, Amanda M; Molis, Michelle; Leek, Marjorie R (2009) Discrimination of time-reversed harmonic complexes by normal-hearing and hearing-impaired listeners. J Assoc Res Otolaryngol 10:609-19
Lauer, Amanda M; Dooling, Robert J; Leek, Marjorie R et al. (2007) Detection and discrimination of simple and complex sounds by hearing-impaired Belgian Waterslager canaries. J Acoust Soc Am 122:3615-27
Tufts, Jennifer B; Molis, Michelle R (2007) Perception of roughness by listeners with sensorineural hearing loss. J Acoust Soc Am 121:EL161-7
Lauer, Amanda M; Dooling, Robert J; Leek, Marjorie R et al. (2006) Phase effects in masking by harmonic complexes in birds. J Acoust Soc Am 119:1251-9
Tufts, Jennifer B; Molis, Michelle R; Leek, Marjorie R (2005) Perception of dissonance by people with normal hearing and sensorineural hearing loss. J Acoust Soc Am 118:955-67

Showing the most recent 10 out of 30 publications