The long-term objective of this research program is to understand how the auditory system processes information in rooms with echoes. The experiments will focus on the precedence effect which describes aspects of competition for perception and localization between a sound source and its echoes. Proposed studies will systematically explore several perceptual phenomena that are involved in precedence and results will be interpreted in the context of a descriptive model of precedence. These studies will be conducted in parallel with the P.I.'s work on neural correlates of precedence in the auditory brainstem.
Aim 1 investigates the importance of the relative locations in a room of the source (lead) and echo (lag). This is a significant question since precedence is generally assumed to play an important role in directional hearing, however, little empirical data are available to support this assumption.
Aim 2 is to validate the use of virtual-acoustic-space (VAS) stimuli for precedence studies so that all directional cues can be brought under tight experimental control, allowing manipulation of the relative directional information provided to the two ears.
Aim 3 is to measure precedence in free field and using VAS stimuli in the azimuthal plane (where binaural disparity cues dominate localization) and in the median-sagittal plane (where spectral cues dominate localization). These studies test fundamental hypotheses concerning the extent to which monaural and binaural mechanisms mediate precedence.
Aim 4 extends investigations of precedence to a multiple-echo paradigm, thus bringing these studies closer to a realistic environment which normally contains a complex array of echoes. To date, very little research on this topic has been done. This work may help clarify why listeners with hearing impairments have difficulty extracting important information in the presence of reverberations and competing sounds, and may help develop hearing aids geared towards eliminating interference in reverberant environments.

Agency
National Institute of Health (NIH)
Institute
National Institute on Deafness and Other Communication Disorders (NIDCD)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29DC003083-02
Application #
2909904
Study Section
Hearing Research Study Section (HAR)
Program Officer
Donahue, Amy
Project Start
1998-05-01
Project End
2003-04-30
Budget Start
1999-05-01
Budget End
2000-04-30
Support Year
2
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Boston University
Department
Type
Schools of Engineering
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Winn, Matthew B; Litovsky, Ruth Y (2015) Using speech sounds to test functional spectral resolution in listeners with cochlear implants. J Acoust Soc Am 137:1430-42
Goupell, Matthew J; Yu, Gongqiang; Litovsky, Ruth Y (2012) The effect of an additional reflection in a precedence effect experiment. J Acoust Soc Am 131:2958-67
Lu, Thomas; Litovsky, Ruth; Zeng, Fan-Gang (2010) Binaural masking level differences in actual and simulated bilateral cochlear implant listeners. J Acoust Soc Am 127:1479-90
Garadat, Soha N; Litovsky, Ruth Y; Yu, Gongqiang et al. (2010) Effects of simulated spectral holes on speech intelligibility and spatial release from masking under binaural and monaural listening. J Acoust Soc Am 127:977-89
Garadat, Soha N; Litovsky, Ruth Y; Yu, Gongqiang et al. (2009) Role of binaural hearing in speech intelligibility and spatial release from masking using vocoded speech. J Acoust Soc Am 126:2522-35
Hawley, Monica L; Litovsky, Ruth Y; Culling, John F (2004) The benefit of binaural hearing in a cocktail party: effect of location and type of interferer. J Acoust Soc Am 115:833-43
Culling, John F; Hawley, Monica L; Litovsky, Ruth Y (2004) The role of head-induced interaural time and level differences in the speech reception threshold for multiple interfering sound sources. J Acoust Soc Am 116:1057-65
Litovsky, R Y; Shinn-Cunningham, B G (2001) Investigation of the relationship among three common measures of precedence: fusion, localization dominance, and discrimination suppression. J Acoust Soc Am 109:346-58
Litovsky, R Y; Hawley, M L; Fligor, B J et al. (2000) Failure to unlearn the precedence effect. J Acoust Soc Am 108:2345-52