Approximately 22 million Americans have a hearing impairment. While hearing devices such as hearing aids (HAs) and cochlear implants (CIs) are successful in improving speech recognition for many hearing- impaired individuals, there is still significant variability in benefit, and speech recognition in noise remains a problem. One factor that may limit benefit, especially binaural benefit, is abnormal binaural spectral integration. A prerequisite for binaural integration is binaural fusion ? the fusion of stimuli from the two ears into a single auditory object. Our findings from the previous grant showed that unlike normal-hearing (NH) listeners, many HA and CI users experience abnormally ?broad? binaural fusion in the spectral domain, such that pitches that differ greatly in frequency between the two ears are still heard as a single percept. Individuals with broad fusion also experience abnormal binaural spectral integration - averaging and thus distortion of spectral information across the ears when disparate sounds are fused. We also showed broad fusion to be associated with binaural interference ? poorer speech recognition with two ears compared to one. More importantly, preliminary data show that broad fusion is associated with greater difficulty with understanding speech in challenging multi-talker listening situations, such as noisy restaurants. Difficulties with speech understanding in noise is a major complaint of both HA and CI users. In order to help hearing-impaired listeners reduce binaural interference and improve speech understanding in background noise, we need to understand the underlying causes and factors in broad fusion. The long-term goal of this research program is to investigate the effects, causes, and potential treatments for abnormal binaural spectral integration in hearing-impaired listeners. In this proposal we will: 1) determine how broad binaural fusion affects speech perception in quiet and in background talkers; and 2) investigate potential causes of broad binaural fusion in children and adults with HAs and CIs, focusing on peripheral spectral resolution, auditory experience, and top-down auditory processing factors. The proposed research will indicate the role of broad binaural spectral fusion in difficulties faced by hearing-impaired listeners, especially for speech understanding in background noise. Determination of the factors underlying broad fusion will inform future rehabilitation approaches to treat broad fusion, and help hearing-impaired listeners attain the same benefits of binaural hearing as NH listeners.

Public Health Relevance

The proposed research will increase our understanding of how hearing loss and hearing devices such as hearing aids and cochlear implants affect binaural processing of information. The results will guide future rehabilitation approaches using device programming or auditory training programs to reduce binaural interference effects and maximize the benefits of bilateral hearing devices for speech perception in quiet and in noise.

National Institute of Health (NIH)
National Institute on Deafness and Other Communication Disorders (NIDCD)
Research Project (R01)
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Auditory System Study Section (AUD)
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King, Kelly Anne
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Oregon Health and Science University
Schools of Medicine
United States
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Oh, Yonghee; Reiss, Lina A J (2018) Binaural Pitch Fusion: Effects of Amplitude Modulation. Trends Hear 22:2331216518788972
Reiss, Lina A J; Fowler, Jennifer R; Hartling, Curtis L et al. (2018) Binaural Pitch Fusion in Bilateral Cochlear Implant Users. Ear Hear 39:390-397
Reiss, Lina A J; Shayman, Corey S; Walker, Emily P et al. (2017) Binaural pitch fusion: Comparison of normal-hearing and hearing-impaired listeners. J Acoust Soc Am 141:1909
Oh, Yonghee; Reiss, Lina A J (2017) Binaural pitch fusion: Pitch averaging and dominance in hearing-impaired listeners with broad fusion. J Acoust Soc Am 142:780
Fowler, Jennifer R; Eggleston, Jessica L; Reavis, Kelly M et al. (2016) Effects of Removing Low-Frequency Electric Information on Speech Perception With Bimodal Hearing. J Speech Lang Hear Res 59:99-109
Reiss, Lina A J; Eggleston, Jessica L; Walker, Emily P et al. (2016) Two Ears Are Not Always Better than One: Mandatory Vowel Fusion Across Spectrally Mismatched Ears in Hearing-Impaired Listeners. J Assoc Res Otolaryngol 17:341-56
Reiss, Lina A J; Ito, Rindy A; Eggleston, Jessica L et al. (2014) Abnormal binaural spectral integration in cochlear implant users. J Assoc Res Otolaryngol 15:235-48