Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016;21(3):127-31.
doi: 10.1159/000444740. Epub 2016 Apr 15.

Sound Source Localization by Normal-Hearing Listeners, Hearing-Impaired Listeners and Cochlear Implant Listeners

Michael F Dorman  1 , Louise H Loiselle, Sarah J Cook, William A Yost, René H Gifford
Affiliations

Sound Source Localization by Normal-Hearing Listeners, Hearing-Impaired Listeners and Cochlear Implant Listeners

Michael F Dorman et al. Audiol Neurootol. 2016.

Abstract

Objective: Our primary aim was to determine whether listeners in the following patient groups achieve localization accuracy within the 95th percentile of accuracy shown by younger or older normal-hearing (NH) listeners: (1) hearing impaired with bilateral hearing aids, (2) bimodal cochlear implant (CI), (3) bilateral CI, (4) hearing preservation CI, (5) single-sided deaf CI and (6) combined bilateral CI and bilateral hearing preservation.

Design: The listeners included 57 young NH listeners, 12 older NH listeners, 17 listeners fit with hearing aids, 8 bimodal CI listeners, 32 bilateral CI listeners, 8 hearing preservation CI listeners, 13 single-sided deaf CI listeners and 3 listeners with bilateral CIs and bilateral hearing preservation. Sound source localization was assessed in a sound-deadened room with 13 loudspeakers arrayed in a 180-degree arc.

Results: The root mean square (rms) error for the NH listeners was 6 degrees. The 95th percentile was 11 degrees. Nine of 16 listeners with bilateral hearing aids achieved scores within the 95th percentile of normal. Only 1 of 64 CI patients achieved a score within that range. Bimodal CI listeners scored at a level near chance, as did the listeners with a single CI or a single NH ear. Listeners with (1) bilateral CIs, (2) hearing preservation CIs, (3) single-sided deaf CIs and (4) both bilateral CIs and bilateral hearing preservation, all showed rms error scores within a similar range (mean scores between 20 and 30 degrees of error).

Conclusion: Modern CIs do not restore a normal level of sound source localization for CI listeners with access to sound information from two ears.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Sound source localization accuracy for normal hearing, hearing impaired and CI listeners. Each symbol indicates the performance of one listener. In the single ear condition, the half-filled symbols show the performance of SSD-CI patients when using their normal-hearing ear and the open circles show the performance of the same patients using their CI alone. The dotted line indicates the 95th percentile of scores for the normal hearing listeners.
See this image and copyright information in PMC

References

    1. Bichey B, Miyamoto R. Outcomes in bilateral cochlear implantation. Otolaryngology–Head and Neck Surgery. 2008;138:655–661. - PubMed
    1. Blauert J. Spatial Hearing. Cambridge: MIT Press; 1997.
    1. Dorman MF, Spahr A, Loiselle L, Zhang T, Cook S, Fiebig P, Yost W. Localization and speech understanding by a patient with bilateral cochlear implants and bilateral hearing preservation. Ear Hear. 2013;34(2):245–248. - PMC - PubMed
    1. Dorman MF, Loiselle L, Stohl J, Yost WA, Spahr A, Brown C, Cook S. Interaural level differences and sound source localization for bilateral cochlear implant patients. Ear Hear. 2014;35(6):633–640. - PMC - PubMed
    1. Dorman MF, Zeitler D, Cook S, Loiselle L, Yost WA, Wanna GB, Gifford RH. Interaural level difference cues (ILDs) determine sound source localization by single-sided deaf patients fit with a cochlear implant. Audiol Neurotol. 2015;20(3):183–188. - PMC - PubMed