Binaural Speech Understanding With Bilateral Cochlear Implants in Reverberation Purpose The purpose of this study was to investigate whether bilateral cochlear implant (CI) listeners who are fitted with clinical processors are able to benefit from binaural advantages under reverberant conditions. Another aim of this contribution was to determine whether the magnitude of each binaural advantage observed inside a highly ... Research Article
Research Article  |   March 08, 2018
Binaural Speech Understanding With Bilateral Cochlear Implants in Reverberation
 
Author Affiliations & Notes
  • Kostas Kokkinakis
    Speech-Language-Hearing: Sciences & Disorders, University of Kansas, Lawrence
  • Disclosure: The author has declared that no competing interests existed at the time of publication.
    Disclosure: The author has declared that no competing interests existed at the time of publication. ×
  • Correspondence to Kostas Kokkinakis, who is now with the North American Research Laboratory, MED-EL GmbH, Innsbruck, Austria: kokkinak@ku.edu
  • Editor-in-Chief: Sumitrajit Dhar
    Editor-in-Chief: Sumitrajit Dhar×
  • Editor: Monita Chatterjee
    Editor: Monita Chatterjee×
Article Information
Hearing & Speech Perception / Acoustics / Hearing Disorders / Hearing Aids, Cochlear Implants & Assistive Technology / Research Articles
Research Article   |   March 08, 2018
Binaural Speech Understanding With Bilateral Cochlear Implants in Reverberation
American Journal of Audiology, March 2018, Vol. 27, 85-94. doi:10.1044/2017_AJA-17-0065
History: Received July 8, 2017 , Revised August 24, 2017 , Accepted September 20, 2017
 
American Journal of Audiology, March 2018, Vol. 27, 85-94. doi:10.1044/2017_AJA-17-0065
History: Received July 8, 2017; Revised August 24, 2017; Accepted September 20, 2017

Purpose The purpose of this study was to investigate whether bilateral cochlear implant (CI) listeners who are fitted with clinical processors are able to benefit from binaural advantages under reverberant conditions. Another aim of this contribution was to determine whether the magnitude of each binaural advantage observed inside a highly reverberant environment differs significantly from the magnitude measured in a near-anechoic environment.

Method Ten adults with postlingual deafness who are bilateral CI users fitted with either Nucleus 5 or Nucleus 6 clinical sound processors (Cochlear Corporation) participated in this study. Speech reception thresholds were measured in sound field and 2 different reverberation conditions (0.06 and 0.6 s) as a function of the listening condition (left, right, both) and the noise spatial location (left, front, right).

Results The presence of the binaural effects of head-shadow, squelch, summation, and spatial release from masking in the 2 different reverberation conditions tested was determined using nonparametric statistical analysis. In the bilateral population tested, when the ambient reverberation time was equal to 0.6 s, results indicated strong positive effects of head-shadow and a weaker spatial release from masking advantage, whereas binaural squelch and summation contributed no statistically significant benefit to bilateral performance under this acoustic condition. These findings are consistent with those of previous studies, which have demonstrated that head-shadow yields the most pronounced advantage in noise. The finding that spatial release from masking produced little to almost no benefit in bilateral listeners is consistent with the hypothesis that additive reverberation degrades spatial cues and negatively affects binaural performance.

Conclusions The magnitude of 4 different binaural advantages was measured on the same group of bilateral CI subjects fitted with clinical processors in 2 different reverberation conditions. The results of this work demonstrate the impeding properties of reverberation on binaural speech understanding. In addition, results indicate that CI recipients who struggle in everyday listening environments are also more likely to benefit less in highly reverberant environments from their bilateral processors.

Acknowledgments
The author gratefully acknowledges the individuals who participated in this study.
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