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Single- and Multi-Channel Modulation Detection in Cochlear Implant Users

Single-channel modulation detection thresholds (MDTs) have been shown to predict cochlear implant (CI) users’ speech performance. However, little is known about multi-channel modulation sensitivity. Two factors likely contribute to multichannel modulation sensitivity: multichannel loudness summation...

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Detalles Bibliográficos
Autores principales: Galvin, John J., Oba, Sandy, Fu, Qian-Jie, Başkent, Deniz
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053447/
https://www.ncbi.nlm.nih.gov/pubmed/24918605
http://dx.doi.org/10.1371/journal.pone.0099338
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author Galvin, John J.
Oba, Sandy
Fu, Qian-Jie
Başkent, Deniz
author_facet Galvin, John J.
Oba, Sandy
Fu, Qian-Jie
Başkent, Deniz
author_sort Galvin, John J.
collection PubMed
description Single-channel modulation detection thresholds (MDTs) have been shown to predict cochlear implant (CI) users’ speech performance. However, little is known about multi-channel modulation sensitivity. Two factors likely contribute to multichannel modulation sensitivity: multichannel loudness summation and the across-site variance in single-channel MDTs. In this study, single- and multi-channel MDTs were measured in 9 CI users at relatively low and high presentation levels and modulation frequencies. Single-channel MDTs were measured at widely spaced electrode locations, and these same channels were used for the multichannel stimuli. Multichannel MDTs were measured twice, with and without adjustment for multichannel loudness summation (i.e., at the same loudness as for the single-channel MDTs or louder). Results showed that the effect of presentation level and modulation frequency were similar for single- and multi-channel MDTs. Multichannel MDTs were significantly poorer than single-channel MDTs when the current levels of the multichannel stimuli were reduced to match the loudness of the single-channel stimuli. This suggests that, at equal loudness, single-channel measures may over-estimate CI users’ multichannel modulation sensitivity. At equal loudness, there was no significant correlation between the amount of multichannel loudness summation and the deficit in multichannel MDTs, relative to the average single-channel MDT. With no loudness compensation, multichannel MDTs were significantly better than the best single-channel MDT. The across-site variance in single-channel MDTs varied substantially across subjects. However, the across-site variance was not correlated with the multichannel advantage over the best single channel. This suggests that CI listeners combined envelope information across channels instead of attending to the best channel.
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spelling pubmed-40534472014-06-18 Single- and Multi-Channel Modulation Detection in Cochlear Implant Users Galvin, John J. Oba, Sandy Fu, Qian-Jie Başkent, Deniz PLoS One Research Article Single-channel modulation detection thresholds (MDTs) have been shown to predict cochlear implant (CI) users’ speech performance. However, little is known about multi-channel modulation sensitivity. Two factors likely contribute to multichannel modulation sensitivity: multichannel loudness summation and the across-site variance in single-channel MDTs. In this study, single- and multi-channel MDTs were measured in 9 CI users at relatively low and high presentation levels and modulation frequencies. Single-channel MDTs were measured at widely spaced electrode locations, and these same channels were used for the multichannel stimuli. Multichannel MDTs were measured twice, with and without adjustment for multichannel loudness summation (i.e., at the same loudness as for the single-channel MDTs or louder). Results showed that the effect of presentation level and modulation frequency were similar for single- and multi-channel MDTs. Multichannel MDTs were significantly poorer than single-channel MDTs when the current levels of the multichannel stimuli were reduced to match the loudness of the single-channel stimuli. This suggests that, at equal loudness, single-channel measures may over-estimate CI users’ multichannel modulation sensitivity. At equal loudness, there was no significant correlation between the amount of multichannel loudness summation and the deficit in multichannel MDTs, relative to the average single-channel MDT. With no loudness compensation, multichannel MDTs were significantly better than the best single-channel MDT. The across-site variance in single-channel MDTs varied substantially across subjects. However, the across-site variance was not correlated with the multichannel advantage over the best single channel. This suggests that CI listeners combined envelope information across channels instead of attending to the best channel. Public Library of Science 2014-06-11 /pmc/articles/PMC4053447/ /pubmed/24918605 http://dx.doi.org/10.1371/journal.pone.0099338 Text en © 2014 Galvin III et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Galvin, John J.
Oba, Sandy
Fu, Qian-Jie
Başkent, Deniz
Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title_full Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title_fullStr Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title_full_unstemmed Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title_short Single- and Multi-Channel Modulation Detection in Cochlear Implant Users
title_sort single- and multi-channel modulation detection in cochlear implant users
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4053447/
https://www.ncbi.nlm.nih.gov/pubmed/24918605
http://dx.doi.org/10.1371/journal.pone.0099338
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