Effect of Dual-Carrier Processing on the Intelligibility of Concurrent Vocoded Sentences

Overview

Journal J Speech Lang Hear Res

Date 2018 Nov 21

PMID 30458525

Citations 1

Authors

Frederic Apoux

Brittney L Carter

Eric W Healy

Affiliations

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Abstract

Purpose: The goal of this study was to examine the role of carrier cues in sound source segregation and the possibility to enhance the intelligibility of 2 sentences presented simultaneously. Dual-carrier (DC) processing (Apoux, Youngdahl, Yoho, & Healy, 2015) was used to introduce synthetic carrier cues in vocoded speech.

Method: Listeners with normal hearing heard sentences processed either with a DC or with a traditional single-carrier (SC) vocoder. One group was asked to repeat both sentences in a sentence pair (Experiment 1). The other group was asked to repeat only 1 sentence of the pair and was provided additional segregation cues involving onset asynchrony (Experiment 2).

Results: Both experiments showed that not only is the "target" sentence more intelligible in DC compared with SC, but the "background" sentence intelligibility is equally enhanced. The participants did not benefit from the additional segregation cues.

Conclusions: The data showed a clear benefit of using a distinct carrier to convey each sentence (i.e., DC processing). Accordingly, the poor speech intelligibility in noise typically observed with SC-vocoded speech may be partly attributed to the envelope of independent sound sources sharing the same carrier. Moreover, this work suggests that noise reduction may not be the only viable option to improve speech intelligibility in noise for users of cochlear implants. Alternative approaches aimed at enhancing sound source segregation such as DC processing may help to improve speech intelligibility while preserving and enhancing the background.

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PMID: 38816900 PMC: 11493516. DOI: 10.1097/AUD.0000000000001532.

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