Can spectral centroid explain voice pitch and vocal-tract length perception in normal-hearing and cochlear implant listeners?

PurposeThe focus of this study was to examine the influence of fundamental frequency (F0) and vocal tract length (VTL) modifications on speaker gender recognition in cochlear implant (CI) recipients for different stimulus types.MethodSingle words and sentences were manipulated using isolated or combined F0 and VTL cues. Using an 11-point rating scale, CI recipients and listeners with normal hearing rated the maleness/femaleness of the corresponding voice.ResultsSpeaker gender ratings for combined F0 and VTL modifications were similar across all stimulus types in both CI recipients and listeners with normal hearing, although the CI recipients showed a somewhat larger ambiguity. In contrast to listeners with normal hearing, F0-VTL and F0-only modifications revealed similar ratings in the CI recipients when using words as stimuli. However, when sentences were used, a difference was found between F0-VTL–based and F0-based ratings. Modifying VTL cues alone did not affect ratings in the CI group.ConclusionsWhereas speaker gender ratings by listeners with normal hearing relied on combined VTL and F0 cues, CI recipients made only limited use of VTL cues, which might be one reason behind problems with identifying the speaker on the basis of voice. However, use of the voice cues depended on stimulus type, with the greater information in sentences allowing a more detailed analysis than single words in both listener groups.

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Masking Effects in the Perception of Multiple Simultaneous Talkers in Normal-Hearing and Cochlear Implant Listeners

Trends in Hearing ◽

10.1177/2331216520916106 ◽

2020 ◽

Vol 24 ◽

pp. 233121652091610 ◽

Cited By ~ 2

Author(s):

Biao Chen ◽

Ying Shi ◽

Lifang Zhang ◽

Zhiming Sun ◽

Yongxin Li ◽

...

Keyword(s):

Cochlear Implant ◽

Normal Hearing ◽

Speech Signals ◽

Lexical Tone ◽

Voice Pitch ◽

Masking Release ◽

Tone Recognition ◽

The Mean ◽

Lexical Tone Recognition ◽

Extract Information

For normal-hearing (NH) listeners, monaural factors, such as voice pitch cues, may play an important role in the segregation of speech signals in multitalker environments. However, cochlear implant (CI) users experience difficulties in segregating speech signals in multitalker environments in part due to the coarse spectral resolution. The present study examined how the vocal characteristics of the target and masking talkers influence listeners’ ability to extract information from a target phrase in a multitalker environment. Speech recognition thresholds (SRTs) were measured with one, two, or four masker talkers for different combinations of target-masker vocal characteristics in 10 adult Mandarin-speaking NH listeners and 12 adult Mandarin-speaking CI users. The results showed that CI users performed significantly poorer than NH listeners in the presence of competing talkers. As the number of masker talkers increased, the mean SRTs significantly worsened from –22.0 dB to –5.2 dB for NH listeners but significantly improved from 5.9 dB to 2.8 dB for CI users. The results suggest that the flattened peaks and valleys with increased numbers of competing talkers may reduce NH listeners’ ability to use dips in the spectral and temporal envelopes that allow for “glimpses” of the target speech. However, the flattened temporal envelope of the resultant masker signals may be less disruptive to the amplitude contour of the target speech, which is important for Mandarin-speaking CI users’ lexical tone recognition. The amount of masking release was further estimated by comparing SRTs between the same-sex maskers and the different-sex maskers. There was a large amount of masking release in NH adults (12 dB) and a small but significant amount of masking release in CI adults (2 dB). These results suggest that adult CI users may significantly benefit from voice pitch differences between target and masker speech.

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