Speech Recognition in Noise and Intonation Recognition in Primary-School-Aged Children, and Preliminary Results in Children with Cochlear Implants
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Fundamental frequency (F0), or voice pitch, is an important acoustic cue for speech intonation and is perceived most accurately through the fine spectral resolution of the normal human auditory system. However, relatively little is known about how young children process F0-based speech intonation cues. The fine spectral resolution required for F0 information has also been shown to be beneficial for listening in noise, a skill that normally-hearing children are required to use on a daily basis. While it is known that hearing-impaired adults with cochlear implants are at a disadvantage for intonation recognition and listening in noise following loss of fine spectral structure cues, relatively little is known about how young children with unilateral cochlear implants perform in these situations.
The goal of the current study was to quantify how a group of twenty normally-hearing children (6-8 years of age) perform in a listening-in-noise task and in a speech intonation recognition task. These skills were also measured in a small group of 5 children of similar age with unilateral cochlear implants (all implanted prior to the age of five). The cochlear implant participants in this study presumably had reduced spectral information, and it was hypothesized that this would be manifested as performance differences between groups. In the listening-in-noise task, sentence recognition was measured in the presence of a single-talker masker at different signal-to-noise ratios. Results indicated that the participants with cochlear implants achieved significantly lower scores than the normally-hearing participants. In the intonation recognition task, listeners heard re-synthesized versions of a single bisyllabic word ("popcorn") with systematically varying F0 contours, and indicated whether the speaker was "asking" or "telling" (i.e., question-like or statement-like). Both groups of children were able to use the F0 cue to perform the task, and no significant differences between the groups were observed. Although limited in scope, the results suggest that children who receive their cochlear implant before the age of five have significantly more difficulty understanding speech in noise than their normally-hearing peers. However, the two populations appear to be equally able to use F0 cues to determine speech intonation patterns.