Processing of Acoustic Information in Lexical Tone Production and Perception by Pediatric Cochlear Implant Recipients

Mandarin-speaking Children With Cochlear Implants Face Challenges in Using F0 Expansion to Express Contrastive Focus

OBJECTIVES

Children with cochlear implants (CIs) face challenges in perceiving fundamental frequency (F0) information because CIs do not transmit F0 effectively. In Mandarin, F0 can contrast meanings at the word level, that is, via lexical tones with distinct F0 contours, and signal contrastive relations between words at the utterance-level, that is, via contrastive focus with expanded F0 range and longer duration. Mandarin-speaking children with CIs have been reported to face challenges in producing distinct F0 contours across tones, but early implantation facilitates tonal acquisition. However, it is still unclear if utterance-level prosody, such as contrastive focus, is also challenging for these children, and if early implantation also offers benefits for focus production. Therefore, this study asked how accurately children with CIs can produce contrastive focus, and if early implantation leads to more accurate focus production, with acoustic patterns approaching that of children with typical hearing (TH).

DESIGN

Participants included 55 Mandarin-speaking children (3 to 7 years) with CIs and 55 age-matched children with TH. Children produced noun phrases with and without contrastive focus, such as RED-COLORED cat versus red-colored cat. Three adult native listeners perceptually scored the productions as correct or incorrect. The "correct" productions were then acoustically analyzed in terms of F0 range and duration.

RESULTS

Based on the perceptual scores, children with CIs produced focus with significantly lower accuracy (38%) than their TH peers (84%). The acoustic analysis on their "correct" productions showed that children with TH used both F0 and duration to mark focus, producing focal syllables with an expanded F0 range and long duration, and postfocal syllables with a reduced F0 range and short duration. However, children with CIs differed from children with TH in that they produced focal syllables with long duration but not an expanded F0 range, although they produced postfocal syllables with a reduced F0 range and short duration like their TH peers. In addition, early implantation correlated with the percept of more accurate focus productions and better use of F0 range in focal marking.

CONCLUSIONS

This study finds that Mandarin-speaking children with CIs are still learning to apply appropriate acoustic cues to contrastive focus. The challenge appears to lie in the use of an expanded F0 range to mark focus, probably related to the limited transmission of F0 information through the CI devices. These findings thus have implications for parents and those working with children with CIs, showing that utterance-level prosody also requires speech remediation, and underscores the critical role of identifying problems early in the acquisition of F0 functions in Mandarin, not only at the word level but also at the utterance-level.

Investigating Perception to Production Transfer in Children With Cochlear Implants: A High Variability Phonetic Training Study

PURPOSE

This study builds upon an established effective training method to investigate the advantages of high variability phonetic identification training for enhancing lexical tone perception and production in Mandarin-speaking pediatric cochlear implant (CI) recipients, who typically face ongoing challenges in these areas.

METHOD

Thirty-two Mandarin-speaking children with CIs were quasirandomly assigned into the training group (TG) and the control group (CG). The 16 TG participants received five sessions of high variability phonetic training (HVPT) within a period of 3 weeks. The CG participants did not receive the training. Perception and production of Mandarin tones were administered before (pretest) and immediately after (posttest) the completion of HVPT via lexical tone recognition task and picture naming task. Both groups participated in the identical pretest and posttest with the same time frame between the two test sessions.

RESULTS

TG showed significant improvement from pretest to posttest in identifying Mandarin tones for both trained and untrained speech stimuli. Moreover, perceptual learning of HVPT significantly facilitated trainees' production of T1 and T2 as rated by a cohort of 10 Mandarin-speaking adults with normal hearing, which was corroborated by acoustic analyses revealing improved fundamental frequency (F0) median for T1 and T2 production and enlarged F0 movement for T2 production. In contrast, TG children's production of T3 and T4 showed nonsignificant changes across two test sessions. Meanwhile, CG did not exhibit significant changes in either perception or production.

CONCLUSIONS

The results suggest a limited and inconsistent transfer of perceptual learning to lexical tone production in children with CIs, which challenges the notion of a robust transfer and highlights the complexity of the interaction between perceptual training and production outcomes. Further research on individual differences with a longitudinal design is needed to optimize the training protocol or tailor interventions to better meet the diverse needs of learners.

EEG-based assessment of temporal fine structure and envelope effect in mandarin syllable and tone perception

In recent years, speech perception research has benefited from low-frequency rhythm entrainment tracking of the speech envelope. However, speech perception is still controversial regarding the role of speech envelope and temporal fine structure, especially in Mandarin. This study aimed to discuss the dependence of Mandarin syllables and tones perception on the speech envelope and the temporal fine structure. We recorded the electroencephalogram (EEG) of the subjects under three acoustic conditions using the sound chimerism analysis, including (i) the original speech, (ii) the speech envelope and the sinusoidal modulation, and (iii) the fine structure of time and the modulation of the non-speech (white noise) sound envelope. We found that syllable perception mainly depended on the speech envelope, while tone perception depended on the temporal fine structure. The delta bands were prominent, and the parietal and prefrontal lobes were the main activated brain areas, regardless of whether syllable or tone perception was involved. Finally, we decoded the spatiotemporal features of Mandarin perception from the microstate sequence. The spatiotemporal feature sequence of the EEG caused by speech material was found to be specific, suggesting a new perspective for the subsequent auditory brain-computer interface. These results provided a new scheme for the coding strategy of new hearing aids for native Mandarin speakers.

HIGHLIGHTS

Production of Tone 2 in disyllabic words in Mandarin Chinese speaking children aged 3-5 with a cochlear implant and a contralateral hearing aid

To investigate Mandarin Tone 2 production of disyllabic words of prelingually deafened children with a cochlear implant (CI) and a contralateral hearing aid (HA) and to evaluate the relationship between their demographic variables and tone-production ability. Thirty prelingually Mandarin-speaking preschoolers with CI+HA and 30 age-matched normal-hearing (NH) children participated in the study. Fourteen disyllabic words were recorded from each child. A total of 840 tokens (14 × 60) were then used in tone-perception tests in which four speech therapists participated. The production of T2-related disyllabic words of the bimodal group was significantly worse than that of the NH group, as reflected in the overall accuracy (88.57% ± 16.31% vs 99.29% ± 21.79%, p < 0.05), the accuracy of T1+T2 (93.33% vs 100%), the accuracy of T2+T1 (66.67 ± 37.91% vs 98.33 ± 9.13%), and the accuracy of T2+T4 (78.33 ± 33.95% vs 100%). In addition, the bimodal group showed significantly inferior production accuracy of T2+T1 than T2+T2 and T3+T2, p < 0.05. Both bimodal age and implantation age were significantly negatively correlated with the overall production accuracy, p < 0.05. For the error patterns, bimodal participants experienced more errors when T2 was in the first position of the tone combination, and T2 was most likely to be mispronounced as T1 and T3. Bimodal patients aged 3-5 have T2-related disyllabic lexical tone production defects, and their performances are related to tone combination, implantation age, and bimodal age.

Sustainable Benefits of High Variability Phonetic Training in Mandarin-speaking Kindergarteners With Cochlear Implants: Evidence From Categorical Perception of Lexical Tones

OBJECTIVES

Although pitch reception poses a great challenge for individuals with cochlear implants (CIs), formal auditory training (e.g., high variability phonetic training [HVPT]) has been shown to provide direct benefits in pitch-related perceptual performances such as lexical tone recognition for CI users. As lexical tones in spoken language are expressed with a multitude of distinct spectral, temporal, and intensity cues, it is important to determine the sources of training benefits for CI users. The purpose of the present study was to conduct a rigorous fine-scale evaluation with the categorical perception (CP) paradigm to control the acoustic parameters and test the efficacy and sustainability of HVPT for Mandarin-speaking pediatric CI recipients. The main hypothesis was that HVPT-induced perceptual learning would greatly enhance CI users' ability to extract the primary pitch contours from spoken words for lexical tone identification and discrimination. Furthermore, individual differences in immediate and long-term gains from training would likely be attributable to baseline performance and duration of CI use.

DESIGN

Twenty-eight prelingually deaf Mandarin-speaking kindergarteners with CIs were tested. Half of them received five sessions of HVPT within a period of 3 weeks. The other half served as control who did not receive the formal training. Two classical CP tasks on a tonal continuum from Mandarin tone 1 (high-flat in pitch) to tone 2 (mid-rising in pitch) with fixed acoustic features of duration and intensity were administered before (pretest), immediately after (posttest), and 10 weeks posttraining termination (follow-up test). Participants were instructed to either label a speech stimulus along the continuum (i.e., identification task) or determine whether a pair of stimuli separated by zero or two steps from the continuum was the same or different (i.e., discrimination task). Identification function measures (i.e., boundary position and boundary width) and discrimination function scores (i.e., between-category score, within-category score, and peakedness score) were assessed for each child participant across the three test sessions.

RESULTS

Linear mixed-effects (LME) models showed significant training-induced enhancement in lexical tone categorization with significantly narrower boundary width and better between-category discrimination in the immediate posttest over pretest for the trainees. Furthermore, training-induced gains were reliably retained in the follow-up test 10 weeks after training. By contrast, no significant changes were found in the control group across sessions. Regression analysis confirmed that baseline performance (i.e., boundary width in the pretest session) and duration of CI use were significant predictors for the magnitude of training-induced benefits.

CONCLUSIONS

The stringent CP tests with synthesized stimuli that excluded acoustic cues other than the pitch contour and were never used in training showed strong evidence for the efficacy of HVPT in yielding immediate and sustained improvement in lexical tone categorization for Mandarin-speaking children with CIs. The training results and individual differences have remarkable implications for developing personalized computer-based short-term HVPT protocols that may have sustainable long-term benefits for aural rehabilitation in this clinical population.

Lexical Access in Preschool Mandarin-Speaking Children With Cochlear Implants

PURPOSE

Children with cochlear implants (CIs) have less experience accessing spoken language. Mandarin Chinese uses pitch information to contrast word meaning, and the signal that the CI devices provide is degraded. Thus, Mandarin-speaking children with CIs may face more challenges in the development of language skills. This study examines preschool Mandarin-speaking children's performance in lexical access. We hypothesized that children with CIs and their peers with normal hearing (NH) have comparable naming ability, but they process phonological or semantic information differently.

METHOD

Twenty children with CIs and 20 age-matched children with NH were tested. The cross-modal visual-auditory picture-word interference paradigm was applied. The distractor was either phonologically related (mao⁵⁵ cat -mao⁵¹ hat), semantically related (mao⁵⁵ cat -shu²¹⁴ mouse) or unrelated (mao⁵⁵ cat -zhi²¹⁴ paper) to the target, and it was aurally presented at four different points in time relative to the picture. Accuracy was compared between the two groups to tap into the children's naming abilities, and reaction time was analyzed to examine the effects of phonological and semantic information.

RESULTS

No group difference in accuracy was found. The phonologically related distractors led to significantly higher accuracy scores and shorter reaction times, whereas the semantically related distractors did not. Unlike the NH group, the CI group did not respond significantly faster or slower in phonologically related condition when the distractor and picture occurred simultaneously. Finally, the CI group made overall quicker responses than the NH group.

CONCLUSIONS

Children with CIs are as successful as children with NH in word retrieval and production, and the two groups both show phonological priming effect and lack semantic effect. However, children with CIs do not process phonological information as early as their NH peers, and they may be more tasks directed and hence make quicker responses.

Acoustic analysis of tone production in Mandarin-speaking bimodal cochlear implant users

The benefit of using a hearing aid with a cochlear implant (bimodal hearing) has been demonstrated for tone perception under certain conditions. The present study evaluated bimodal effects for tone production by comparing performance between a bimodal and a unimodal implant group. Results showed that acoustic differentiation of tones produced by the bimodal group was better than the unimodal implant group, and performance was dependent on the subject's acoustic thresholds but not related to implant experience or age at implantation. The findings support the use of amplified acoustic hearing in conjunction with the implant for better development of pitch production.

Voice emotion recognition by Mandarin-speaking pediatric cochlear implant users in Taiwan

OBJECTIVES

To explore the effects of obligatory lexical tone learning on speech emotion recognition and the cross-culture differences between United States and Taiwan for speech emotion understanding in children with cochlear implant.

METHODS

This cohort study enrolled 60 cochlear-implanted (cCI) Mandarin-speaking, school-aged children who underwent cochlear implantation before 5 years of age and 53 normal-hearing children (cNH) in Taiwan. The emotion recognition and the sensitivity of fundamental frequency (F0) changes for those school-aged cNH and cCI (6-17 years old) were examined in a tertiary referred center.

RESULTS

The mean emotion recognition score of the cNH group was significantly better than the cCI. Female speakers' vocal emotions are more easily to be recognized than male speakers' emotion. There was a significant effect of age at test on voice recognition performance. The average score of cCI with full-spectrum speech was close to the average score of cNH with eight-channel narrowband vocoder speech. The average performance of voice emotion recognition across speakers for cCI could be predicted by their sensitivity to changes in F0.

CONCLUSIONS

Better pitch discrimination ability comes with better voice emotion recognition for Mandarin-speaking cCI. Besides the F0 cues, cCI are likely to adapt their voice emotion recognition by relying more on secondary cues such as intensity and duration. Although cross-culture differences exist for the acoustic features of voice emotion, Mandarin-speaking cCI and their English-speaking cCI peer expressed a positive effect for age at test on emotion recognition, suggesting the learning effect and brain plasticity. Therefore, further device/processor development to improve presentation of pitch information and more rehabilitative efforts are needed to improve the transmission and perception of voice emotion in Mandarin.

LEVEL OF EVIDENCE

3.

Pitch Accuracy of Vocal Singing in Deaf Children With Bimodal Hearing and Bilateral Cochlear Implants

OBJECTIVES

The purpose of the present study was to investigate the pitch accuracy of vocal singing in children with severe to profound hearing loss who use bilateral cochlear implants (CIs) or bimodal devices [CI at one ear and hearing aid (HA) at the other] in comparison to similarly-aged children with normal-hearing (NH).

DESIGN

The participants included four groups: (1) 26 children with NH, (2) 13 children with bimodal devices, (3) 31 children with bilateral CIs that were implanted sequentially, and (4) 10 children with bilateral CIs that were implanted simultaneously. All participants were aged between 7 and 11 years old. Each participant was recorded singing a self-chosen song that was familiar to him or her. The fundamental frequencies (F0) of individual sung notes were extracted and normalized to facilitate cross-subject comparisons. Pitch accuracy was quantified using four pitch-based metrics calculated with reference to the target music notes: mean note deviation, contour direction, mean interval deviation, and F0 variance ratio. A one-way ANOVA was used to compare listener-group difference on each pitch metric. A principal component analysis showed that the mean note deviation best accounted for pitch accuracy in vocal singing. A regression analysis examined potential predictors of CI children's singing proficiency using mean note deviation as the dependent variable and demographic and audiological factors as independent variables.

RESULTS

The results revealed significantly poorer performance on all four pitch-based metrics in the three groups of children with CIs in comparison to children with NH. No significant differences were found among the three CI groups. Among the children with CIs, variability in the vocal singing proficiency was large. Within the group of 13 bimodal users, the mean note deviation was significantly correlated with their unaided pure-tone average thresholds (r = 0.582, p = 0.037). The regression analysis for all children with CIs, however, revealed no significant demographic or audiological predictor for their vocal singing performance.

CONCLUSION

Vocal singing performance in children with bilateral CIs or bimodal devices is not significantly different from each other on a group level. Compared to children with NH, the pediatric bimodal and bilateral CI users, in general, demonstrated significant deficits in vocal singing ability. Demographic and audiological factors, known from previous studies to be associated with good speech and language development in prelingually-deafened children with CIs, were not associated with singing accuracy for these children.

Speech production in Mandarin-speaking children with cochlear implants: a systematic review

OBJECTIVE

This study aimed to systematically review and critically appraise the literature describing the phonetic characteristics and accuracy of the consonants, vowels and tones produced by Mandarin-speaking children with cochlear implants (CIs).

DESIGN

The protocol in this review was designed in conformity with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. EBSCOhost, PubMed, Scopus, PsycINFO, ProQuest Central databases were searched for relevant articles which met the inclusion criteria.

STUDY SAMPLE

A total of 18 journal papers were included in this review.

RESULTS

The results revealed that Mandarin-speaking children with CIs perform consistently more poorly in their production of consonants, in particular on fricatives, have a smaller and less well-defined vowel space, and exhibit greater difficulties in tone realisation, notably T2 and T3, when compared to their normal-hearing (NH) peers. The results from acoustic and accuracy analyses are negatively correlated with CI implantation age, but largely positively correlated with hearing age.

CONCLUSIONS

Findings of this review highlight the factors that influence consonant, vowel and tone production in Mandarin-speaking children with CIs, thereby providing critical information for clinicians and researchers working with this population.

Mandarin tone recognition training with cochlear implant simulation: Amplitude envelope enhancement and cue weighting

With limited fundamental frequency (F0) cues, cochlear implant (CI) users recognize Mandarin tones using amplitude envelope. This study investigated whether tone recognition training with amplitude envelope enhancement may improve tone recognition and cue weighting with CIs. Three groups of CI-simulation listeners received training using vowels with amplitude envelope modified to resemble F0 contour (enhanced-amplitude-envelope training), training using natural vowels (natural-amplitude-envelope training), and exposure to natural vowels without training, respectively. Tone recognition with natural and enhanced amplitude envelope cues and cue weighting of amplitude envelope and F0 contour were measured in pre-, post-, and retention-tests. It was found that with similar pre-test performance, both training groups had better tone recognition than the no-training group after training. Only enhanced-amplitude-envelope training increased the benefits of amplitude envelope enhancement in the post- and retention-tests than in the pre-test. Neither training paradigm increased the cue weighting of amplitude envelope and F0 contour more than stimulus exposure. Listeners attending more to amplitude envelope in the pre-test tended to have better tone recognition with enhanced amplitude envelope cues before training and improve more in tone recognition after enhanced-amplitude-envelope training. The results suggest that auditory training and speech enhancement may bring maximum benefits to CI users when combined.

Perception of Child-Directed Versus Adult-Directed Emotional Speech in Pediatric Cochlear Implant Users

OBJECTIVES

Cochlear implants (CIs) are remarkable in allowing individuals with severe to profound hearing loss to perceive speech. Despite these gains in speech understanding, however, CI users often struggle to perceive elements such as vocal emotion and prosody, as CIs are unable to transmit the spectro-temporal detail needed to decode affective cues. This issue becomes particularly important for children with CIs, but little is known about their emotional development. In a previous study, pediatric CI users showed deficits in voice emotion recognition with child-directed stimuli featuring exaggerated prosody. However, the large intersubject variability and differential developmental trajectory known in this population incited us to question the extent to which exaggerated prosody would facilitate performance in this task. Thus, the authors revisited the question with both adult-directed and child-directed stimuli.

DESIGN

Vocal emotion recognition was measured using both child-directed (CDS) and adult-directed (ADS) speech conditions. Pediatric CI users, aged 7-19 years old, with no cognitive or visual impairments and who communicated through oral communication with English as the primary language participated in the experiment (n = 27). Stimuli comprised 12 sentences selected from the HINT database. The sentences were spoken by male and female talkers in a CDS or ADS manner, in each of the five target emotions (happy, sad, neutral, scared, and angry). The chosen sentences were semantically emotion-neutral. Percent correct emotion recognition scores were analyzed for each participant in each condition (CDS vs. ADS). Children also completed cognitive tests of nonverbal IQ and receptive vocabulary, while parents completed questionnaires of CI and hearing history. It was predicted that the reduced prosodic variations found in the ADS condition would result in lower vocal emotion recognition scores compared with the CDS condition. Moreover, it was hypothesized that cognitive factors, perceptual sensitivity to complex pitch changes, and elements of each child's hearing history may serve as predictors of performance on vocal emotion recognition.

RESULTS

Consistent with our hypothesis, pediatric CI users scored higher on CDS compared with ADS speech stimuli, suggesting that speaking with an exaggerated prosody-akin to "motherese"-may be a viable way to convey emotional content. Significant talker effects were also observed in that higher scores were found for the female talker for both conditions. Multiple regression analysis showed that nonverbal IQ was a significant predictor of CDS emotion recognition scores while Years using CI was a significant predictor of ADS scores. Confusion matrix analyses revealed a dependence of results on specific emotions; for the CDS condition's female talker, participants had high sensitivity (d' scores) to happy and low sensitivity to the neutral sentences while for the ADS condition, low sensitivity was found for the scared sentences.

CONCLUSIONS

In general, participants had higher vocal emotion recognition to the CDS condition which also had more variability in pitch and intensity and thus more exaggerated prosody, in comparison to the ADS condition. Results suggest that pediatric CI users struggle with vocal emotion perception in general, particularly to adult-directed speech. The authors believe these results have broad implications for understanding how CI users perceive emotions both from an auditory communication standpoint and a socio-developmental perspective.

High-Variability Phonetic Training Benefits Lexical Tone Perception: An Investigation on Mandarin-Speaking Pediatric Cochlear Implant Users

Purpose Lexical tone perception is known to be persistently difficult for individuals with cochlear implants (CIs). The purpose of this study was to evaluate the efficacy of high-variability phonetic training (HVPT) in improving Mandarin tone perception for native-speaking children with CIs. Method A total of 28 Mandarin-speaking pediatric CI recipients participated in the study. Half of the children with CIs received a five-session HVPT within a period of 3 weeks. Identification and discrimination of lexical tones produced by familiar talkers (used during training) and novel talkers (not used during training) were measured before, immediately after, and 10 weeks after training termination. The other half untrained children served as control for the identical pre- and posttests. Results Lexical tone perception significantly improved in both trained identification task and untrained discrimination task for the trainees. There was also a significant effect in transfer of learning to perceiving tones produced by novel talkers. Moreover, training-induced gains were retained for up to 10 weeks after training. By comparison, no significant pre-post changes were observed in the control group. Conclusion The results provide the first systematical assessment for the efficacy of the HVPT protocol for Mandarin-speaking pediatric CI users with congenital hearing loss, which supports the clinical utility of intensive short-term HVPT in these children's rehabilitative regimens.

Bimodal Benefits Revealed by Categorical Perception of Lexical Tones in Mandarin-Speaking Kindergarteners With a Cochlear Implant and a Contralateral Hearing Aid

Purpose Pitch reception poses challenges for individuals with cochlear implants (CIs), and adding a hearing aid (HA) in the nonimplanted ear is potentially beneficial. The current study used fine-scale synthetic speech stimuli to investigate the bimodal benefit for lexical tone categorization in Mandarin-speaking kindergarteners using a CI and an HA in opposite ears. Method The data were collected from 16 participants who were required to complete two classical tasks for speech categorical perception (CP) with CI + HA device condition and CI alone condition. Linear mixed-effects models were constructed to evaluate the identification and discrimination scores across different device conditions. Results The bimodal kindergarteners showed CP for the continuum varying from Mandarin Tone 1 and Tone 2. Moreover, the additional acoustic information from the contralateral HA contributes to improved lexical tone categorization, with a steeper slope, a higher discrimination score of between-category stimuli pair, and an improved peakedness score (i.e., an increased benefit magnitude for discriminations of between-category over within-category pairs) for the CI + HA condition than the CI alone condition. The bimodal kindergarteners with better residual hearing thresholds at 250 Hz level in the nonimplanted ear could perceive lexical tones more categorically. Conclusion The enhanced CP results with bimodal listening provide clear evidence for the clinical practice to fit a contralateral HA in the nonimplanted ear in kindergarteners with unilateral CIs with direct benefits from the low-frequency acoustic hearing.

Acoustic Assessment of Tone Production of Prelingually-Deafened Mandarin-Speaking Children With Cochlear Implants

Objective

The purpose of the present study was to investigate Mandarin tone production performance of prelingually deafened children with cochlear implants (CIs) using modified acoustic analyses and to evaluate the relationship between demographic factors of those CI children and their tone production ability.

Methods

Two hundred seventy-eight prelingually deafened children with CIs and 173 age-matched normal-hearing (NH) children participated in the study. Thirty-six monosyllabic Mandarin Chinese words were recorded from each subject. The fundamental frequencies (F0) were extracted from the tone tokens. Two acoustic measures (i.e., differentiability and hit rate) were computed based on the F0 onset and offset values (i.e., the tone ellipses of the two-dimensional [2D] method) or the F0 onset, midpoint, and offset values (i.e., the tone ellipsoids of the 3D method). The correlations between the acoustic measures as well as between the methods were performed. The relationship between demographic factors and acoustic measures were also explored.

Results

The children with CIs showed significantly poorer performance in tone differentiability and hit rate than the NH children. For both CI and NH groups, performance on the two acoustic measures was highly correlated with each other (r values: 0.895–0.961). The performance between the two methods (i.e., 2D and 3D methods) was also highly correlated (r values: 0.774–0.914). Age at implantation and duration of CI use showed a weak correlation with the scores of acoustic measures under both methods. These two factors jointly accounted for 15.4–18.9% of the total variance of tone production performance.

Conclusion

There were significant deficits in tone production ability in most prelingually deafened children with CIs, even after prolonged use of the devices. The strong correlation between the two methods suggested that the simpler, 2D method seemed to be efficient in acoustic assessment for lexical tones in hearing-impaired children. Age at implantation and especially the duration of CI use were significant, although weak, predictors for tone development in pediatric CI users. Although a large part of tone production ability could not be attributed to these two factors, the results still encourage early implantation and continual CI use for better lexical tone development in Mandarin-speaking pediatric CI users.

How Vocal Emotions Produced by Children With Cochlear Implants Are Perceived by Their Hearing Peers

Purpose Cochlear implants (CIs) transmit a degraded version of the acoustic input to the listener. This impacts the perception of harmonic pitch, resulting in deficits in the perception of voice features critical to speech prosody. Such deficits may relate to changes in how children with CIs (CCIs) learn to produce vocal emotions. The purpose of this study was to investigate happy and sad emotional speech productions by school-age CCIs, compared to productions by children with normal hearing (NH), postlingually deaf adults with CIs, and adults with NH. Method All individuals recorded the same emotion-neutral sentences in a happy manner and a sad manner. These recordings were then used as stimuli in an emotion recognition task performed by child and adult listeners with NH. Their performance was taken as a measure of how well the 4 groups of talkers communicated the 2 emotions. Results Results showed high variability in the identifiability of emotions produced by CCIs, relative to other groups. Some CCIs produced highly identifiable emotions, while others showed deficits. The postlingually deaf adults with CIs produced highly identifiable emotions and relatively small intersubject variability. Age at implantation was found to be a significant predictor of performance by CCIs. In addition, the NH listeners' age predicted how well they could identify the emotions produced by CCIs. Thus, older NH child listeners were better able to identify the CCIs' intended emotions than younger NH child listeners. In contrast to the deficits in their emotion productions, CCIs produced highly intelligible words in the sentences carrying the emotions. Conclusions These results confirm previous findings showing deficits in CCIs' productions of prosodic cues and indicate that early auditory experience plays an important role in vocal emotion productions by individuals with CIs.