The effect of lexical tone experience on English intonation perception in Mandarin-speaking cochlear-implanted children.

To examine the effect of lexical tone experience on English intonation perception in Mandarin-speaking cochlear-implanted children during second language acquisition in Taiwan. A retrospective cohort study. A tertiary referred center. Fourteen children with cochlear implant (CI) in the experimental group, and 9 normal hearing children in the control group were enrolled in this study. Cochlear implantation and hearing rehabilitation. Two speech recognition accuracies were examined: (1) Lexical tone recognition (4-alternative forced choice, AFC), (2) English Sentence Intonation (2AFC). The overall accuracies for tone perception are 61.13% (standard deviation, SD = 10.84%) for CI group and 93.82% (SD = 1.80%) for normal hearing group. Tone 4 and Tone 1 were more easily to be recognized than tone 2 and tone 3 in the pediatric CI recipients (cCI) group. In English intonation perception, the overall accuracies are 61.82% (SD = 16.85%) for CI group, and 97.59% (SD = 4.73%) for normal hearing group. Significant high correlation (R = .919, P ≦ .000) between lexical tone perception and English intonation perception is noted. There is no significant difference for English intonation perception accuracies between Mandarin-speaking cCI (61.82%) and English-speaking cCI (70.13%, P = .11). Mandarin-speaking cochlear-implanted children showed significant deficits in perception of lexical tone and English intonation relative to normal hearing children. There was no tonal language benefit in Mandarin-speaking cochlear-implanted children's English intonation perception, compared to the English-speaking cochlear-implanted peers. For cochlear-implanted children, better lexical tone perception comes with better English intonation perception. Enhancing Mandarin prosodic perception for cochlear-implanted children may benefit their command of intonation in English.

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.

Effects of cooperating and conflicting cues on speech intonation recognition by cochlear implant users and normal hearing listeners.

Cochlear implant (CI) recipients have only limited access to fundamental frequency (F0) information, and thus exhibit deficits in speech intonation recognition. For speech intonation, F0 serves as the primary cue, and other potential acoustic cues (e.g. intensity properties) may also contribute. This study examined the effects of cooperating or conflicting acoustic cues on speech intonation recognition by adult CI and normal hearing (NH) listeners with full-spectrum and spectrally degraded speech stimuli. Identification of speech intonation that signifies question and statement contrasts was measured in 13 CI recipients and 4 NH listeners, using resynthesized bi-syllabic words, where F0 and intensity properties were systematically manipulated. The stimulus set was comprised of tokens whose acoustic cues (i.e. F0 contour and intensity patterns) were either cooperating or conflicting. Subjects identified if each stimulus is a 'statement' or a 'question' in a single-interval, 2-alternative forced-choice (2AFC) paradigm. Logistic models were fitted to the data, and estimated coefficients were compared under cooperating and conflicting conditions, between the subject groups (CI vs. NH), and under full-spectrum and spectrally degraded conditions for NH listeners. The results indicated that CI listeners' intonation recognition was enhanced by cooperating F0 contour and intensity cues, but was adversely affected by these cues being conflicting. On the other hand, with full-spectrum stimuli, NH listeners' intonation recognition was not affected by cues being cooperating or conflicting. The effects of cues being cooperating or conflicting were comparable between the CI group and NH listeners with spectrally degraded stimuli. These findings suggest the importance of taking multiple acoustic sources for speech recognition into consideration in aural rehabilitation for CI recipients.

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

Purpose: This study examined the utilization of multiple types of acoustic information in lexical tone production and perception by pediatric cochlear implant (CI) recipients who are native speakers of Mandarin Chinese. Methods: Lexical tones were recorded from CI recipients and their peers with normal hearing (NH). Each participant was asked to produce a disyllabic word, yan jing, with which the first syllable was pronounced as Tone 3 (a low dipping tone) while the second syllable was pronounced as Tone 1 (a high level tone, meaning "eyes") or as Tone 4 (a high falling tone, meaning "eyeglasses"). In addition, a parametric manipulation in fundamental frequency (F0) and duration of Tones 1 and 4 used in a lexical tone recognition task in Peng et al. (2017) was adopted to evaluate the perceptual reliance on each dimension. Results: Mixed-effect analyses of duration, intensity, and F0 cues revealed that NH children focused exclusively on marking distinct F0 contours, while CI participants shortened Tone 4 or prolonged Tone 1 to enhance their contrast. In line with these production strategies, NH children relied primarily on F0 cues to identify the two tones, whereas CI children showed greater reliance on duration cues. Moreover, CI participants who placed greater perceptual weight on duration cues also tended to exhibit smaller changes in their F0 production. Conclusion: Pediatric CI recipients appear to contrast the secondary acoustic dimension (duration) in addition to F0 contours for both lexical tone production and perception. These findings suggest that perception and production strategies of lexical tones are well coupled in this pediatric CI population.

A tonal-language benefit for pitch in normally-hearing and cochlear-implanted children.

In tonal languages, voice pitch inflections change the meaning of words, such that the brain processes pitch not merely as an acoustic characterization of sound but as semantic information. In normally-hearing (NH) adults, this linguistic pressure on pitch appears to sharpen its neural encoding and can lead to perceptual benefits, depending on the task relevance, potentially generalizing outside of the speech domain. In children, however, linguistic systems are still malleable, meaning that their encoding of voice pitch information might not receive as much neural specialization but might generalize more easily to ecologically irrelevant pitch contours. This would seem particularly true for early-deafened children wearing a cochlear implant (CI), who must exhibit great adaptability to unfamiliar sounds as their sense of pitch is severely degraded. Here, we provide the first demonstration of a tonal language benefit in dynamic pitch sensitivity among NH children (using both a sweep discrimination and labelling task) which extends partially to children with CI (i.e., in the labelling task only). Strong age effects suggest that sensitivity to pitch contours reaches adult-like levels early in tonal language speakers (possibly before 6 years of age) but continues to develop in non-tonal language speakers well into the teenage years. Overall, we conclude that language-dependent neuroplasticity can enhance behavioral sensitivity to dynamic pitch, even in extreme cases of auditory degradation, but it is most easily observable early in life.

Processing F0 with cochlear implants: Modulation frequency discrimination and speech intonation recognition.

Fundamental frequency (F0) processing by cochlear implant (CI) listeners was measured using a psychophysical task and a speech intonation recognition task. Listeners' Weber fractions for modulation frequency discrimination were measured using an adaptive, 3-interval, forced-choice paradigm: stimuli were presented through a custom research interface. In the speech intonation recognition task, listeners were asked to indicate whether resynthesized bisyllabic words, when presented in the free field through the listeners' everyday speech processor, were question-like or statement-like. The resynthesized tokens were systematically manipulated to have different initial-F0s to represent male vs. female voices, and different F0 contours (i.e. falling, flat, and rising) Although the CI listeners showed considerable variation in performance on both tasks, significant correlations were observed between the CI listeners' sensitivity to modulation frequency in the psychophysical task and their performance in intonation recognition. Consistent with their greater reliance on temporal cues, the CI listeners' performance in the intonation recognition task was significantly poorer with the higher initial-F0 stimuli than with the lower initial-F0 stimuli. Similar results were obtained with normal hearing listeners attending to noiseband-vocoded CI simulations with reduced spectral resolution.

Long-term trajectories of the development of speech sound production in pediatric cochlear implant recipients.

PURPOSE: This study characterized the development of speech sound production in prelingually deaf children with a minimum of 8 years of cochlear implant (CI) experience. METHOD: Twenty-seven pediatric CI recipients' spontaneous speech samples from annual evaluation sessions were phonemically transcribed. Accuracy for these speech samples was evaluated in piecewise regression models. RESULTS: As a group, pediatric CI recipients showed steady improvement in speech sound production following implantation, but the improvement rate declined after 6 years of device experience. Piecewise regression models indicated that the slope estimating the participants' improvement rate was statistically greater than 0 during the first 6 years postimplantation, but not after 6 years. The group of pediatric CI recipients' accuracy of speech sound production after 4 years of device experience reasonably predicts their speech sound production after 5-10 years of device experience. CONCLUSIONS: The development of speech sound production in prelingually deaf children stabilizes after 6 years of device experience, and typically approaches a plateau by 8 years of device use. Early growth in speech before 4 years of device experience did not predict later rates of growth or levels of achievement. However, good predictions could be made after 4 years of device use.

Continuous improvement in Mandarin lexical tone perception as the number of channels increased: a simulation study of cochlear implant.

CONCLUSION: With reference to English phoneme recognition, where performance usually does not improve after six or eight channels in cochlear implants (CIs), increasing total channel numbers continuously improved perception of Mandarin tones. OBJECTIVE: To test our hypothesis that current CI strategies might be modified to improve Mandarin lexical tonal perception. MATERIALS AND METHODS: Lexical tonal perception tests using 48 monosyllables in Mandarin Chinese were conducted in 32 native Mandarin speakers with normal hearing. The performance of tonal perception was compared among the controlled factors, which were total channel number, number of channels allocated to the F0 spectrum, and whether there were spectral shifts in the electrode configuration. The experimental condition that preserves fine structure was used as a comparison. RESULTS: The signal processing strategy using 16 channels--which is technically possible with current CI devices--produced better tonal perception than those using 12 or 8 channels. Increasing the number of fundamental channels did not improve tonal perception, and spectral shifts did not change tonal perception. An experimental condition (FiC12) that preserves the fine structure produced significantly better overall scores for tone perception than other experimental conditions with envelope strategies.

Imitative production of rising speech intonation in pediatric cochlear implant recipients.

PURPOSE: This study investigated the acoustic characteristics of pediatric cochlear implant (CI) recipients' imitative production of rising speech intonation, in relation to the perceptual judgments by listeners with normal hearing (NH). METHOD: Recordings of a yes-no interrogative utterance imitated by 24 prelingually deafened children with a CI were extracted from annual evaluation sessions. These utterances were perceptually judged by adult NH listeners in regard with intonation contour type (non-rise, partial-rise, or full-rise) and contour appropriateness (on a 5-point scale). Fundamental frequency, intensity, and duration properties of each utterance were also acoustically analyzed. RESULTS: Adult NH listeners' judgments of intonation contour type and contour appropriateness for each CI participant's utterances were highly positively correlated. The pediatric CI recipients did not consistently use appropriate intonation contours when imitating a yes-no question. Acoustic properties of speech intonation produced by these individuals were discernible among utterances of different intonation contour types according to NH listeners' perceptual judgments. CONCLUSIONS: These findings delineated the perceptual and acoustic characteristics of speech intonation imitated by prelingually deafened children and young adults with a CI. Future studies should address whether the degraded signals these individuals perceive via a CI contribute to their difficulties with speech intonation production.

Processing of Acoustic Cues in Lexical-Tone Identification by Pediatric Cochlear-Implant Recipients.

Purpose: The objective was to investigate acoustic cue processing in lexical-tone recognition by pediatric cochlear-implant (CI) recipients who are native Mandarin speakers. Method: Lexical-tone recognition was assessed in pediatric CI recipients and listeners with normal hearing (NH) in 2 tasks. In Task 1, participants identified naturally uttered words that were contrastive in lexical tones. For Task 2, a disyllabic word (yanjing) was manipulated orthogonally, varying in fundamental-frequency (F0) contours and duration patterns. Participants identified each token with the second syllable jing pronounced with Tone 1 (a high level tone) as eyes or with Tone 4 (a high falling tone) as eyeglasses. Results: CI participants' recognition accuracy was significantly lower than NH listeners' in Task 1. In Task 2, CI participants' reliance on F0 contours was significantly less than that of NH listeners; their reliance on duration patterns, however, was significantly higher than that of NH listeners. Both CI and NH listeners' performance in Task 1 was significantly correlated with their reliance on F0 contours in Task 2. Conclusion: For pediatric CI recipients, lexical-tone recognition using naturally uttered words is primarily related to their reliance on F0 contours, although duration patterns may be used as an additional cue.

Comparison of Demographic Parameters and Predation Rates of Orius strigicollis (Hemiptera: Anthocoridae) Fed on Eggs of Tetranychus urticae (Acari: Tetranychidae) and Cadra cautella (Lepidoptera: Pyralidae).

Orius strigicollis (Poppius) is an anthocorid bug with high foraging ability on thrips as well as on mites, and the bug has been considered as a potential biological control agent in Taiwan. Life table and predation studies of O. strigicollis fed on Cadra cautella (Walker) and Tetranychus urticae (Koch) eggs were conducted at 25 ± 1°C. Data were analyzed and compared using TWOSEX-MSChart and CONSUME-MSChart software. O. strigicollis fed on eggs of C. cautella, a substitute prey, showed significantly higher survival rate and developmental rate than individuals fed on their natural prey, T. urticae eggs. The fecundity of O. strigicollis fed on C. cautella eggs was, on average, 13.2 times higher than that of those fed on T. urticae eggs, despite of the fact that during the entire nymphal stage, the consumption rate of O. strigicollis on T. urticae eggs was ca. 9 times higher than on almond moth eggs The conversion rate (i.e., number of prey eggs needed to produce one predator egg) for this predatory bug reared on T. urticae eggs and almond moth eggs were 604.6 and 6.0, respectively, indicating that almond moth eggs served as an effective alternative prey for ensuring the predator's reproduction. This is the first study pertaining to the population parameters and predation rates of O. strigicollis using the age-stage two-sex approach to describe differences between O. strigicollis populations reared on natural and alternative preys. This information may be useful in mass rearing programs and field application involving this biological control agent.

Consonant production and language skills in Mandarin-speaking children with cochlear implants.

OBJECTIVES: To investigate the phonemic inventories of syllable-initial consonants in Mandarin-speaking children with cochlear implants, assessing the relationship between the children's mastery levels of consonant production and their receptive and expressive language skills. DESIGN: Descriptive study. SETTING: Chi-Mei Medical Center, Tainan, Taiwan. PATIENTS: The 30 prelingually deaf children with cochlear implants who participated in the study ranged in age from 6 years to 12 years 6 months, and their age at implantation ranged from 2 years 3 months to 10 years 3 months. The average length of device experience was 3 years 7 months (range, 1 year 7 months to 6 years 5 months). None of the children was identified with concomitant learning disabilities. OUTCOME MEASURES: The 21 Mandarin syllable-initial consonants were elicited using a set of 105 pictures. Two language assessment tools were used to evaluate the children's receptive vocabulary skills as well as their overall receptive and expressive language development. RESULTS: The mean +/- SD score for correct consonant production was 57.9% +/- 19.5%. Regarding the manner of articulation, plosives received the highest average correct percentage whereas nasals, affricates, fricatives, and the lateral approximant /l/ were less frequently correct. The children's overall percentage of correct scores for consonant production and receptive vocabulary measure were significantly correlated (r = 0.51; P =.005). Additionally, correlation coefficients were significant between the overall score for correct consonant production and both the scores for receptive language measure (r = 0.65; P<.001) and expressive language measure (r = 0.76; P<.001). The participants' consonant production skills were negatively correlated with age at implantation (r = - 0.46; P =.01) and positively correlated with length of experience with cochlear implant (r = 0.45; P =.02). CONCLUSIONS: Mastery levels of Mandarin syllable-initial consonants remained moderately low in prelingually deaf children with cochlear implants. The present results suggest a significant association between consonant production skills and language development in these children.

Acquisition profiles of syllable-initial consonants in Mandarin-speaking children with cochlear implants.

OBJECTIVES: To examine the production and discrimination skills of Mandarin initial-consonant syllables in children with cochlear implants (CIs), as a function of both age at implantation and length of CI experience. In addition, we also aimed to evaluate the relationship between these children's perception and production profiles. MATERIAL AND METHODS: Thirty prelingually deaf children aged between 6 years 0 months and 12 years 6 months who received their implants between the ages of 2 years 3 months and 10 years 3 months participated. The ability of the children to produce the 21 Mandarin initial-consonant syllables were elicited using a set of 105 pictures. In addition, the 21 consonants were arranged into 16 minimal pairs to determine the children's discrimination skills by asking them to accurately identify the target consonants. RESULTS: The children's mean accurate consonant production score was 57.9% (SD 19.5%) and the average correct consonant discrimination score was 76.67% (SD 11.18%), which was significantly higher than the 50% chance level [t(29) = 13.07: p < 0.001]. There were significant negative correlations between the performance level of consonant production and both age at implantation and length of CI experience. Children who received their implants at a younger age (< 6 years) tended to demonstrate an acquisition profile similar to that of children with normal hearing, i.e. the production and perception skills tended toward near-synchronization, and the mastery of production slightly preceded that of perception. CONCLUSION: This report demonstrates that early implantation is associated with a near-synchronous acquisition profile of the production and discrimination of Mandarin consonants, which is similar to that of normal-hearing children at a younger age. Specifically, early implantation can promote children's production skills of Mandarin initial-consonant syllables.

Speech intelligibility of pediatric cochlear implant recipients with 7 years of device experience.

Speech intelligibility of 24 prelingually deaf pediatric cochlear implant (CI) recipients with 84 months of device experience was investigated. Each CI participant's speech samples were judged by a panel of 3 listeners. Intelligibility scores were calculated as the average of the 3 listeners' responses. The average write-down intelligibility score was 71.54% (SD = 29.89), and the average rating-scale intelligibility score was 3.03 points (SD = 1.01). Write-down and rating-scale intelligibility scores were highly correlated (r = .91, p < .001). Linear regression analyses revealed that both age at implantation and different speech-coding strategies contribute to the variability of CI participants' speech intelligibility. Implantation at a younger age and the use of the spectral-peak speech-coding strategy yielded higher intelligibility scores than implantation at an older age and the use of the multipeak speech-coding strategy. These results serve as indices for clinical applications when long-term advancements in spoken-language development are considered for pediatric CI recipients.

Acoustic cue integration in speech intonation recognition with cochlear implants.

The present article reports on the perceptual weighting of prosodic cues in question-statement identification by adult cochlear implant (CI) listeners. Acoustic analyses of normal-hearing (NH) listeners' production of sentences spoken as questions or statements confirmed that in English the last bisyllabic word in a sentence carries the dominant cues (F0, duration, and intensity patterns) for the contrast. Furthermore, these analyses showed that the F0 contour is the primary cue for the question-statement contrast, with intensity and duration changes conveying important but less reliable information. On the basis of these acoustic findings, the authors examined adult CI listeners' performance in two question-statement identification tasks. In Task 1, 13 CI listeners' question-statement identification accuracy was measured using naturally uttered sentences matched for their syntactic structures. In Task 2, the same listeners' perceptual cue weighting in question-statement identification was assessed using resynthesized single-word stimuli, within which fundamental frequency (F0), intensity, and duration properties were systematically manipulated. Both tasks were also conducted with four NH listeners with full-spectrum and noise-band-vocoded stimuli. Perceptual cue weighting was assessed by comparing the estimated coefficients in logistic models fitted to the data. Of the 13 CI listeners, 7 achieved high performance levels in Task 1. The results of Task 2 indicated that multiple sources of acoustic cues for question-statement identification were utilized to different extents depending on the listening conditions (e.g., full spectrum vs. spectrally degraded) or the listeners' hearing and amplification status (e.g., CI vs. NH).

Effects of frequency allocation on lexical tone identification by Mandarin-speaking children with a cochlear implant.

CONCLUSION: Frequency allocation with extended frequency ranges yielded significantly higher accuracy in pediatric CI recipients' lexical tone identification. These findings suggest that frequency allocation with extended frequency ranges may be useful in improving lexical tone recognition for at least some pediatric CI recipients. OBJECTIVES: To assess the effects of frequency allocation on lexical tone identification by Mandarin-speaking children with a cochlear implant (CI). SUBJECTS AND METHODS: In a prospective study, 15 prelingually deafened children between 7.17 and 16.17 years of age served as participants. Using Med-el CI devices, each participant's accuracy in lexical tone identification was compared in two conditions: first, the experimental condition, i.e. use of the extended frequency range from 233 to 8501 Hz; second, the control condition, i.e. use of the participant's clinically assigned frequency range from 300 to 8404 Hz. RESULTS: The group mean of pediatric CI users' accuracy in lexical tone identification was 88.02% (SD = 6.31%) in the experimental condition and 83.82% (SD = 9.84%) in the control condition. The group mean was 4.20% (SD = 5.48%) higher in the experimental condition than that in the control condition; this difference was statistically significant (t(14) = 2.97, p=0.010).

Production and perception of speech intonation in pediatric cochlear implant recipients and individuals with normal hearing.

OBJECTIVES: Current cochlear implant (CI) devices are limited in providing voice pitch information that is critical for listeners' recognition of prosodic contrasts of speech (e.g., intonation and lexical tones). As a result, mastery of the production and perception of such speech contrasts can be very challenging for prelingually deafened individuals who received a CI in their childhood (i.e., pediatric CI recipients). The purpose of this study was to investigate (a) pediatric CI recipients' mastery of the production and perception of speech intonation contrasts, in comparison with their age-matched peers with normal hearing (NH), and (b) the relationships between intonation production and perception in CI and NH individuals. DESIGN: Twenty-six pediatric CI recipients aged from 7.44 to 20.74 yrs and 17 age-matched individuals with NH participated. All CI users were prelingually deafened, and each of them received a CI between 1.48 and 6.34 yrs of age. Each participant performed an intonation production task and an intonation perception task. In the production task, 10 questions and 10 statements that were syntactically matched (e.g., "The girl is on the playground." versus "The girl is on the playground?") were elicited from each participant using interactive discourse involving pictures. These utterances were judged by a panel of eight adult listeners with NH in terms of utterance type accuracy (question versus statement) and contour appropriateness (on a five-point scale). In the perception task, each participant identified the speech intonation contrasts of natural utterances in a two-alternative forced-choice task. RESULTS: The results from the production task indicated that CI participants' scores for both utterance type accuracy and contour appropriateness were significantly lower than the scores of NH participants (both p < 0.001). The results from the perception task indicated that CI participants' identification accuracy was significantly lower than that of their NH peers (CI, 70.13% versus NH, 97.11%, p < 0.001). The Pearson correlation coefficients (r) between CI participants' performance levels in the production and perception tasks were approximately 0.65 (p = 0.001). CONCLUSION: As a group, pediatric CI recipients do not show mastery of speech intonation in their production or perception to the same extent as their NH peers. Pediatric CI recipients' performance levels in the production and perception of speech intonation contrasts are moderately correlated. Intersubject variability exists in pediatric CI recipients' mastery levels in the production and perception of speech intonation contrasts. These findings suggest the importance of addressing both aspects (production and perception) of speech intonation in the aural rehabilitation and speech intervention programs for prelingually deafened children and young adults who use a CI.

Complications in children with long-term cochlear implants.

OBJECTIVES: To evaluate the complications in children who underwent cochlear implantation between 1991 and 2002 at Chi Mei Medical Center, Taipei Medical University. METHOD: The medical records of 169 cases of pediatric cochlear implants from 1991 to 2002 with a follow-up period of 3-11 years were reviewed for demographics and complications. A follow-up phone call and clinical visits were performed to determine the long-term results. RESULTS: The medical-surgical complications were facial nerve stimulation, transient dizziness, flap breakdown, minor change of taste, cholesteatoma, otitis media with effusion and mastoiditis. The device-related complications included 4 device failures and 1 device breakage in a traffic accident. CONCLUSION: Chronic otitis media and cholesteatoma developed in children as long-term complications and surgical challenges. Nevertheless, cochlear implantation surgery in children is a reliable and safe procedure with a low percentage of severe complications. To prevent cholesteatoma formation, parents are advised to schedule a regular ENT consultation at least yearly for early identification and treatment in the stages of acute otitis media or drum retraction.

Prevalence of hearing impairment in a rural midwestern cohort: estimates from the Keokuk county rural health study, 1994 to 1998.

OBJECTIVE: The current paper estimates the prevalence of hearing problems in a rural population, analyzes the prevalence of hearing problems across age groups, and compares the prevalence of hearing problems in this population with results obtained in other populations. DESIGN: Data were obtained from a random sample of the residents of a rural county, stratified by farm, rural non-farm, and town residence. Hearing test results were obtained from participants between the ages of 8 and 92 years (N = 1972; 47% male). Pure-tone thresholds were classified as normal or impaired using a number of metrics, including speech intelligibility index values. Selected comparisons of crude rates were made with previous population-based studies of hearing loss prevalence. RESULTS: Nearly all (99%) of the participants in this study had significant hearing impairment. Atypical hearing impairment is most prevalent at 6 kHz. In males, this excess impairment shifts to lower frequencies with age but monotonically decreases in females. Notched configurations were most common among those between 30 and 59 years old. In females, the prevalence of hearing impairments sufficient to interfere with speech understanding begins to rapidly increase in the 6th decade (4th decade in males). Comparisons with prior population-based studies in the United States and Great Britain identified few significant differences. CONCLUSIONS: Significant hearing impairment is common in rural populations. The high prevalence in this population is similar to that found in other population-based studies. Future studies are needed to examine (1) the risk factors for hearing impairment, (2) the natural course of hearing problems across the life span, and (3) the effect of programs for the prevention of hearing impairment and rehabilitation for persons with existing hearing impairments.

Perception and production of mandarin tones in prelingually deaf children with cochlear implants.

OBJECTIVE: Mandarin is a lexical tone language in which four tones are crucial for determining lexical meanings. Acquisition of such a tone system may be challenging to prelingually deaf children with cochlear implants because, as recent studies have shown, cochlear implant devices are ineffective in encoding voice pitch information required for tone recognition. This study aimed to investigate Mandarin tone production and perception skills of children with cochlear implants. DESIGN: Thirty prelingually deaf children with cochlear implants, ages 6;0 (yr;mo) to 12;6, participated. These children received their implants at an average age of 5;8, with a range from 2;3 to 10;3. The average length of their cochlear implant experience was 3;7, with a range from 1;7 to 6;5. Tasks of tone production and tone identification involved a pictorial protocol of 48 words containing the targeted tones in either monosyllabic or disyllabic forms. RESULTS: The average scores for tone production was 53.09% (SD = 15.42), and for tone identification was 72.88% (SD = 19.68; chance level = 50%). Significant differences were found in the percentages across the production or identification of tone types or tone pairs. The children with exceptional performance in tone production tended to also perform well in tone identification. The children's performance levels in tone identification and production were also discussed in relation to the factors of age at implantation and length of cochlear implant experience. CONCLUSIONS: The present results suggest that the majority of prelingually deaf children with cochlear implants did not master Mandarin tone production. However, a small group of participants demonstrated nearly perfect skills of Mandarin tone production in addition to tone perception. Thus, it is necessary to consider factors other than the device's limitations to explain these high levels of performance in the perception and production of Mandarin lexical tones.