Yongxin Li

Tone Production in Mandarin-speaking Children with Cochlear Implants: A Preliminary Study

Objective More than a quarter of the worlds population speak tone languages, such as Mandarin Chinese. In those languages, the pitch or tone pattern of a monosyllabic word conveys lexical meaning. The purpose of this study was to investigate tone production in Mandarin-speaking children with cochlear implants (CIs). Material and Methods Speech samples were recorded from seven normal-hearing and four CI children aged 4–9 years. All subjects were native Mandarin speakers. The speech samples were used for acoustic analysis of the tone patterns, i.e. the fundamental frequency contours. In addition, a tone intelligibility test was carried out in which four normal-hearing native Mandarin-speaking adults listened to the speech materials and judged the intelligibility of the childrens tone production. Results The tone production for the seven normal-hearing children was considered to be perfect in the intelligibility test. Acoustic analysis of the speech materials of the normal-hearing children produced the four typical tone patterns of Mandarin Chinese: (i) high and flat; (ii) rising; (iii) low and dipping; and (iv) falling. The tone patterns produced by the children with CIs tended to be flat, with some other patterns being irregular. The results of the tone intelligibility tests also showed degraded intelligibility of tone patterns. Conclusion A potential speech development deficit was documented in prelingually deafened children with CIs whose native language is a tone language. The imperfect tone production of the implant children, which can be attributed to the paucity of pitch information delivered via the current CI stimulation, may have significant implications for communication using tone languages. Further research is warranted to determine factors that may affect tone development in children with CIs.

Tone perception and production in pediatric cochlear implants users

Abstract Conclusions: In prelingually deaf children with cochlear implants, tone perception and production performance are highly correlated. This result is consistent with the hypothesis that tone perception is the prerequisite for good tone production. Objectives: Previous research has shown remarkable deficits in tone perception and production in native tone language-speaking, prelingually deafened children with cochlear implants. The purpose of the present study was to investigate the relationship between tone perception and production in those children. Methods: Twenty-five prelingually deaf children with cochlear implants participated in the study. All subjects were Advanced Bionics CII/90K users with various lengths of implant use. To evaluate tone perception performance, subjects completed a computerized tone contrast test. For tone production performance, an artificial neural network was used to evaluate the accuracy of tones recorded from each of the 25 subjects. Results: Large individual differences in tone perception and production performance were observed in these subjects. Tone perception accuracy ranged from 50.0 to 96.9% correct (chance performance = 50% correct; mean = 71.0% correct). Tone production performance ranged from 19.4 to 97.2% correct (mean = 52.0% correct). A strong correlation was found between tone perception and production performance in this group of subjects (r = 0.805).

Vocal singing by prelingually-deafened children with cochlear implants

The coarse pitch information in cochlear implants might hinder the development of singing in prelingually-deafened pediatric users. In the present study, seven prelingually-deafened children with cochlear implants (5.4-12.3 years old) sang one song that was the most familiar to him or her. The control group consisted of 14 normal-hearing children (4.1-8.0 years old). The fundamental frequencies (F0) of each note in the recorded songs were extracted. The following five metrics were computed based on the reference music scores: (1) F0 contour direction of the adjacent notes, (2) F0 compression ratio of the entire song, (3) mean deviation of the normalized F0 across the notes, (4) mean deviation of the pitch intervals, and (5) standard deviation of the note duration differences. Children with cochlear implants showed significantly poorer performance in the pitch-based assessments than the normal-hearing children. No significant differences were seen between the two groups in the rhythm-based measure. Prelingually-deafened children with cochlear implants have significant deficits in singing due to their inability to manipulate pitch in the correct directions and to produce accurate pitch height. Future studies with a large sample size are warranted in order to account for the large variability in singing performance.

Comparisons between Neural Response Imaging thresholds, electrically evoked auditory reflex thresholds and most comfortable loudness levels in CII Bionic Ear users with HiResolution™ sound processing strategies

Conclusions. The data collected in this study indicated that first Neural Response Imaging (NRI) thresholds had a better correlation with HiResolution™ most comfortable loudness (M) levels than tNRI thresholds. Electrically evoked auditory reflex thresholds (EARTs) had a higher correlation with HiResolution M levels than tNRI thresholds and a lower correlation than first NRI thresholds. NRI is a very useful method for programming the cochlear implants of young children who cannot demonstrate a reliable judgment of loudness. Objective. To investigate how HiResolution sound processing, designed to deliver high-rate stimuli, relates to EARTs and electrically evoked compound action potential measurements produced by low-rate stimuli. Material and methods. Nine profoundly hearing-impaired children and adults aged 6–29 years participated in the study. NRI responses were elicited using pulse trains consisting of biphasic pulses at a pulse width per phase of 32 µs delivered at a frequency of 30 Hz using SoundWave programming software. Stimuli were delivered to the odd electrodes (1, 3, 5, 7, 9, 11, 13 and 15) along the array. tNRI (NRI threshold) and first NRI thresholds were recorded for each stimulating electrode. “Speech bursts” stimuli used in EARTs recording were delivered to four electrodes at a time and stapedial reflexes were recorded from the impedance bridge. The M levels used were those used by each patient in their everyday HiResolution programs. Results. For 8 patients (53 stimulating electrodes) the correlation between tNRI threshold and M level was ru200a=u200a0.675 (pu200a=u200a0.000) and that between first NRI thresholds and M level was r=0.741 (pu200a=u200a0.000). On average the M-level value was 20 CU (Current Unit) lower than the first NRI threshold value and 12 CU higher than the tNRI threshold value. The M-level patterns across the electrode array overall were similar to the tNRI or first NRI threshold patterns. For 7 patients (112 stimulating electrodes) the correlation between EART and M levels was r=0.710 (pu200a=u200a0.000). On average the EART value was 14 CU higher than the M-level value.

Recognition of lexical tone production of children with an artificial neural network

Conclusion. This study demonstrated that the artificial neural network can successfully classify Mandarin Chinese tone patterns produced by multiple children. The neural network can be used as an objective way of evaluating tone production of children. Objectives. Traditionally, tone production is evaluated subjectively using human listeners. The aim of the present study was to investigate the efficacy of using an artificial neural network in evaluating tone production of Mandarin-speaking children. Subjects and methods. Speech materials were recorded from 61 normal-hearing children. The fundamental frequency (F0) of each monosyllabic word was extracted and then used as inputs to a feed-forward backpropagation artificial neural network. The number of inputs was set at 12, whereas the number of hidden neurons was set at 16 in the neural network. The output layer consisted of four neurons representing the four Mandarin tone patterns. The tone recognition performance of the neural network was further compared with that of native Mandarin-speaking adult listeners. Results. The neural network successfully classified the tone patterns of the 61 child speakers with an accuracy of about 85% correct. This high accuracy exceeded the tone recognition performance by the adult listeners. Individual child speakers showed varied tone production accuracy as recognized by the adult listeners or by the neural network.

Speech development in young children with Mondini dysplasia who had undergone cochlear implantation

OBJECTIVEnThe purpose of this study was to investigate the development of speech skills in young children with Mondini dysplasia and age-matched deaf children with radiologically normal inner ears over a period of 5 years after cochlear implantation (CI).nnnMETHODSnIn total, 700 congenitally severely to profoundly deaf children (281 girls and 419 boys) participated in this study. All of the participants had undergone unilateral CI surgery before 36 months of age. The participants were categorized into two groups based on the absence or presence of Mondini dysplasia in the implanted ear, as assessed via high-resolution, thin-slice computerized tomography or magnetic resonance imaging: group A comprised 592 children with radiologically normal inner ears and group B comprised 108 children with Mondini dysplasia. The Meaningful Use of Speech Scale (MUSS) and Speech Intelligibility Rating (SIR) were used to evaluate the speech performance of all young children at various time points: pre-surgery and at 1, 3, 6, 12, 24, 36, 48, and 60 months after switch-on programming.nnnRESULTSnThe mean scores of SIR and MUSS in children from both group A and group B showed significant improvements over time. No significant differences were found in the mean scores of SIR between the two groups at any time interval during the 5-year follow-up. The mean score of MUSS was significantly different between group A and group B at 12, 24, and 36 months after implantation, whereas no obvious differences were noted pre-surgery, and at 1, 3, 6, 48, and 60 months post-operation.nnnCONCLUSIONSnYoung children with Mondini dysplasia develop their speech skills at a fast rate and achieve similar speech acquisition compared to age-matched children with radiologically normal inner ears 5 years post-operation. Therefore, CI is an effective intervention method for young children with Mondini dysplasia.