Consonant development in pediatric cochlear implant users who were implanted before 30 months of age

Speech production skills of bilingual children using cochlear implants

Evidence is lacking on the impact of bilingualism on the speech skills of children with cochlear implants (CIs). This study described the speech production of children with CIs acquiring French and one or more additional spoken languages. Four groups of children aged 4-11 were included: bilinguals (n = 15) and monolinguals (n = 14) with CIs and bilinguals (n = 14) and monolinguals (n = 20) with typical hearing. Data were collected about the percentage of consonant correct (PCC) and vowel correct (PVC) produced in French and intelligibility in all languages they spoke. Bilingual and monolingual children with CIs had comparable speech accuracy in French, but the pattern differed, impacting PCC for bilinguals and PVC for monolinguals. Most children with CIs had accurate and intelligible speech in French, but few bilingual children with CIs were highly intelligible in their home language. Therefore, bilingualism did not impede the speech production outcomes of bilingual children with CIs in the language of the wider community.

Factors affecting consonant production accuracy in children with cochlear implants: Expressive vocabulary and maternal education

BACKGROUND

Despite the ability of cochlear implants (CIs) to provide children with access to speech, there is considerable variability in spoken language outcomes. Research aimed at identifying factors influencing speech production accuracy is needed.

AIMS

To characterize the consonant production accuracy of children with cochlear implants (CWCI) and an age-matched group of children with typical hearing (CWTH) and to explore several factors that potentially affect the ability of both groups to accurately produce consonants.

METHODS & PROCEDURES

We administered the Bankson-Bernthal Test of Phonology (BBTOP) to a group of 25 CWCI (mean age = 4;9, SD = 1;6, range = 3;2-8;5) implanted prior to 30 months of age with a mean duration of implant usage of 3;6 and an age-matched group of 25 CWTH (mean age = 5;0, SD = 1;6, range = 3;1-8;6). The recorded results were transcribed, and the accuracy of the target consonants was determined. Expressive vocabulary size estimates were obtained from a language sample using the number of different words (NDW). A parent questionnaire provided information about maternal education, duration of CIs experience and other demographic characteristics of each child.

OUTCOMES & RESULTS

The CWCI group demonstrated some similarities to, and some differences from, their hearing peers. The CWCI demonstrated poorer consonant production accuracy overall and in various phonetic categories and word positions. However, both groups produced initial consonants more accurately than final consonants. Whilst CWCI had poorer production accuracy than CWTH for all phonetic categories (stops, nasals, fricatives, affricates, liquids and glides and consonant clusters), both groups exhibited similar error patterns across categories. For CWCI, the factors most related to consonant production accuracy when considered individually were expressive vocabulary size, followed by duration of CI experience, chronological age, maternal education and gender. The combination of maternal education and vocabulary size resulted in the best model of consonant production accuracy for this group. For the CWTH, chronological age followed by vocabulary size were most related to consonant production accuracy. No combination of factors yielded an improved model for the CWTH.

CONCLUSIONS & IMPLICATIONS

Whilst group differences in production accuracy between the CWCI and CWTH were found, the pattern of errors was similar for the two groups of children, suggesting that the children are at earlier stages of overall consonant production development. Although duration of CI experience was a significant covariate in a single-variable model of consonant production accuracy for CWCI, the best multivariate model of consonant production accuracy for these children was based on the combination of expressive vocabulary size and maternal education.

WHAT THIS PAPER ADDS

What is already known on the subject Research has shown that a range of factors is associated with consonant production accuracy by CWCIs, including factors such as the age at implant, duration of implant use, gender, other language skills and maternal education. Despite numerous studies that have examined speech sound production in these children, most have explored a limited number of factors that might explain the variability in scores obtained. Research that examines the potential role of a range of child-related and environmental factors in the same children is needed to determine the predictive role of these factors in speech production outcomes. What this paper adds to the existing knowledge Whilst the consonant production accuracy was lower for the CWCIs than for their typically hearing peers, there were some similarities suggesting that these children are experiencing similar, but delayed, acquisition of consonant production skills to that of their hearing peers. Whilst several factors are predictive of consonant production accuracy in children with implants, vocabulary diversity and maternal education, an indirect measure of socio-economic status, were the best combined predictors of consonant production accuracy. What are the potential or actual clinical implications of this work? Understanding the factors that shape individual differences in CWCI speech production is important for effective clinical decision-making and intervention planning. The present findings point to two potentially important factors related to speech sound production beyond the duration of robust hearing in CWCI, namely, a lexical diversity and maternal education. This suggests that intervention is likely most efficient that addresses both vocabulary development and speech sound development together. The current findings further suggest the importance of parental involvement and commitment to spoken language development and the importance of receiving early and consistent intervention aimed both at skill development and parental efficacy.

Covert contrasts and categorical perception: a comparison of two measurement tools

This study considers adults' perception of subtle differences in the error productions of /r/ and /l/ in young children. Given that these two phonemes share a common substitution [w], the potential covert contrast between these three sounds was investigated. The utility of two perceptual rating scales was compared: a linear visual analogue scale (VAS) and a triangular scale that considered the possibility of covert contrast among /r,l,w/. Adult listeners rated speech productions from children with cochlear implants (CIs) and speech age-matched children with normal hearing (NH) as they produced VCV or CV productions with /r,l,w/ in syllable-initial position. Mahalanobis distances of the listener ratings for each stimulus on each rating scale were calculated for analysis. Ultimately, there was no difference between the ratings of the two speaker populations. However, there was a significant difference in the amount of variability captured with each scale. The triangular scale reliably captured more variability in the productions than the linear VAS. The significant effect of scale type on the spread of listeners' responses provides support for the claim that the type of rating system used can capture different aspects of a listener's perceptions, thereby suggesting that the type of rating system used in a study may significantly influence that study's findings.

Efficacy of cochlear implants in children with borderline hearing who have already achieved significant language development with hearing aids

There are still debates about timing and effectiveness of cochlear implants (CI) in pediatric subjects with significant residual hearing who do not belong to traditional indication of CI. In this study, we aimed to investigate the outcomes of CI, specifically on improvement of pronunciation, among hearing-impaired children already with a substantial degree of language skills as evaluated by Categories of Auditory Perception (CAP) scores or sentence score. Our cohort comprised pediatric CI recipients from July 2018 through October 2020. Among them, cases with CAP scores of 5 or 6 preoperatively were defined as "borderline cases". We investigated prevalence and etiologies, and compared speech evaluation data preoperatively and postoperatively at three time points (3, 6 and 9-12 months after implantation). Among 86 pediatric CI recipients, 13 subjects (15.12%) had language development that reached CAP scores of 5 or 6 before implantation. Postoperative speech evaluation data 6 months after implantation revealed significant improvement of pronunciation (Urimal Test of Articulation and Phonation scores: UTAP), Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) and word perception scores, but not of CAP and sentence perception scores. Notably, the significant improvement of pronunciation based on UTAP scores outstripped that of other speech parameters and this continued steadily up to one-year postoperatively. The result of the study serves as evidence for what to expect from cochlear implantation in hearing-impaired children who have already achieved a substantial degree of language development in terms of CAP scores or sentence perception scores, preoperatively.

Effects of Device Limitations on Acquisition of the /t/-/k/ Contrast in Children With Cochlear Implants

OBJECTIVES

The present study investigated how development of the /t/-/k/ contrast is affected by the unique perceptual constraints imposed on young children using cochlear implants (CIs). We hypothesized that children with CIs would demonstrate unique patterns of speech acquisition due to device limitations, rather than straightforward delays due to a lack of auditory input in the first year of life before implantation. This study focused on the contrast between /t/ and /k/ because it is acquired early in the sequence of development, requires less advanced motor control than later-acquired place contrasts, is differentiated by spectral cues (which are particularly degraded when processed by CIs), and is not easily differentiated by visual cues alone. Furthermore, perceptual confusability between /t/ and /k/ may be exacerbated in front-vowel contexts, where the spectral energy for /k/ is shifted to higher frequencies, creating more spectral overlap with /t/.

DESIGN

Children with CIs (n = 26; ages 31 to 66 mo) who received implants around their first birthdays were matched to peers with normal hearing (NH). Children participated in a picture-prompted auditory word-repetition task that included over 30 tokens of word-initial /t/ and /k/ consonants. Tokens were balanced across front-vowel and back-vowel contexts to assess the effects of coarticulation. Productions were transcribed and coded for accuracy as well as the types of errors produced (manner of articulation, voicing, or place of articulation errors). Centroid frequency was also calculated for /t/ and /k/ tokens that were produced correctly. Mixed-effects models were used to compare accuracy, types of errors, and centroid frequencies across groups, target consonants, and vowel contexts.

RESULTS

Children with CIs produced /t/ and /k/ less accurately than their peers in both front- and back-vowel contexts. Children with CIs produced /t/ and /k/ with equal accuracy, and /k/ was produced less accurately in front-vowel contexts than in back-vowel contexts. When they produced errors, children with CIs were more likely to produce manner errors and less likely to produce voicing errors than children with NH. Centroid frequencies for /t/ and /k/ were similar across groups, except for /k/ in front-vowel contexts: children with NH produced /k/ in front-vowel contexts with higher centroid frequency than children with CIs, and they produced /k/ and /t/ with equal centroid frequencies in front-vowel contexts.

CONCLUSIONS

Children with CIs not only produced /t/ and /k/ less accurately than peers with NH, they also demonstrated idiosyncratic patterns of acquisition, likely resulting from receiving degraded and distorted spectral information critical for differentiating /t/ and /k/. Speech-language pathologists should consider perceptual confusability of consonants (and their allophonic variations) during their assessment and treatment of this unique population of children.

Prelinguistic Consonant Production and the Influence of Mouthing Before and After Cochlear Implantation

OBJECTIVES

The goal of the study was to investigate prelinguistic consonant production and the influence of vocalizations that co-occurred with object mouthing on consonant production in infants with profound sensorineural hearing loss before and after cochlear implantation to advance knowledge of early speech development in infants with profound hearing loss.

DESIGN

Participants were 43 infants, 16 infants with profound sensorineural hearing loss and 27 hearing infants. In the mixed longitudinal and cross-sectional design, infants with profound hearing loss and age-matched hearing infants participated before cochlear implantation, at an average age of 9.9 mo, and/or after cochlear implantation, at an average age of 17.8 mo. Mean age at cochlear implantation for infants with profound hearing loss was 12.4 mo; mean duration of cochlear implant use at time of testing was 4.2 mo.

RESULTS

Before and after cochlear implantation, infants with profound hearing loss produced significantly fewer supraglottal consonants per consonant-vowel vocalization than hearing peers and had smaller overall consonant inventories. Before, but not after cochlear implantation, infants with profound hearing loss produced proportionally more vocalizations, supraglottal consonant-vowel vocalizations, and different supraglottal consonants in vocalizations during mouthing than did hearing infants.

CONCLUSIONS

The results document consonant production before cochlear implantation in a larger group of infants with profound hearing loss than previously examined. The results also extend evidence of early delays in consonant production to infants who received cochlear implants at 12 mo of age, and show that they likely miss the potential benefits of auditory-motor feedback in vocalization-mouthing combinations that occur before they have access to sound through cochlear implants.

Consonant and vowel production in the spontaneous speech productions of children with auditory brainstem implants

Auditory brainstem implantation provides hearing sensations in children and adults with anomalies of the auditory nerves. In children, perceptual benefits have been established, and research already demonstrated (limited) effects on children's speech production. The current study extends the literature by scrutinizing the phonological development of three children with ABI. Spontaneous speech samples were used to establish their phonemic inventories of vowels, word-initial consonants and word-final consonants, both independently of the target phoneme and relative to the target phoneme. The three children produced all vowels with longer device use and larger vocabulary size. Word-initial and word-final consonants appeared in the three children's spontaneous productions. However, the segmental accuracy was only moderate in the children's productions.

Assessing consonant production in children with cochlear implants

OBJECTIVE

The objective of this study was to investigate the development of consonant inventory and accuracy in pediatric cochlear implant (CI) recipients and compare their performance to typical hearing (TH) children.

METHODS

One hundred and twenty nine children with CIs, implanted between 6-38 months of age, and 30 age-matched children with TH participated in this study. Spontaneous speech samples were collected at 3.5 and 4.5 years chronological age and the first 100 different words spoken by each participant were transcribed. Two consonant production measures were subsequently calculated to assess consonant acquisition and mastery. The percentage of Consonants Correct (CC) was used for measuring accuracy and Consonant Diversity (CD), an inventory measure, was used to identify the number of different consonants spoken by each participant. Repeated measures analyses of variance were conducted to examine the differences in consonant production scores based on presence of CI (participants with CI versus typical hearing (TH) participants), and chronological age at data collection (3.5 years versus 4.5 years).

RESULTS

CI recipients displayed lower consonant production scores compared to TH children. Children with the most device experience (32-38 months at 3.5 years) performed on par with their TH peers.

CONCLUSIONS

The two measures used in this study together appear capable of comprehensively describing the changes in consonant production skills of children. Results from this study indicate that while most CI participants display lower scores compared to TH children, many of the CI users are able to produce speech sounds on par with TH children.

Profound Hearing Loss: Addressing Barriers to Hearing Healthcare

The impact of profound hearing loss on infants and adults is variable and greatly influenced by improved audition derived from hearing aids and cochlear implants. However, barriers to healthcare, hearing healthcare in particular, can offset the benefits provided by these sensory devices. Common barriers include cost, location, availability of trained professionals, acceptance of the hearing loss, language and cultural differences, secondary disabilities, and mental health issues. These barriers and their distinct presentations vary somewhat by age, language, and where people live (urban vs. rural), and can interfere with receiving testing and devices in a timely manner. They also can limit auditory, speech and language therapies, and interfere with acceptance of the hearing loss and devices. Rehabilitation should focus on eliminating or reducing the adverse impact of these barriers on patients and their families. Some of which can be done through professional training and multidisciplinary activities, counseling, and community outreach.

Consonant Acquisition in Young Cochlear Implant Recipients and Their Typically Developing Peers

PURPOSE

Consonant acquisition was examined in 13 young cochlear implant (CI) recipients and 11 typically developing (TD) children.

METHOD

A longitudinal research design was implemented to determine the rate and nature of consonant acquisition during the first 2 years of robust hearing experience. Twenty-minute adult-child (typically a parent) interactions were video and audio recorded at 3-month intervals following implantation until 24 months of robust hearing experience was achieved. TD children were similarly recorded between 6 and 24 months of age. Consonants that were produced twice within a 50-utterance sample were considered "established" within a child's consonant inventory.

RESULTS

Although the groups showed similar trajectories, the CI group produced larger consonant inventories than the TD group at each interval except for 21 and 24 months. A majority of children with CIs also showed more rapid acquisition of consonants and more diverse consonant inventories than TD children.

CONCLUSIONS

These results suggest that early auditory deprivation does not significantly affect consonant acquisition for most CI recipients. Tracking early consonant development appears to be a useful way to assess the effectiveness of cochlear implantation in young recipients.

Word initial fricative production in children with cochlear implants and their normally hearing peers matched on lexicon size

Fricative production is affected in children with cochlear implants (CI) as compared to age-matched normally hearing (NH) children. However, the phonological development of children with CI is rarely compared to that of NH peers matched on lexicon size. We compare the early word initial fricative development of 10 children with CI and 30 NH children matched on lexicon size and on chronological age. Children with CI are expected to differ from their NH peers when they are matched on chronological age. But, are lexical development and phonological development commensurate in children with CI as they have been shown to be in NH children? Results show that fricative production in children with CI deviates from that of age-matched NH peers. The differences between both groups disappear when they were matched on lexicon size. Thus, phonological development in children with CI is similar to that of their NH peers with comparable lexicon sizes.

Current trends in outcome studies for children with hearing loss and the need to establish a comprehensive framework of measuring outcomes in children with hearing loss in China

Since the 1970s, outcome studies for children with hearing loss expanded from focusing on assessing auditory awareness and speech perception skills to evaluating language and speech development. Since the early 2000s, the multi-center large scale research systematically studied outcomes in the areas of auditory awareness, speech-perception, language development, speech development, educational achievements, cognitive development, and psychosocial development. These studies advocated the establishment of baseline and regular follow-up evaluations with a comprehensive framework centered on language development. Recent research interests also include understanding the vast differences in outcomes for children with hearing loss, understanding the relationships between neurocognitive development and language acquisition in children with hearing loss, and using outcome studies to guide evidence-based clinical practice. After the establishment of standardized Mandarin language assessments, outcomes research in Mainland China has the potential to expand beyond auditory awareness and speech perception studies.

Spoken english language development among native signing children with cochlear implants

Bilingualism is common throughout the world, and bilingual children regularly develop into fluently bilingual adults. In contrast, children with cochlear implants (CIs) are frequently encouraged to focus on a spoken language to the exclusion of sign language. Here, we investigate the spoken English language skills of 5 children with CIs who also have deaf signing parents, and so receive exposure to a full natural sign language (American Sign Language, ASL) from birth, in addition to spoken English after implantation. We compare their language skills with hearing ASL/English bilingual children of deaf parents. Our results show comparable English scores for the CI and hearing groups on a variety of standardized language measures, exceeding previously reported scores for children with CIs with the same age of implantation and years of CI use. We conclude that natural sign language input does no harm and may mitigate negative effects of early auditory deprivation for spoken language development.