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.

The Lombard effect observed in speech produced by cochlear implant users in noisy environments: A naturalistic study.

The Lombard effect is an involuntary response speakers experience in the presence of noise during voice communication. This phenomenon is known to cause changes in speech production such as an increase in intensity, pitch structure, formant characteristics, etc., for enhanced audibility in noisy environments. Although well studied for normal hearing listeners, the Lombard effect has received little, if any, attention in the field of cochlear implants (CIs). The objective of this study is to analyze speech production of CI users who are postlingually deafened adults with respect to environmental context. A total of six adult CI users were recruited to produce spontaneous speech in various realistic environments. Acoustic-phonetic analysis was then carried out to characterize their speech production in these environments. The Lombard effect was observed in the speech production of all CI users who participated in this study in adverse listening environments. The results indicate that both suprasegmental (e.g., F0, glottal spectral tilt and vocal intensity) and segmental (e.g., F1 for /i/ and /u/) features were altered in such environments. The analysis from this study suggests that modification of speech production of CI users under the Lombard effect may contribute to some degree an intelligible communication in adverse noisy environments.

Prior exposure to a reverberant listening environment improves speech intelligibility in adult cochlear implant listeners.

OBJECTIVES: The goal of this study is to investigate whether prior exposure to reverberant listening environment improves speech intelligibility of adult cochlear implant (CI) users. METHODS: Six adult CI users participated in this study. Speech intelligibility was measured in five different simulated reverberant listening environments with two different speech corpuses. Within each listening environment, prior exposure was varied by either having the same environment across all trials (blocked presentation) or having different environment from trial to trial (unblocked). RESULTS: Speech intelligibility decreased as reverberation time increased. Although substantial individual variability was observed, all CI listeners showed an increase in the blocked presentation condition as compared to the unblocked presentation condition for both speech corpuses. CONCLUSION: Prior listening exposure to a reverberant listening environment improves speech intelligibility in adult CI listeners. Further research is required to understand the underlying mechanism of adaptation to listening environment.

Persistent Language Delay Versus Late Language Emergence in Children With Early Cochlear Implantation.

PURPOSE: The purpose of the present investigation is to differentiate children using cochlear implants (CIs) who did or did not achieve age-appropriate language scores by midelementary grades and to identify risk factors for persistent language delay following early cochlear implantation. MATERIALS AND METHOD: Children receiving unilateral CIs at young ages (12-38 months) were tested longitudinally and classified with normal language emergence (n = 19), late language emergence (n = 22), or persistent language delay (n = 19) on the basis of their test scores at 4.5 and 10.5 years of age. Relative effects of demographic, audiological, linguistic, and academic characteristics on language emergence were determined. RESULTS: Age at CI was associated with normal language emergence but did not differentiate late emergence from persistent delay. Children with persistent delay were more likely to use left-ear implants and older speech processor technology. They experienced higher aided thresholds and lower speech perception scores. Persistent delay was foreshadowed by low morphosyntactic and phonological diversity in preschool. Logistic regression analysis predicted normal language emergence with 84% accuracy and persistent language delay with 74% accuracy. CONCLUSION: CI characteristics had a strong effect on persistent versus resolving language delay, suggesting that right-ear (or bilateral) devices, technology upgrades, and improved audibility may positively influence long-term language outcomes.

Evaluation and analysis of whispered speech for cochlear implant users: Gender identification and intelligibility.

This study investigates the degree to which whispered speech impacts speech perception and gender identification in cochlear implant (CI) users. Listening experiments with six CI subjects under neutral and whispered speech conditions using sentences from the UT-Vocal Effort II corpus (recordings from male and female speakers) were conducted. Results indicated a significant effect of whispering on gender identification and speech intelligibility scores. In addition, no significant effect of talker gender on the speech/gender identification scores was observed. Results also suggested that exposure to longer speech stimuli, and consequently more temporal cues, would not improve gender identification performance in CI subjects.

Self-esteem in children and adolescents with hearing loss.

Children with hearing loss are at risk for lower self-esteem due to differences from hearing peers relative to communication skills, physical appearance, and social maturity. This study examines the influence of generic factors unrelated to hearing loss (e.g., age, gender, temperament) and specific factors associated with hearing loss (e.g., age at identification, communication skills) on how children with hearing loss wearing cochlear implants or hearing aids appraise self-esteem. Fifty children with hearing loss wearing cochlear implants or hearing aids participated (Mean age: 12.88 years; mean duration of device use: 3.43 years). Participants independently completed online questionnaires to assess communication skills, social engagement, self-esteem, and temperament. Children with hearing loss rated global self-esteem significantly more positively than hearing peers, t = 2.38, p = .02. Self-esteem ratings attained significant positive correlations with affiliation (r = .42, p = .002) and attention (r = .45, p = .001) temperaments and a significant negative association with depressive mood (r = - .60, p < .0001). No significant correlations emerged between self-esteem and demographic factors, communication skills, or social engagement. Because successful communication abilities do not always co-occur with excellent quality of life, clinicians and professionals working with children with hearing loss need to understand components contributing to self-esteem to improve identification, counseling, and external referrals for children in this population.

American parent perspectives on quality of life in pediatric cochlear implant recipients.

OBJECTIVES: Cochlear implantation influences not only communication but also psychosocial outcomes in children with severe to profound hearing loss. Focusing on issues specific to cochlear implantation (e.g., self-reliance, social relations, education, effects of implantation, and supporting the child) may provide a more accurate and relative view of functional status of pediatric cochlear implant (CI) recipients. The present study analyzes parental perspectives of CI-specific health-related quality of life (HRQoL) in children with CIs to determine (a) if parents differentially rate their child's quality of life according to psychosocial domain (e.g., communication, self-reliance, education); (b) if associations exist between quality of life domains specific to cochlear implantation in pediatric implant recipients; and (c) if demographic variables (i.e., chronologic age, age at cochlear implantation, duration of device experience) mediate parent ratings of quality of life in pediatric CI recipients. DESIGN: Parents of 33 children with CIs (mean age, 9.85 years; mean age of CI activation, 2.47 years; mean device experience, 7.47 years) completed a validated condition-specific questionnaire, Children With Cochlear Implants: Parental Perspectives. RESULTS: Parents positively rated most HRQoL domains, although education and effects of implantation received significantly less positive ratings (p < 0.01). Three domains (communication, self-reliance, and well-being) significantly correlated with at least 5 other domains, suggesting that positivity in one domain co-occurs with positivity in other domains. Demographic variables (chronologic age, CI activation age, and duration of CI use) did not correlate significantly with psychosocial outcomes; rather, parents reported positive HRQoL and successful functional use of CI across demographic variables. CONCLUSIONS: Parents of children and adolescents with CIs rate overall HRQoL positively across psychosocial domains. Significantly less positive ratings of education and effects of implantation may result from limited access to CI-related accommodations and varying parent expectations, warranting further exploration to maximize psychosocial and performance outcomes in pediatric CI users.

Evaluation of adaptive dynamic range optimization in adverse listening conditions for cochlear implants.

The aim of this study is to investigate the effect of Adaptive Dynamic Range Optimization (ADRO) on speech identification for cochlear implant (CI) users in adverse listening conditions. In this study, anechoic quiet, noisy, reverberant, noisy reverberant, and reverberant noisy conditions are evaluated. Two scenarios are considered when modeling the combined effects of reverberation and noise: (a) noise is added to the reverberant speech, and (b) noisy speech is reverberated. CI users were tested in different listening environments using IEEE sentences presented at 65 dB sound pressure level. No significant effect of ADRO processing on speech intelligibility was observed.

Assessment of health-related quality of life 6 years after childhood cochlear implantation.

PURPOSE: To examine the impact of cochlear implant (CI) intervention on health-related quality of life (HRQOL) assessed by both self- and parent-reported measures. METHODS: In this national study of children implanted between ages 6 months and 5 years, HRQOL of 129 children 6-year post-CI was compared to 62 internal study (NH1) and 185 external (NH2) samples of hearing children frequency-matched to the CI group on sociodemographic variables. HRQOL ratings of children and their parents in each group, measured using the Child Health and Illness Profile-Child Edition, were compared, and their associations with the Family Stress Scale were investigated. RESULTS: CI children reported overall and domain-specific HRQOL that was comparable to both NH1 and NH2 peers. CI parents reported worse child scores than NH1 parents in Achievement, Resilience, and Global score (p's < 0.01) but similar or better scores than socioeconomically comparable NH2 parents. Higher family stress was negatively associated with all parent-reported HRQOL outcomes (p's < 0.01). Parent-child correlations in HRQOL global scores trended higher in CI recipients (r = 0.50) than NH1 (r = 0.42) and NH2 (r = 0.35) controls. CONCLUSIONS: CI recipients report HRQOL comparable to NH peers. These results, from both child and parent perspective, lend support to the effectiveness of CI intervention in mitigating the impact of early childhood deafness. Family stress was associated with worse HRQOL, underscoring a potential therapeutic target. Parent-child agreement in HRQOL scores was higher for CI families than NH families, which may reflect higher caregiver insight and involvement related to the CI intervention.

Emergence of speech sounds between 7 and 24 months of cochlear implant use.

OBJECTIVES: To investigate the process of speech development in five 42-month-old children with profound deafness who received cochlear implants (CIs) between 19 and 36 months of age and five normal hearing (NH) age mates. METHODS: Conversational samples were collected and transcribed. Sounds produced correctly within meaningful words (target sounds) and recognizable sounds produced in spontaneous productions (target-less sounds) were analyzed for all 10 children. RESULTS: Revealed that there was overlap in the total number of vowels and consonants produced by the two groups. The differences between the two groups were more evident in the target condition, whereas the two groups were more similar in the target-less condition. DISCUSSION: The similarities documented in the target-less repertoire of CI and NH children underscore the importance of examining the emerging sound system to predict the end-point sound system in children with CIs. Using target and target-less speech sound comparisons offers a supplementary view of the emergent process of speech sound development and is a valid method of analysis. Results suggest that early implantation may help some children with profound deafness develop speech sounds in a manner similar to NH age mates.

A tribute to a remarkably sound solution.

For their work on the development of the modern cochlear implant, which bestows hearing to individuals with profound deafness, Ingeborg Hochmair, Graeme Clark, and Blake Wilson are the 2013 recipients of the Lasker∼DeBakey Clinical Medical Research Award.

Age-dependent cost-utility of pediatric cochlear implantation.

OBJECTIVES: Cochlear implantation (CI) has become the mainstay of treatment for children with severe-to-profound sensorineural hearing loss (SNHL). Yet, despite mounting evidence of the clinical benefits of early implantation, little data are available on the long-term societal benefits and comparative effectiveness of this procedure across various ages of implantation-a choice parameter for parents and clinicians with high prognostic value for clinical outcome. As such, the aim of the present study is to evaluate a model of the consequences of the timing of this intervention from a societal economic perspective. Average cost utility of pediatric CI by age at intervention will be analyzed. DESIGN: Prospective, longitudinal assessment of health utility and educational placement outcomes in 175 children recruited from six U.S. centers between November 2002 and December 2004, who had severe-to-profound SNHL onset within 1 year of age, underwent CI before 5 years of age, and had up to 6 years of postimplant follow-up that ended in November 2008 to December 2011. Costs of care were collected retrospectively and stratified by preoperative, operative, and postoperative expenditures. Incremental costs and benefits of implantation were compared among the three age groups and relative to a nonimplantation baseline. RESULTS: Children implanted at <18 months of age gained an average of 10.7 quality-adjusted life years (QALYs) over their projected lifetime as compared with 9.0 and 8.4 QALYs for those implanted between 18 and 36 months and at >36 months of age, respectively. Medical and surgical complication rates were not significantly different among the three age groups. In addition, mean lifetime costs of implantation were similar among the three groups, at approximately $2000/child/year (77.5-year life expectancy), yielding costs of $14,996, $17,849, and $19,173 per QALY for the youngest, middle, and oldest implant age groups, respectively. Full mainstream classroom integration rate was significantly higher in the youngest group at 81% as compared with 57 and 63% for the middle and oldest groups, respectively (p < 0.05) after 6 years of follow-up. After incorporating lifetime educational cost savings, CI led to net societal savings of $31,252, $10,217, and $6,680 for the youngest, middle, and oldest groups at CI, respectively, over the child's projected lifetime. CONCLUSIONS: Even without considering improvements in lifetime earnings, the overall cost-utility results indicate highly favorable ratios. Early (<18 months) intervention with CI was associated with greater and longer quality-of-life improvements, similar direct costs of implantation, and economically valuable improved classroom placement, without a greater incidence of medical and surgical complications when compared to CI at older ages.

Influence of implantation age on school-age language performance in pediatric cochlear implant users.

OBJECTIVE: This study examined specific spoken language abilities of 160 children with severe-to-profound sensorineural hearing loss followed prospectively 4, 5, or 6 years after cochlear implantation. STUDY SAMPLE: Ninety-eight children received implants before 2.5 years, and 62 children received implants between 2.5 and 5 years of age. DESIGN: Language was assessed using four subtests of the Comprehensive Assessment of Spoken Language (CASL). Standard scores were evaluated by contrasting age of implantation and follow-up test time. RESULTS: Children implanted under 2.5 years of age achieved higher standard scores than children with older ages of implantation for expressive vocabulary, expressive syntax, and pragmatic judgments. However, in both groups, some children performed more than two standard deviations below the standardization group mean, while some scored at or well above the mean. CONCLUSIONS: Younger ages of implantation are associated with higher levels of performance, while later ages of implantation are associated with higher probabilities of continued language delays, particularly within subdomains of grammar and pragmatics. Longitudinal data from this cohort study demonstrate that after 6 years of implant experience, there is large variability in language outcomes associated with modifiers of rates of language learning that differ as children with implants age.

A comparative study of psychosocial development in children who receive cochlear implants.

OBJECTIVES: This study assessed self-reported quality of life of children with a cochlear implant (CI), comparing results with two published reports from the past decade. METHODS: Participants included 33 pediatric CI recipients with a mean age of 10.12 years (SD = 3.59), mean implantation age of 1.36 years (SD = 0.46), and mean CI experience of 6.23 years (SD = 1.75). Children in all three studies completed a self-report quality-of-life questionnaire that included seven benefit and six problem items, rated on a 5-point Likert scale. RESULTS: Outcomes revealed agreement across studies in overall benefit and problem ratings. Environmental awareness and frustration reduction were the most and least positively rated outcomes, respectively. Items contributing to overall ratings differed across studies. Current CI recipients rated speech production, making new friends, and understanding speech more positively and taking extra care of the device more negatively than previous generations of pediatric CI users. DISCUSSION: Overall, benefits outweigh problems of the device, according to children using CI. Differences in issues motivating self-report ratings reflect changes in CI candidacy, technology, and social participation over the past decade. These findings emphasize the need for clinicians to address not only communication needs, but also quality-of-life issues to optimize outcomes in children using CI.

Effects of maternal sensitivity and cognitive and linguistic stimulation on cochlear implant users' language development over four years.

OBJECTIVES: To examine the effects of observed maternal sensitivity (MS), cognitive stimulation (CS), and linguistic stimulation on the 4-year growth of oral language in young, deaf children receiving a cochlear implant. Previous studies of cochlear implants have not considered the effects of parental behaviors on language outcomes. STUDY DESIGN: In this prospective, multisite study, we evaluated parent-child interactions during structured and unstructured play tasks and their effects on oral language development in 188 deaf children receiving a cochlear implant and 97 normal-hearing children as controls. Parent-child interactions were rated on a 7-point scale using the National Institute of Child Health and Human Development's Early Childcare Study codes, which have well-established psychometric properties. Language was assessed using the MacArthur Bates Communicative Development Inventories, the Reynell Developmental Language Scales, and the Comprehensive Assessment of Spoken Language. RESULTS: We used mixed longitudinal modeling to test our hypotheses. After accounting for early hearing experience and child and family demographics, MS and CS predicted significant increases in the growth of oral language. Linguistic stimulation was related to language growth only in the context of high MS. CONCLUSION: The magnitude of effects of MS and CS on the growth of language was similar to that found for age at cochlear implantation, suggesting that addressing parenting behaviors is a critical target for early language learning after implantation.

Cochlear implantation updates: the Dallas Cochlear Implant Program.

This report provides an overview of many research projects conducted by the Dallas Cochlear Implant Program, a joint enterprise between the University of Texas at Dallas, the University of Texas Southwestern Medical Center, and Children's Medical Center. The studies extend our knowledge of factors influencing communication outcomes in users of cochlear implants. Multiple designs and statistical techniques are used in the studies described including both cross sectional and longitudinal analyses. Sample sizes vary across the studies, and many of the samples represent large populations of children from North America. Multiple statistical techniques are used by the team to analyze outcomes. The team has provided critical information regarding electrode placement, signal processing, and communication outcomes in users of cochlear implants.

Timing of cochlear implantation and parents' global ratings of children's health and development.

OBJECTIVE: To assess children's health-related quality of life (HRQL) and development after cochlear implant (CI) surgery and compare improvements between different age of implantation categories. STUDY DESIGN: Prospective, longitudinal study comparing outcomes of deaf children post-CI with hearing controls. SETTING: Six US CI centers. PATIENTS: Deaf children who received CI (n = 188) and hearing children of comparable ages (n = 97). INTERVENTION: CI before 5 years of age. MAIN OUTCOME MEASURE: Parental ratings of global HRQL and development, as assessed over the first 4 years of follow-up using visual analog scales. Development scores assess parental views of children's growth and development, motor skills, ability to express themselves and communicate with others, and learning abilities. Associations of baseline child and family characteristics with post-CI HRQL and development were investigated using multivariable analysis, controlling for factors that influence post-CI language learning. RESULTS: Baseline deficits of CI candidates relative to hearing controls were larger in development than HRQL. Development scores improved significantly by 4 years after CI, particularly in the youngest CI recipients. Developmental deficits of older CI recipients with early, extended hearing aid use were only partially remediated by CI. Overall, no significant health deficits were observed in CI children after 4 years. Cognition and speech recognition were positively associated with both HRQL and development. CONCLUSION: Parental perspectives on quality of their child's life and development provide practical insight into the optimal timing of interventions for early-onset deafness. Validity of parental global assessments is supported by clinical measures of speech perception and language learning and comparison with a well-validated health status instrument.

Language development after cochlear implantation: an epigenetic model.

Growing evidence supports the notion that dynamic gene expression, subject to epigenetic control, organizes multiple influences to enable a child to learn to listen and to talk. Here, we review neurobiological and genetic influences on spoken language development in the context of results of a longitudinal trial of cochlear implantation of young children with severe to profound sensorineural hearing loss in the Childhood Development after Cochlear Implantation study. We specifically examine the results of cochlear implantation in participants who were congenitally deaf (N = 116). Prior to intervention, these participants were subject to naturally imposed constraints in sensory (acoustic-phonologic) inputs during critical phases of development when spoken language skills are typically achieved rapidly. Their candidacy for a cochlear implant was prompted by delays (n = 20) or an essential absence of spoken language acquisition (n = 96). Observations thus present an opportunity to evaluate the impact of factors that influence the emergence of spoken language, particularly in the context of hearing restoration in sensitive periods for language acquisition. Outcomes demonstrate considerable variation in spoken language learning, although significant advantages exist for the congenitally deaf children implanted prior to 18 months of age. While age at implantation carries high predictive value in forecasting performance on measures of spoken language, several factors show significant association, particularly those related to parent-child interactions. Importantly, the significance of environmental variables in their predictive value for language development varies with age at implantation. These observations are considered in the context of an epigenetic model in which dynamic genomic expression can modulate aspects of auditory learning, offering insights into factors that can influence a child's acquisition of spoken language after cochlear implantation. Increased understanding of these interactions could lead to targeted interventions that interact with the epigenome to influence language outcomes with intervention, particularly in periods in which development is subject to time-sensitive experience.