Cochlear implantation of children with minimal open-set speech recognition skills

Two are better than one: Differences in cortical EEG patterns during auditory and visual verbal working memory processing between Unilateral and Bilateral Cochlear Implanted children

Despite the proven effectiveness of cochlear implant (CI) in the hearing restoration of deaf or hard-of-hearing (DHH) children, to date, extreme variability in verbal working memory (VWM) abilities is observed in both unilateral and bilateral CI user children (CIs). Although clinical experience has long observed deficits in this fundamental executive function in CIs, the cause to date is still unknown. Here, we have set out to investigate differences in brain functioning regarding the impact of monaural and binaural listening in CIs compared with normal hearing (NH) peers during a three-level difficulty n-back task undertaken in two sensory modalities (auditory and visual). The objective of this pioneering study was to identify electroencephalographic (EEG) marker pattern differences in visual and auditory VWM performances in CIs compared to NH peers and possible differences between unilateral cochlear implant (UCI) and bilateral cochlear implant (BCI) users. The main results revealed differences in theta and gamma EEG bands. Compared with hearing controls and BCIs, UCIs showed hypoactivation of theta in the frontal area during the most complex condition of the auditory task and a correlation of the same activation with VWM performance. Hypoactivation in theta was also observed, again for UCIs, in the left hemisphere when compared to BCIs and in the gamma band in UCIs compared to both BCIs and NHs. For the latter two, a correlation was found between left hemispheric gamma oscillation and performance in the audio task. These findings, discussed in the light of recent research, suggest that unilateral CI is deficient in supporting auditory VWM in DHH. At the same time, bilateral CI would allow the DHH child to approach the VWM benchmark for NH children. The present study suggests the possible effectiveness of EEG in supporting, through a targeted approach, the diagnosis and rehabilitation of VWM in DHH children.

Effects of residual hearing on cochlear implant outcomes in children: A systematic-review

OBJECTIVES

to investigate if preoperative residual hearing in prelingually deafened children can interfere on cochlear implant indication and outcomes.

METHODS

a systematic-review was conducted in five international databases up to November-2016, to locate articles that evaluated cochlear implantation in children with some degree of preoperative residual hearing. Outcomes were auditory, language and cognition performances after cochlear implant. The quality of the studies was assessed and classified according to the Oxford Levels of Evidence table - 2011. Risk of biases were also described.

RESULTS

From the 30 articles reviewed, two types of questions were identified: (a) what are the benefits of cochlear implantation in children with residual hearing? (b) is the preoperative residual hearing a predictor of cochlear implant outcome? Studies ranged from 04 to 188 subjects, evaluating populations between 1.8 and 10.3 years old. The definition of residual hearing varied between studies. The majority of articles (n = 22) evaluated speech perception as the outcome and 14 also assessed language and speech production.

CONCLUSION

There is evidence that cochlear implant is beneficial to children with residual hearing. Preoperative residual hearing seems to be valuable to predict speech perception outcomes after cochlear implantation, even though the mechanism of how it happens is not clear. More extensive researches must be conducted in order to make recommendations and to set prognosis for cochlear implants based on children preoperative residual hearing.

Mandarin Lexical Tone Acquisition in Cochlear Implant Users With Prelingual Deafness: A Review

PURPOSE

The purpose of this review article is to synthesize evidence from the fields of developmental linguistics and cochlear implant technology relevant to the production and perception of Mandarin lexical tone in cochlear implant users with prelingual deafness. The aim of this review was to identify potential factors that determine outcomes for tonal-language speaking cochlear implant users and possible directions for further research.

METHOD

A computerized database search of MEDLINE, CINAHL, Academic Search Premier, Web of Science, and Google Scholar was undertaken in June and July 2014. Search terms used were lexical tone AND tonal language, speech development AND/OR speech production AND/OR speech perception AND cochlear implants, and pitch perception AND cochlear implants, anywhere in the title or abstract.

CONCLUSION

Despite the demonstrated limitations of pitch perception in cochlear implant users, there is some evidence that typical production and perception of lexical tone is possible by cochlear implant users with prelingual deafness. Further studies are required to determine the factors that contribute to better outcomes to inform rehabilitation processes for cochlear implant users in tonal-language environments.

A Prospective Longitudinal Study of U.S. Children Unable to Achieve Open-Set Speech Recognition 5 Years After Cochlear Implantation

OBJECTIVE

To identify characteristics associated with the inability to progress to open-set speech recognition in children 5 years after cochlear implantation.

STUDY DESIGN

Prospective, longitudinal, and multidimensional assessment of auditory development for 5 years.

SETTING

Six tertiary cochlear implant (CI) referral centers in the United States.

PATIENTS

Children with severe-to-profound hearing loss who underwent implantation before age 5 years enrolled in the Childhood Development after Cochlear Implantation study, categorized by level of speech recognition ability.

INTERVENTION(S)

Cochlear implantation before 5 years of age and annual assessment of emergent speech recognition skills.

MAIN OUTCOME MEASURE(S)

Progression to open-set speech recognition by 5 years after implantation.

RESULTS

Less functional hearing before implantation, older age at onset of amplification, lower maternal sensitivity to communication needs, minority status, and complicated perinatal history were associated with the inability to obtain open-set speech recognition by 5 years.

CONCLUSION

Characteristics of a subpopulation of children with CIs associated with an inability to achieve open-set speech recognition after 5 years of CI experience were investigated. These data distinguish pediatric CI recipients at risk for poor auditory development and highlight areas for future interventions to enhance support of early implantation.

A semi-supervised Support Vector Machine model for predicting the language outcomes following cochlear implantation based on pre-implant brain fMRI imaging

INTRODUCTION

We developed a machine learning model to predict whether or not a cochlear implant (CI) candidate will develop effective language skills within 2 years after the CI surgery by using the pre-implant brain fMRI data from the candidate.

METHODS

The language performance was measured 2 years after the CI surgery by the Clinical Evaluation of Language Fundamentals-Preschool, Second Edition (CELF-P2). Based on the CELF-P2 scores, the CI recipients were designated as either effective or ineffective CI users. For feature extraction from the fMRI data, we constructed contrast maps using the general linear model, and then utilized the Bag-of-Words (BoW) approach that we previously published to convert the contrast maps into feature vectors. We trained both supervised models and semi-supervised models to classify CI users as effective or ineffective.

RESULTS

Compared with the conventional feature extraction approach, which used each single voxel as a feature, our BoW approach gave rise to much better performance for the classification of effective versus ineffective CI users. The semi-supervised model with the feature set extracted by the BoW approach from the contrast of speech versus silence achieved a leave-one-out cross-validation AUC as high as 0.97. Recursive feature elimination unexpectedly revealed that two features were sufficient to provide highly accurate classification of effective versus ineffective CI users based on our current dataset.

CONCLUSION

We have validated the hypothesis that pre-implant cortical activation patterns revealed by fMRI during infancy correlate with language performance 2 years after cochlear implantation. The two brain regions highlighted by our classifier are potential biomarkers for the prediction of CI outcomes. Our study also demonstrated the superiority of the semi-supervised model over the supervised model. It is always worthwhile to try a semi-supervised model when unlabeled data are available.

Are Auditory Steady-State Responses Useful to Evaluate Severe-to-Profound Hearing Loss in Children?

Objective. To evaluate Auditory Steady-State Responses (ASSR) at high intensities in pediatric cochlear implant candidates and to compare the results to behavioral tests responses. Methods. This prospective study evaluated 42 children with suspected severe-to-profound hearing loss, aged from 3 to 72 months. All had absent ABR and OAE responses. ASSR were evoked using binaural single frequency stimuli at 110 dB HL with a 10 dB down-seeking procedure. ASSR and behavioral test results were compared. Results. Forty-two subjects completed both ASSR and behavioral evaluation. Eleven children (26.2%) had bilateral responses. Four (9.5%) showed unilateral responses in at least two frequencies, all confirmed by behavioral results. Overall 61 ASSR responses were obtained, most (37.7%) in 500 Hz. Mean thresholds were between 101.3 and 104.2 dB HL. Among 27 subjects with absent ASSR, fifteen had no behavioral responses. Seven subjects showed behavioral responses with absent ASSR responses. No spurious ASSR responses were observed at 100 or 110 dB HL. Conclusion. ASSR is a valuable tool to detect residual hearing. No false-positive ASSR results were observed among 42 children, but in seven cases with absent ASSR, the test underestimated residual hearing as compared to the behavioral responses.

Pediatric Cochlear Implantation in Residual Hearing Candidates

Objectives:

To propose categories for the various types of residual hearing in children and to review the outcomes of cochlear implantation (CI) in children with these different hearing conditions.

Methods:

We identified 53 children with residual hearing who had received a cochlear implant. Five groups were arbitrarily defined based on auditory features: G1, characterized by low-frequency residual hearing (n = 5); G2, characterized by severe sensorineural hearing loss (SNHL) and low speech discrimination (n = 12); G3, characterized by asymmetric SNHL (n = 9); G4, characterized by progressive SNHL (n = 15); and G5, characterized by fluctuating SNHL (n = 12). The main audiometric features and outcomes of the groups were analyzed.

Results:

The mean age at implantation was 10.15 years (range, 2.5-21 years). The mean preoperative score for the discrimination of open-set words was 48%; this score increased to 74% at 12 months and 81% at 24 months after the CI procedure (G1 to G5, respectively: 79/62/77%, 50/81/88%, 59/75/86%, 35/74/67%, and 39/69/80%). Children who were implanted after 10 years of age did not improve as much as those who were implanted at a younger age (open-set word list speech perception [OSW] score at 12 months: 62% vs 83%; P = .0009). Shorter delays before surgery were predictive of better performance ( P = .003). Inner ear malformation and SLC26A4 mutations were not predictive of the outcome.

Conclusions:

CIs provide better results compared with hearing aids in children with residual hearing. Factors that may impact the benefits of CIs in patients with residual hearing are age, delay in performing the CI procedure, which ear is implanted, and initial underestimation of the patient’s hearing difficulties.

Communication development in children who receive a cochlear implant by 12 months of age

OBJECTIVE

Describe the long-term benefits of early cochlear implantation. Provide a comprehensive description of outcomes, including: language, speech production, and speech perception. Compare the communication outcomes for the early implanted children to those of normally hearing children and children who received a cochlear implant at a comparatively older age.

METHOD

Retrospective review of the communication development of 35 children implanted between 6 and 12 months of age and 85 children implanted between 13 and 24 months of age. Audiologic assessments included unaided and aided audiograms, auditory brainstem response (ABR), auditory steady state response (ASSR), and otoacoustic emissons (OAEs). Formal language, speech production, and speech perception measures were administered, preimplant and at 1, 2, 3, and 5 years postimplant.

RESULTS

The children who received their cochlear implant by 12 months of age demonstrated language growth rates equivalent to their normally hearing peers and achieved age appropriate receptive language scores 3 years postimplant. The children who received their cochlear implant between 13 and 24 months demonstrated a significant language delay at 3 years postimplant. Speech production development followed a similar pattern to that of normal-hearing children, although was delayed, for both groups of children. Mean open-set speech perception scores were comparable with previous reports for children and adults who use cochlear implants.

CONCLUSION

Children implanted by 12 months of age demonstrate better language development compared with children who receive their cochlear implant between 13 and 24 months. This supports the provision of a cochlear implant within the first year of life to enhance the likelihood that a child with severe-to-profound hearing impairment will commence elementary school with age-appropriate language skills.

Cochlear implants: clinical and societal outcomes

Over the past 30 years, hearing care clinicians have increasingly relied on cochlear implants to restore auditory sensitivity in selected patients with advanced sensorineural hearing loss. This article examines the impact of intervention with cochlear implantation in children and adults. The authors report a range of clinic-based results and patient-based outcomes reflected in the reported literature on cochlear implants. The authors describe the basic assessment of the physiologic response to auditory nerve stimulation; measures of receptive and productive benefit; and surveys of life effects as reflected measures of quality of life, educational attainment, and economic impact.

Pediatric cochlear implantation: candidacy evaluation, medical and surgical considerations, and expanding criteria

Since the first cochlear implant approved by the US Food and Drug Administration in the early 1980s, great advances have occurred in cochlear implant technology. With these advances, patient selection, preoperative evaluation, and rehabilitation consideration continue to evolve. This article describes the current practice in pediatric candidacy evaluation, reviews the medical and surgical considerations in pediatric cochlear implantation, and explores the expanding criteria for cochlear implantation within the pediatric population.

Expected test scores for preschoolers with a cochlear implant who use spoken language

PURPOSE

The major purpose of this study was to provide information about expected spoken language skills of preschool-age children who are deaf and who use a cochlear implant. A goal was to provide "benchmarks" against which those skills could be compared, for a given age at implantation. We also examined whether parent-completed checklists of children's language were correlated with results of standardized language tests and whether scores increased linearly with decreasing age of implantation and increasing duration of cochlear implant use.

METHOD

Participants were a nationwide sample of 76 children who were deaf and orally educated and who received an implant by 38 months of age. Formal language tests were administered at age 4.5 years. The MacArthur-Bates Communicative Development Inventories (CDI) instrument was completed by parents when children were ages 3.5 and 4.5 years.

RESULTS

Based on regression analyses, expected scores for each age at implant were provided for 2 commonly administered language tests at 4.5 years of age and CDI subscale scores at 3.5 and 4.5 years. Concurrent test scores were significantly correlated on all measures. A linear relation was found that predicted increasing test scores with younger ages at implantation for all scales administered.

CONCLUSIONS

While the expected scores reported here should not be considered as normative data, they are benchmarks that may be useful for evaluating spoken language progress of children with cochlear implants who are enrolled in spoken language-based programs.

Will they catch up? The role of age at cochlear implantation in the spoken language development of children with severe to profound hearing loss

PURPOSE

The authors examined the benefits of younger cochlear implantation, longer cochlear implant use, and greater pre-implant aided hearing to spoken language at 3.5 and 4.5 years of age.

METHOD

Language samples were obtained at ages 3.5 and 4.5 years from 76 children who received an implant by their 3rd birthday. Hierarchical linear modeling was used to identify characteristics associated with spoken language outcomes at the 2 test ages. The Preschool Language Scale (I. L. Zimmerman, V. G. Steiner, & R. E. Pond, 1992) was used to compare the participants' skills with those of hearing age-mates at age 4.5 years.

RESULTS

Expected language scores increased with younger age at implant and lower pre-implant thresholds, even when compared at the same duration of implant use. Expected Preschool Language Scale scores of the children who received the implant at the youngest ages reached those of hearing age-mates by 4.5 years, but those children implanted after 24 months of age did not catch up with hearing peers.

CONCLUSION

Children who received a cochlear implant before a substantial delay in spoken language developed (i.e., between 12 and 16 months) were more likely to achieve age-appropriate spoken language. These results favor cochlear implantation before 24 months of age, especially for children with aided pure-tone average thresholds greater than 65 dB prior to surgery.

Effects of early auditory experience on the spoken language of deaf children at 3 years of age

OBJECTIVE

By age 3, typically developing children have achieved extensive vocabulary and syntax skills that facilitate both cognitive and social development. Substantial delays in spoken language acquisition have been documented for children with severe to profound deafness, even those with auditory oral training and early hearing aid use. This study documents the spoken language skills achieved by orally educated 3-yr-olds whose profound hearing loss was identified and hearing aids fitted between 1 and 30 mo of age and who received a cochlear implant between 12 and 38 mo of age. The purpose of the analysis was to examine the effects of age, duration, and type of early auditory experience on spoken language competence at age 3.5 yr.

DESIGN

The spoken language skills of 76 children who had used a cochlear implant for at least 7 mo were evaluated via standardized 30-minute language sample analysis, a parent-completed vocabulary checklist, and a teacher language-rating scale. The children were recruited from and enrolled in oral education programs or therapy practices across the United States. Inclusion criteria included presumed deaf since birth, English the primary language of the home, no other known conditions that interfere with speech/language development, enrolled in programs using oral education methods, and no known problems with the cochlear implant lasting more than 30 days.

RESULTS

Strong correlations were obtained among all language measures. Therefore, principal components analysis was used to derive a single Language Factor score for each child. A number of possible predictors of language outcome were examined, including age at identification and intervention with a hearing aid, duration of use of a hearing aid, pre-implant pure-tone average (PTA) threshold with a hearing aid, PTA threshold with a cochlear implant, and duration of use of a cochlear implant/age at implantation (the last two variables were practically identical because all children were tested between 40 and 44 mo of age). Examination of the independent influence of these predictors through multiple regression analysis revealed that pre-implant-aided PTA threshold and duration of cochlear implant use (i.e., age at implant) accounted for 58% of the variance in Language Factor scores. A significant negative coefficient associated with pre-implant-aided threshold indicated that children with poorer hearing before implantation exhibited poorer language skills at age 3.5 yr. Likewise, a strong positive coefficient associated with duration of implant use indicated that children who had used their implant for a longer period of time (i.e., who were implanted at an earlier age) exhibited better language at age 3.5 yr. Age at identification and amplification was unrelated to language outcome, as was aided threshold with the cochlear implant. A significant quadratic trend in the relation between duration of implant use and language score revealed a steady increase in language skill (at age 3.5 yr) for each additional month of use of a cochlear implant after the first 12 mo of implant use. The advantage to language of longer implant use became more pronounced over time.

CONCLUSIONS

Longer use of a cochlear implant in infancy and very early childhood dramatically affects the amount of spoken language exhibited by 3-yr-old, profoundly deaf children. In this sample, the amount of pre-implant intervention with a hearing aid was not related to language outcome at 3.5 yr of age. Rather, it was cochlear implantation at a younger age that served to promote spoken language competence. The previously identified language-facilitating factors of early identification of hearing impairment and early educational intervention may not be sufficient for optimizing spoken language of profoundly deaf children unless it leads to early cochlear implantation.

Examining multiple sources of influence on the reading comprehension skills of children who use cochlear implants

Children with profound deafness are at risk for serious reading difficulties. Multiple factors affect their development of reading skills, including use of cochlear implants. Further, multiple factors influence the overall success that children experience with their cochlear implants. These factors include the age at which they receive an implant, method of communication, vocabulary skills, preoperative residual hearing, and socioeconomic status. Ninety-one children with prelingual and profound hearing impairments who received cochlear implants at varying ages participated in the study. Structural equation modeling confirmed that multiple factors affected young cochlear implant users' reading comprehension skills and that there were significant associations between the predictors of reading comprehension. Pre-implant vocabulary had an indirect positive effect on reading through postimplant vocabulary, which had a direct positive effect on reading. Overall, children with stronger language skills demonstrated stronger reading outcomes. Age at implantation both directly and indirectly, through postimplant vocabulary, affected reading outcomes, and the total effect was large. Children who were younger when they received their implants tended to have higher reading comprehension scores. Socioeconomic status negatively affected reading. Children who used total communication prior to implantation tended to have stronger pre-implant vocabulary scores, but the total effect of pre-implant communication method on children's reading skills was negligible. Research and educational implications are discussed.

Cochlear Implantation for the Treatment of Deafness

Cochlear implants have dramatically changed the treatment and prognosis for patients with profound sensorineural hearing loss. Deaf adults and children can be successfully (re)integrated into the hearing world through a multidisciplinary approach involving otolaryngologists, audiologists, and speech/language pathologists. As the technology of the cochlear prosthesis advances, the candidacy for these devices continues to broaden. This review addresses the basic technology, candidacy criteria, and important issues in the fields of adult and pediatric cochlear implantation. Cost utility and future directions in the treatment of the profoundly hearing impaired are discussed.

Cochlear implants in young children

The cochlear implant is best characterized as a device that provides access to the sound environment. The device enables the hearing pathway to respond to environmental and speech sounds, providing informational cues from the surroundings and from others that may escape visual detection. As the developmental effects of a profound hearing loss are multiple, cochlear implants have been applied to ever younger children in an attempt to promote a more normal level of developmental learning through audition. In deafness, transducer elements of the inner ear fail to trigger auditory nerve afferent nerves in the presence of sound input. However, large reserves of afferent fibers exist even in the auditory nerve of a profoundly deaf patient. Furthermore, these nerve fibers retain the ability to respond to prosthetic activation. Through developmental learning in the early, formative years, auditory centers of the brain appear capable of processing information from the implant to provide speech comprehension and oral language development. Multichannel implants have replaced original single channel designs. multichannel devices enable larger percentages of recipients to recognize the spoken word without visual cues because they provide spectral information in addition to temporal and intensity cues. Testing under conditions of auditory (implant)-only input reveals significant open-set speech understanding capabilities in more than 75% of children after three years of device use. The benefit provided by implants may vary with a number of conditions including: hearing history, age of deafness onset, age at implantation, etiology of deafness, linguistic abilities, and the presence of a motivated system of support of oral language development. Patient variables should be given individual consideration in judging candidacy for a cochlear implant and in planning rehabilitative and education services after surgery and activation of the device.

Cochlear implantation in prelingually deaf children with ossified cochleae

OBJECTIVE

To evaluate the effects that degree of cochlear ossification has on performance of prelingually deafened children who receive cochlear implants.

STUDY DESIGN

A matched-pairs analysis comparing speech perception results obtained 6 and 24 months after implant by children with ossified and nonossified cochleae. Additionally, long-term performance was evaluated in patients with follow-up periods longer than 24 months. Comparisons were also performed within the ossified cochleae group to determine if degree of cochlear ossification and surgical technique affected outcome with the cochlear implant. SETTING Large cochlear implant program in an academic tertiary care medical center.

PATIENTS

Twenty-one pairs of prelingually deaf children with and without cochlear ossification. Meningitis was the etiology of hearing loss in children with ossified cochleae. The control group had nonmeningitic etiology for the hearing loss.

INTERVENTIONS

Multichannel cochlear implantation and routine postoperative auditory rehabilitation and performance evaluation.

MAIN OUTCOME MEASURES

Speech perception category ratings based on scores obtained on a battery of closed- and open-set speech recognition tests 6 and 24 months after implant. Longer follow-up period is also reported.

RESULTS

As a group, children with cochlear ossification showed significant improvement in their speech perception abilities 6 and 24 months after implant. Children with cochlear ossification performed at a significantly lower speech perception category than a group of matched controls with nonossified cochleae at both the 6- and 24-month postimplant intervals. With longer implant use, open-set speech recognition was possible in some children with ossification. Within-group analysis of the children with ossified cochleae revealed that degree of ossification and surgical procedure used for implantation did not significantly affect outcome.

CONCLUSIONS

Prelingually deafened children with postmeningitic hearing loss and ossified cochleae receive significant benefit from cochlear implants. Their performance is frequently poorer, however, than children with nonossified cochleae.

Background and educational characteristics of prelingually deaf children implanted by five years of age

PURPOSE

This study documents child, family and educational characteristics of a large representative sample of 8- to 9-yr-old prelingually deaf children who received a cochlear implant by 5 yr of age. Because pre-existing factors such as the child's gender, family characteristics, additional handicaps, age at onset of deafness and at implant, may affect postimplant outcomes, these variables must be accounted for before the impact of educational factors on performance with an implant can be adequately determined. Classroom variables that may affect postimplant outcomes include placement in public or private, mainstream or special education, oral or total communication environments. Other intervention variables include type and amount of individual therapy, experience of the therapist and parent participation in therapy. Documenting these characteristics for a large representative sample of implanted children can provide clinicians and researchers with insight regarding the types of families who sought early cochlear implantation for their children and the types of educational programs in which they placed their children after implantation. It is important to undertake studies that control for as many of these factors as possible so that the relative benefits of specific educational approaches for helping children to get the most benefit from their cochlear implant can be identified.

METHOD

Over a 4-yr period, 181 children from across the US and Canada, accompanied by a parent, attended a cochlear implant research camp. Parents completed questionnaires in which they reported the child's medical and educational history, characteristics of the family, and their participation in the child's therapy. The parent listed names and addresses of clinicians who had provided individual speech/language therapy to the child and signed permission for these clinicians to complete questionnaires describing this therapy.

RESULTS

To the extent that this sample is representative of those families seeking a cochlear implant for their child, especially during the initial period of device availability, this population can be characterized as follows. Most parents had normal hearing, were of majority (white) ethnicity and had more education and higher incomes than the general population. The families tended to be intact with both a mother and a father who involved their hearing-impaired child in family activities on a regular basis. The children were enrolled in the full range of educational placements available across the United States and Canada. Fairly even distributions of children from public and private schools, special education and mainstream classes and oral and total communication methodologies were represented. Educational placement changed as children gained increased experience with a cochlear implant. They received an increased emphasis on speech and auditory skills in their classroom settings and tended to move from private school and special education settings to public school and mainstream programs. These data support the position that early cochlear implantation is a cost effective procedure that allows deaf children to participate in a normal school environment with hearing age mates.

Measures of working memory span and verbal rehearsal speed in deaf children after cochlear implantation

Large individual differences in spoken word recognition performance have been found in deaf children after cochlear implantation. Recently, Pisoni and Geers (2000) reported that simple forward digit span measures of verbal working memory were significantly correlated with spoken word recognition scores even after potentially confounding variables were statistically controlled for. The present study replicates and extends these initial findings to the full set of 176 participants in the CID cochlear implant study. The pooled data indicate that despite statistical "partialling-out" of differences in chronological age, communication mode, duration of deafness, duration of device use, age at onset of deafness, number of active electrodes, and speech feature discrimination, significant correlations still remain between digit span and several measures of spoken word recognition. Strong correlations were also observed between speaking rate and both forward and backward digit span, a result that is similar to previously reported findings in normal-hearing adults and children. The results suggest that perhaps as much as 20% of the currently unexplained variance in spoken word recognition scores may be independently accounted for by individual differences in cognitive factors related to the speed and efficiency with which phonological and lexical representations of spoken words are maintained in and retrieved from working memory. A smaller percentage, perhaps about 7% of the currently unexplained variance in spoken word recognition scores, may be accounted for in terms of working memory capacity. We discuss how these relationships may arise and their contribution to subsequent speech and language development in prelingually deaf children who use cochlear implants.

Cochlear implants in children--a review

Over the past two decades, cochlear implantation has become a widely accepted treatment of deafness in children. Over 20,000 children have received cochlear implants worldwide. Hearing, language and social development outcomes have been positive. We review current issues in cochlear implantation, candidacy, evaluation, surgery, habilitation, ethics and outcomes.

Cochlear implantation in prelingually deafened children with residual hearing

OBJECTIVE

The purpose of this study was to examine the speech perception skills of prelingually deafened French children with preoperative residual hearing who received multichannel cochlear implants.

DESIGN

The design of the study incorporated a within-subject, repeated measures design for assessing speech perception skills.

SETTING

Montpellier, Toulouse and Lyon Pediatric Cochlear Implant Centers.

SUBJECTS

Seven prelingually deafened children demonstrating marginal benefit from conventional amplification prior to implantation with a Nucleus multichannel cochlear implant, served as subjects for the speech perception assessment (a speech recognition score less than 30% defines marginal benefit from acoustic amplification on open set materials). The mean age at implantation was 7 years, 9 months.

OUTCOME MEASURES

Speech perception skills were assessed using open set materials and the MUSS and MAIS questionnaires.

RESULTS

Open-set speech recognition averaged 21.4% before implantation, and 83.6% after 1 year's cochlear implant experience. All children demonstrated an open-set score over 60% after 12 months of CI use. MAIS test scores averaged 18.1/40 before implantation and 35.1/40 after 9 months of CI use. MUSS test scores averaged 24.4/40 before implantation and 34.1/40 after 9 months of CI use.

CONCLUSIONS

Cochlear implantation should be considered for prelingually hearing impaired children demonstrating marginal benefit from hearing aids, with a speech recognition score less than 30% on open set materials, in order to improve their speech discrimination skills.

Universal newborn hearing screening coming soon: "hear's" why

Screening the hearing of all newborns, both NICU and well nursery, is rapidly becoming the standard of care. The impetus for universal newborn hearing screening (UNHS) has come from outside the domain of nursing and the newborn nursery. Because nursing will be involved in nearly all aspects of UNHS, nurses need a thorough knowledge base about permanent childhood hearing loss (PCHL) and UNHS. Technology exisits today that can objectively and physiologically screen for this condition at a cost comparable to metabolic screening. PCHL occurs more than twice as often as all the hemoglobinopathies and inborn errors of metabolism combined. Undiagnosed hearing loss often leads to permanent developmental delays. The ultimate goal of early diagnosis and intervention for a congenital hearing loss is to enable the child to develop language and communication skills that correspond to his chronological age and innate cognitive abilities.

Some measures of verbal and spatial working memory in eight- and nine-year-old hearing-impaired children with cochlear implants

OBJECTIVE

The purpose of this study was to examine working memory for sequences of auditory and visual stimuli in prelingually deafened pediatric cochlear implant users with at least 4 yr of device experience.

DESIGN

Two groups of 8- and 9-yr-old children, 45 normal-hearing and 45 hearing-impaired users of cochlear implants, completed a novel working memory task requiring memory for sequences of either visual-spatial cues or visual-spatial cues paired with auditory signals. In each sequence, colored response buttons were illuminated either with or without simultaneous auditory presentation of verbal labels (color-names or digit-names). The child was required to reproduce each sequence by pressing the appropriate buttons on the response box. Sequence length was varied and a measure of memory span corresponding to the longest list length correctly reproduced under each set of presentation conditions was recorded. Additional children completed a modified task that eliminated the visual-spatial light cues but that still required reproduction of auditory color-name sequences using the same response box. Data from 37 pediatric cochlear implant users were collected using this modified task.

RESULTS

The cochlear implant group obtained shorter span scores on average than the normal-hearing group, regardless of presentation format. The normal-hearing children also demonstrated a larger "redundancy gain" than children in the cochlear implant group-that is, the normal-hearing group displayed better memory for auditory-plus-lights sequences than for the lights-only sequences. Although the children with cochlear implants did not use the auditory signals as effectively as normal-hearing children when visual-spatial cues were also available, their performance on the modified memory task using only auditory cues showed that some of the children were capable of encoding auditory-only sequences at a level comparable with normal-hearing children.

CONCLUSIONS

The finding of smaller redundancy gains from the addition of auditory cues to visual-spatial sequences in the cochlear implant group as compared with the normal-hearing group demonstrates differences in encoding or rehearsal strategies between these two groups of children. Differences in memory span between the two groups even on a visual-spatial memory task suggests that atypical working memory development irrespective of input modality may be present in this clinical population.

Use of audiovisual information in speech perception by prelingually deaf children with cochlear implants: a first report

OBJECTIVE

Although there has been a great deal of recent empirical work and new theoretical interest in audiovisual speech perception in both normal-hearing and hearing-impaired adults, relatively little is known about the development of these abilities and skills in deaf children with cochlear implants. This study examined how prelingually deafened children combine visual information available in the talker's face with auditory speech cues provided by their cochlear implants to enhance spoken language comprehension.

DESIGN

Twenty-seven hearing-impaired children who use cochlear implants identified spoken sentences presented under auditory-alone and audiovisual conditions. Five additional measures of spoken word recognition performance were used to assess auditory-alone speech perception skills. A measure of speech intelligibility was also obtained to assess the speech production abilities of these children.

RESULTS

A measure of audiovisual gain, "Ra," was computed using sentence recognition scores in auditory-alone and audiovisual conditions. Another measure of audiovisual gain, "Rv," was computed using scores in visual-alone and audiovisual conditions. The results indicated that children who were better at recognizing isolated spoken words through listening alone were also better at combining the complementary sensory information about speech articulation available under audiovisual stimulation. In addition, we found that children who received more benefit from audiovisual presentation also produced more intelligible speech, suggesting a close link between speech perception and production and a common underlying linguistic basis for audiovisual enhancement effects. Finally, an examination of the distribution of children enrolled in Oral Communication (OC) and Total Communication (TC) indicated that OC children tended to score higher on measures of audiovisual gain, spoken word recognition, and speech intelligibility.

CONCLUSIONS

The relationships observed between auditory-alone speech perception, audiovisual benefit, and speech intelligibility indicate that these abilities are not based on independent language skills, but instead reflect a common source of linguistic knowledge, used in both perception and production, that is based on the dynamic, articulatory motions of the vocal tract. The effects of communication mode demonstrate the important contribution of early sensory experience to perceptual development, specifically, language acquisition and the use of phonological processing skills. Intervention and treatment programs that aim to increase receptive and productive spoken language skills, therefore, may wish to emphasize the inherent cross-correlations that exist between auditory and visual sources of information in speech perception.

Cochlear implants in children

Cochlear implants are electronic prostheses that provide a high quality sense of hearing to severely and profoundly deaf children and adults. As improvements in surgical technique and device performance have occurred, indications for implantation have expanded.

Audiophonological results after cochlear implantation in 40 congenitally deaf patients: preliminary results

The aim of this study is to evaluate the prognostic factors of audiophonological results in cochlear implant in congenitally deaf patients. Between 1991 and 1996. 40 congenitally deaf children underwent cochlear implantation in our department, at an average age of 7 years (median: 5 years). The results of speech therapy were evaluated with a mean follow-up of 2 years and were classified according to four criteria: perception of sound, speech perception, speech production and the level of oral language. For each criterion, a score was established ranging from zero to four. These scores were weighted according to age such that the results before and after implantation only reflected the changes related to the implantation. The prognostic factors for good results were: a good level of oral communication before implantation, residual hearing, progressive deafness and implantation at a young age. On the other hand, poor prognostic factors were: the presence of behavioral disorders and poor communication skills prior to implantation. Overall, the major prognostic factor for a good outcome appeared to be the preoperative level of oral language, even if this was rudimentary.

Cognitive factors and cochlear implants: some thoughts on perception, learning, and memory in speech perception

Over the past few years, there has been increased interest in studying some of the cognitive factors that affect speech perception performance of cochlear implant patients. In this paper, I provide a brief theoretical overview of the fundamental assumptions of the information-processing approach to cognition and discuss the role of perception, learning, and memory in speech perception and spoken language processing. The information-processing framework provides researchers and clinicians with a new way to understand the time-course of perceptual and cognitive development and the relations between perception and production of spoken language. Directions for future research using this approach are discussed including the study of individual differences, predicting success with a cochlear implant from a set of cognitive measures of performance and developing new intervention strategies.

Management of the child with sensorineural hearing loss. Medical, surgical, hearing aids, cochlear implants

Optimal comprehensive management of a child with SNHL involves constructive dialogue and coordination with the child's family and teachers. Not all children with SNHL benefit from conventional amplification, even after parents have invested significant amounts of money in hearing aids. Parents may encounter frustration and disappointment if their children fail to achieve communicative and academic goals they have established in their own mind. If the child is a potential candidate for cochlear implantation, this decision not only involves the risks (albeit modest) of surgery but also often a substantial financial commitment to help defray the cost of this sophisticated electronic device. The parents may encounter conflicting advice from friends and members of the adult deaf community about the benefit of cochlear implantation. Throughout the course of all of these difficult considerations, the health professionals caring for a child with hearing loss should be a source for information, guidance, and support to the family.

Improvements in speech perception by children with profound prelingual hearing loss: effects of device, communication mode, and chronological age

The present investigation expanded on an earlier study by Miyamoto, Osberger, Todd, Robbins, Karasek, et al. (1994) who compared the speech perception skills of two groups of children with profound prelingual hearing loss. The first group had received the Nucleus multichannel cochlear implant and was tested longitudinally. The second group, who were not implanted and used conventional hearing aids, was tested at a single point in time. In the present study, speech perception scores were examined over time for both groups of children as a function of communication mode of the child. Separate linear regressions of speech perception scores as a function of age were computed to estimate the rate of improvement in speech perception abilities that might be expected due to maturation for the hearing aid users (n=58) within each communication mode. The resulting regression lines were used to compare the estimated rate of speech perception growth for each hearing aid group to the observed gains in speech perception made by the children with multichannel cochlear implants. A large number of children using cochlear implants (n=74) were tested over a long period of implant use (m=3.5 years) that ranged from zero to 8.5 years. In general, speech perception scores for the children using cochlear implants were higher than those predicted for a group of children with 101-110 dB HL of hearing loss using hearing aids, and they approached the scores predicted for a group of children with 90-100 dB HL of hearing loss using hearing aids.