Selection of the optimal first ear for sequential bilateral cochlear implantation in children

OBJECTIVES

When there is a difference in hearing on both ears, where to perform the first cochlear implantation (CI) becomes an important issue. The purpose of the study was to evaluate which ear should be chosen for the first implantation in sequential bilateral CI with a long inter-implant period.

METHODS

The study population consisted of 34 severe-to-profound sensorineural hearing loss pediatrics with the inter-implant period of ≥3 years between the first CI (CI-1) and the second CI (CI-2) before the age of 19 (mean of inter-implant period: 7.1-year). The patients were classified into Group A (CI-1 was performed on the ear with better hearing), Group B (CI-1 on the ear with worse hearing), or Group C (symmetrical hearing in both ears). Speech intelligibility test results were compared between the groups.

RESULTS

The monosyllabic word scores of CI-1 were excellent in Groups A (91.7±7.9%) and B (92.5±3.6%) but slightly lower in Group C (85.7±14.9%) before the second implantation (P = .487). At 3 years after the second implantation, all groups demonstrated excellent scores in the bilateral CI condition (95.9±3.0% in Group A; 99.1±.8% in Group B; 97.5±2.9% in Group C, P = .600). However, when the patients were tested in using CI-2 only in Groups A and B after using bilateral CI for 3 years, the scores were inconsistent in Group A (79.6±23.9%; range: 22.2-94.4%), while those were higher and more constant in Group B (92.9±4.8%; 86.8-100.0%).

CONCLUSIONS

The first CI is strongly recommended to perform on a worse hearing ear if they had different hearing levels between ears. Even with the first CI on a worse hearing ear, its performance never deteriorates. In addition, if they receive the second CI several years later, it will be likely that the second one functions better.

Vestibular Preservation in Pediatric Cochlear Implantation

OBJECTIVES

Evaluate the rate of preserved vestibular function in pediatric cochlear implant surgery.

STUDY DESIGN

Retrospective case review.

METHODS

Pre- and post-operative vestibular tests were compared in children who underwent cochlear implantation at a tertiary level pediatric hospital over a 4-year period.

RESULTS

Data from 59 implanted ears in 44 children was included. Median age was 2.8 years at initial testing (range 7 months - 21 years) with 1:1 male/female ratio. Implant surgeries were 26 unilateral, 13 bilateral simultaneous, and 5 bilateral sequential. The majority were implanted with slim, non-styletted electrodes (86.4%) via a round window approach (91.5%). Normal pre-operative results were preserved post-operatively on rotary chair testing in 75% (21/28) of patients, cervical vestibular evoked myogenic potential testing in (75%) 30/40 of ears tested, ocular vestibular evoked myogenic potential testing in 85.7% (6/7) of ears tested, video head impulse testing in 100% (9/9) of ears tested, and computerized dynamic posturography in 100% (5/5) of patients tested. Overall, 62.5% of patients had no new deficits on any vestibular test performed post-operatively.

CONCLUSIONS

Preservation rates of vestibular function following cochlear implant surgery were higher in this cohort than what has been reported in many earlier studies. Contemporary, less traumatic electrodes and insertion techniques may be a significant factor. The risk of causing a new, severe bilateral vestibular loss with long-term functional impacts appears to be low. Further study is warranted on the impacts of different cochlear implant electrode designs and insertion approaches on post-operative vestibular preservation.

LEVEL OF EVIDENCE

4, Case Series Laryngoscope, 134:1913-1918, 2024.

Current Issues With Pediatric Cochlear Implantation

Cochlear implants (CIs) have demonstrated a clear functional benefit in children with severe-to-profound sensorineural hearing loss (SNHL) and thus have gained wide acceptance for treating deafness in the pediatric population. When evaluating young children for cochlear implantation, there are unique considerations beyond the standard issues addressed during surgery in adults. Because of advances in genetic testing, imaging resolution, CI technology, post-implant rehabilitation, and other factors, issues related to CI surgery in children continue to evolve. Such factors have led to changes in candidacy guidelines, vaccine requirements, and lowering of age requirement for surgery. In addition, differences in the anatomy and physiology of infants require special attention to ensure safety when operating on young children. This review summarizes these issues and provides guidance for surgeons treating children with SNHL.

Relationships between bilateral auditory brainstem activity and inter-implant interval in children with cochlear implants

PURPOSE

To investigate the effect of the interval between bilateral cochlear implantation on the development of bilateral peripheral auditory pathways as revealed by the electrically evoked auditory brainstem response (EABR).

METHODS

Fifty-eight children with profound bilateral sensorineural hearing loss were recruited. Among them, 33 children received sequential bilateral cochlear implants (CIs), and 25 children received simultaneous bilateral CIs. The bilateral EABRs evoked by electrical stimulation from the CI electrode were recorded on the day of second-side CI activation.

RESULTS

The latencies of wave III (eIII) and wave V (eV) were significantly shorter on the first CI side than on the second CI side in children with sequential bilateral CIs but were similar between the two sides in children with simultaneous bilateral CIs. Furthermore, the latencies were prolonged from apical to basal channels along the cochlea in the two groups. In children with sequential CIs, the inter-implant interval was negatively correlated with the eV latency on the first CI side and was positively correlated with bilateral differences in the eIII and eV latencies.

CONCLUSIONS

Unilateral CI use promotes the maturation of ipsilateral auditory conduction function. However, a longer inter-implant interval results in more unbalanced development of bilateral auditory brainstem pathways. Bilateral cochlear implantation with no or a short interval is recommended.

Bilateral simultaneous cochlear implants in children: Best timing of surgery and long-term auditory outcomes

PURPOSE

Evaluate the hearing outcomes of bilateral deaf children implanted simultaneously and define the most appropriate timing for surgery.

MATERIALS AND METHODS

Audiological CI results were retrieved in both the short-term and long-term period and compared by stratifying the patients into different subcohorts according to their age at surgery. Additional data collected were age at implant activation, etiology and timing of onset of deafness, presence of psychomotor delay.

RESULTS

fifty-six bilaterally implanted children were included. The short-term outcomes differed significantly when comparing groups of different ages at implantation: younger patients achieved better aided pure tone audiometry results. Considering long-term follow-up, a significant correlation was identified between an early age at implantation and the hearing outcome at ages 2 to 5 years. Perceptive levels were better at 4 years of age in the younger group. No significant differences were found between children implanted at before 12 months and between 12 and 16 months of age.

CONCLUSIONS

The results of the analyzed follow-up data support the hypothesis that children implanted at before 24 months are expected to have better hearing performances. Nevertheless, these results are referred to a widely heterogeneous group of patients and the duration of auditory deprivation should be considered.

Speech Perception of Second Cochlear Implant after 6 Years of Age in Prelingually Deaf Children

Sequential bilateral cochlear implantation in children becomes less effective as the inter-implant interval increases. However, the cause of this and the age at which speech perception becomes impossible are unclear. We examined the cases of 11 prelingually deaf children who underwent unilateral cochlear implantation at our hospitals before the age of 5 years old, followed by a second implantation procedure on the contralateral side when they were aged ≥ 6 years old (6-12 years old). The subjects' hearing thresholds and speech discrimination scores for the second cochlear implant were evaluated at 3 postoperative months and 1-7 years. All of the subjects demonstrated improvements in their hearing thresholds to a mean of 30 dB HL at 1 year. Regarding speech perception, one patient (a 12-year-old), who had developed bilateral hearing loss at 30 months of age after contracting mumps, demonstrated a 90% improvement in his speech discrimination score at 1 year. However, among the other congenitally deaf children, there were two patients whose speech discrimination scores had improved by ≥ 80% at > 4 postoperative years. The congenitally deaf children exhibited poor speech perception despite showing improved hearing thresholds in the ears that received second cochlear implants. Assuming that the auditory pathway beyond the superior olivary complex remained functional, the reduced speech perception abilities associated with the second cochlear implants may have been attributable to the loss of the spiral ganglion and cochlear nucleus cells due to a lack of auditory input since birth.

A longitudinal study of cortical auditory maturation and implications of the short inter-implant delay in children with bilateral sequential cochlear implants

OBJECTIVE

This longitudinal study aimed to investigate the maturational development of P1 latency and the effects of a short inter-implant delay in children who received bilateral sequential cochlear implants.

MATERIALS AND METHODS

Fourteen children (first CI mean age: 1.4 ± 0.4 years and Second CI mean age: 3.3 ± 0.5 years) who had received sequential bilateral cochlear implants during the sensitive period for auditory maturation participated in our study. The speech-evoked cortical P1 response was recorded after the activation of the second CI at four intervals (implant activation, 3 months, 6 months, 12 months) under three listening conditions (first CI, second CI, binaural).

RESULTS

Our results showed that the P1 latencies of the second CI reached normative values within 3 months, but did not reach the P1 latency of the first CI until 12 months. We found a strong negative correlation between the inter-implant delay and the P1 latencies of the second CI when the second CI was activated.

CONCLUSION

Changes in cortical auditory responses over time resulted in normal auditory maturation in children with sequential bilateral cochlear implants during the sensitive period. The results also provide evidence that the timing of auditory experience in the first ear during the sensitive period may influence the speed of compensation in children receiving sequential cochlear implants.

Factors affecting phoneme discrimination in children with sequential bilateral cochlear implants

OBJECTIVES

To investigate the effects of a number of variables on phoneme discrimination (PD) performance in children with sequential bilateral cochlear implants (SeqBiCIs) and compare PD performance between the 2 implantation sides and between children with bilateral cochlear implants (BiCIs) and their age-matched peers with normal hearing (NH).

DESIGN

All participants completed the Auditory Speech Sound Evaluation Phoneme Discrimination Test.

STUDY SAMPLE

The sample included 23 children with SeqBiCIs as the study group and 23 with NH as the control group.

RESULTS

A significant difference was found between the scores of the two groups under the CI₁ and CI₂ conditions (p = 0.001), CI₁ and BiCI conditions (p = 0.002), and CI₂ and BiCI conditions (p = 0.001). PD scores with CI₁ significantly depend on age at CI₁ and duration of bilateral use. PD scores with CI₁ were significant predictors of PD performance with CI₂. Duration of BiCI use was a significant predictor of PD scores with BiCI.

CONCLUSIONS

The age at CI₁ and the duration of bilateral cochlear implant use were found to improve phoneme discrimination performance in children with a sequential bilateral cochlear implant. According to the success of the CI₁, it is possible to predict the success of CI₂ use.

Bilateral Cochlear Implants or Bimodal Hearing for Children with Bilateral Sensorineural Hearing Loss

Purpose of review

This review describes speech perception and language outcomes for children using bimodal hearing (cochlear implant (CI) plus contralateral hearing aid) as compared to children with bilateral CIs and contrasts said findings with the adult literature. There is a lack of clinical evidence driving recommendations for bimodal versus bilateral CI candidacy and as such, clinicians are often unsure about when to recommend a second CI for children with residual acoustic hearing. Thus the goal of this review is to identify scientific information that may influence clinical decision making for pediatric CI candidates with residual acoustic hearing.

Recent findings

Bilateral CIs are considered standard of care for children with bilateral severe-to-profound sensorineural hearing loss. For children with aidable acoustic hearing-even in just the low frequencies-an early period of bimodal stimulation has been associated with significantly better speech perception, vocabulary, and language development. HA audibility, however, is generally poorer than that offered by a CI resulting in interaural asymmetry in speech perception, head shadow, as well as brainstem and cortical activity and development. Thus there is a need to optimize "two-eared" hearing while maximizing a child's potential with respect to hearing, speech, and language while ensuring that we limit asymmetrically driven auditory neuroplasticity. A recent large study of bimodal and bilateral CI users suggested that a period of bimodal stimulation was only beneficial for children with a better-ear pure tone average (PTA) ≤ 73 dB HL. This 73-dB-HL cutoff applied even to children who ultimately received bilateral CIs.

Summary

Though we do not yet have definitive guidelines for determining bimodal versus bilateral CI candidacy, there is increasing evidence that 1) bilateral CIs yield superior outcomes for children with bilateral severe-to-profound hearing loss and, 2) an early period of bimodal stimulation is beneficial for speech perception and language development, but only for children with better-ear PTA ≤ 73 dB HL. For children with residual acoustic hearing, even in just the low-frequency range, rapid sequential bilateral cochlear implantation following a trial period with bimodal stimulation will yield best outcomes for auditory, language, and academic development. Of course, there is also an increasing prevalence of cochlear implantation with acoustic hearing preservation allowing for combined electric and acoustic stimulation even following bilateral implantation.

Sequential Bilateral Cochlear Implantation With Prolonged Time Intervals

Purpose The aim of the study was to assess whether sequential cochlear implantation (CI) with a prolonged interimplant interval (M = 15.2 years) between the first and second CIs benefited speech recognition and health-related quality of life. Method This prospective study included 14 prelingually deafened participants who received their second CI after a prolonged interimplant interval (M = 15.2 years). Additionally, speech recognition ability over a 12-month period of bilateral implant use was investigated. The results of the speech recognition test in both quiet and noisy conditions were statistically analyzed for each CI alone and both CIs together. Nijmegen Cochlear Implant Questionnaire scores were also collected at activation and at 12 months after activation. Results Improvements in speech recognition ability were observed following the use of the first implant alone and with the use of both implants together; however, progress was much slower with the use of the second implant alone, following its introduction. Furthermore, a significant difference in the trajectory of speech recognition ability was observed between the first and the second implanted ear. According to Nijmegen Cochlear Implant Questionnaire scores, all participants benefitted from bilateral CI after 12 months. Conclusions Prolonged interimplant intervals resulted in asymmetrical speech recognition abilities. A significant improvement in the speech recognition scores was observed with the first implanted ear, and much slower progress was observed with the second implanted ear. However, the "poorer" second implanted ear could provide a considerable beneficial effect on the improved speech recognition and health-related quality of life with the bilateral CI. Supplemental Material https://doi.org/10.23641/asha.12861152.

The relationship of inter-implant time and hearing outcomes for bilateral cochlear implants

PURPOSE

Determine the relationship between time elapsed between sequential bilateral cochlear implantation (BiCI) and speech intelligibility scores in post-lingually deafened adults.

MATERIALS AND METHODS

Retrospective review of post-lingually deafened adults who received bilateral cochlear implants from January 1, 2011 to January 1, 2018 at an ambulatory tertiary referral center.

RESULTS

113 patients (226 cochlear implants) were initially reviewed, with 56 patients (112 implants) being included in the final analysis. Median inter-implant interval was 187.5 days (IQ range 54.25-346.5). Maximum interval was 1787 days. Mean age at first implant was 60.66 ± 13.37. Bilateral AzBio score in quiet and inter-implant interval showed no significant correlation (r = 0.034, p = 0.815). There was no significant difference in mean bilateral AzBio scores in quiet between the simultaneous and sequential implantation groups (p = 0.22). Similar non-significant results were seen when examining the correlation between AzBio Difference and inter-implant interval (r = -0.07, p = 0.66). No significant result between mean AzBio Difference of simultaneous and sequential implant recipients was found (p = 0.06).

CONCLUSIONS

For the inter-implant intervals examined, there seems to be no significant decline in speech intelligibility scores for patients receiving sequential bilateral cochlear implants compared to simultaneously implanted patients. There was no significant correlation noted between increasing inter-implant intervals and speech intelligibility scores.

Speech Perception Growth Patterns in Prelingual Deaf Children With Bilateral Sequential Cochlear Implantation

OBJECTIVE

To evaluate speech perception following the first (CI-1) and second (CI-2) cochlear implantation (CI) in children with sequential bilateral CI.

STUDY DESIGN

Retrospective.

PATIENTS

Seventy children with follow-up for 60 months post CI-1 and 36 months post CI-2.

MAIN OUTCOME MEASURES

Word recognition score (WRS) was the main outcome. WRSs were compared by age at CI operation (group A ≤ 3.5 yr, B 3.6-8.6, for CI-1; group I ≤ 3.5 yr, II 3.6-7.0, III 7.1-13, IV > 13, for CI-2).

RESULTS

For CI-1, the WRS of group A exceeded 80% at 24 months post procedure, earlier than group B (54 mo). Group A also had a shorter period of CI-1 use up to the WRS plateau than group B. CI-2 showed an initial burst of WRS growth much earlier than CI-1. This initial burst was most robust within 3 months in group II, but modest in group IV. The periods of CI-2 use (11-17 mo) up to the WRS plateau were much shorter than CI-1 (40-64 mo). Group I did not show the best WRS at 1 month post CI but later exceeded the other groups.

CONCLUSION

Children received an immediate benefit by a burst of WRS growth from CI-2 earlier than CI-1, even within 3 months, suggesting that CI-1 gets the auditory cortex ready to foster speech processing from CI-2. The CI-2 performance depends on age at CI-2 implantation and on CI-1 performance. Our current findings will be relevant for clinicians who are counselling parents on CI-2 surgery.

Categories of Auditory Performance and Speech Intelligibility Ratings in Prelingually Deaf Children With Bilateral Implantation

Purpose The aim of the current study was to review all pediatric cases with congenital deafness who underwent bilateral implantation in our center. Specifically, auditory performance and speech intelligibility ratings were compared across children based on their mode of bilateral stimulation (simultaneous or sequential implantation). Method A retrospective chart review design was used in this study. A total of 46 congenitally deaf children were included. Children ranged in age between 2 and 8 years, with a mean of 3 years 7 months. Participants were divided into 2 groups: those who received their bilateral implant simultaneously and those who received them sequentially. Categories of Auditory Performance (CAP; Archbold, Lutman, & Marshall, 1995 ) scores and Speech Intelligibility Rating (SIR; M. C. Allen, Nikolopoulos, & O'Donoghue, 1998 ) scores were used to measure their performance. Results Children scored an average of 4.1 (±1.6) on the CAP Scale and 1.6 (±1) on the SIR Scale. Results showed that children who received their implants simultaneously scored relatively higher on the CAP Scale than those with sequential implants. However, there were no differences between the 2 groups in SIR scores. These 2 outcome measures were not correlated with age at implantation. Conclusion The current study demonstrated that simultaneous implantation could potentially improve audiologic outcome.

Sequential pediatric bilateral cochlear implantation: The effect of time interval between implants

OBJECTIVE

To examine speech intelligibility in children subjected to sequential bilateral cochlear implants (CI) surgery and to assess the influence of the inter-stage interval duration.

INTRODUCTION

Binaural hearing recovery can have additional benefits, especially in speech and language development in patients with congenital profound sensorineural hearing loss; so recently there has been an increase in the number of children receiving bilateral CI.

METHODS

Twenty-seven children who underwent sequential bilateral cochlear implant (SBCI) with a short (1-3 yrs), medium (4-6 yrs) and long (7-12 yrs) range interval between both implantations, respectively, were evaluated. All patients underwent periodic speech perception test in quiet and noise after second implant activation in three conditions: with the first or second implant alone and with both implants. Results were examined according to the inter-stage interval.

RESULTS

Speech intelligibility in noise was significantly better under bilateral conditions than either ear alone, in all three groups. Small improvements were seen in quiet, especially in the third group (6-12 yrs).

CONCLUSION

Benefits of second implant in the early-implanted children and after a short inter-implant delay are more evident. However our study support that, even after a long period of deafness and despite a prolonged inter-stage interval, sequential bilateral cochlear implantation should be considered.

LEVEL OF EVIDENCE

Level 4.

Speech recognition in bilaterally cochlear implanted adults in Tokyo, Japan

INTRODUCTION

The clinical effects of bilateral cochlear implantation (BCI) include binaural summation and better hearing under noise conditions. This study retrospectively examined the utility of BCI compared to unilateral cochlear implantation (CI) in adults.

PATIENTS AND METHODS

We investigated 34 adults who underwent BCI, comparing speech recognition between BCI and first CI under silent and noise conditions. We assessed correlations between speech recognition after first and second CIs, and between the interval from first to second CI surgery and speech recognition of second CI.

RESULTS

Word recognition score (WRS) and sentence recognition score (SRS) were significantly better after BCI than after first CI under conditions of silence and noise. No significant correlation was found between speech recognition after first CI and that after second CI, or between inter-implant interval and speech recognition of second CI for either WRS or SRS.

CONCLUSIONS

The utility of BCI in Japanese patients was shown. Patients have no need to be pessimistic about hearing after the second implantation even if speech recognition after the first implantation is poor. A long interval from first CI does not necessarily contraindicate contralateral implantation in adults.

A Longitudinal Study in Children With Sequential Bilateral Cochlear Implants: Time Course for the Second Implanted Ear and Bilateral Performance

PURPOSE

Whether, and if so when, a second-ear cochlear implant should be provided to older, unilaterally implanted children is an ongoing clinical question. This study evaluated rate of speech recognition progress for the second implanted ear and with bilateral cochlear implants in older sequentially implanted children and evaluated localization abilities.

METHOD

A prospective longitudinal study included 24 bilaterally implanted children (mean ear surgeries at 5.11 and 14.25 years). Test intervals were every 3-6 months through 24 months postbilateral. Test conditions were each ear and bilaterally for speech recognition and localization.

RESULTS

Overall, the rate of progress for the second implanted ear was gradual. Improvements in quiet continued through the second year of bilateral use. Improvements in noise were more modest and leveled off during the second year. On all measures, results from the second ear were poorer than the first. Bilateral scores were better than either ear alone for all measures except sentences in quiet and localization.

CONCLUSIONS

Older sequentially implanted children with several years between surgeries may obtain speech understanding in the second implanted ear; however, performance may be limited and rate of progress gradual. Continued contralateral ear hearing aid use and reduced time between surgeries may enhance outcomes.

United Kingdom national paediatric bilateral project: Demographics and results of localization and speech perception testing

OBJECTIVES

To assess longitudinal outcomes in a large and varied population of children receiving bilateral cochlear implants both simultaneously and sequentially.

METHODS

This observational non-randomized service evaluation collected localization and speech recognition in noise data from simultaneously and sequentially implanted children at four time points: before bilateral cochlear implants or before the sequential implant, 1 year, 2 years, and 3 years after bilateral implants. No inclusion criteria were applied, so children with additional difficulties, cochleovestibular anomalies, varying educational placements, 23 different home languages, a full range of outcomes and varying device use were included.

RESULTS

1001 children were included: 465 implanted simultaneously and 536 sequentially, representing just over 50% of children receiving bilateral implants in the UK in this period. In simultaneously implanted children the median age at implant was 2.1 years; 7% were implanted at less than 1 year of age. In sequentially implanted children the interval between implants ranged from 0.1 to 14.5 years. Children with simultaneous bilateral implants localized better than those with one implant. On average children receiving a second (sequential) cochlear implant showed improvement in localization and listening in background noise after 1 year of bilateral listening. The interval between sequential implants had no effect on localization improvement although a smaller interval gave more improvement in speech recognition in noise. Children with sequential implants on average were able to use their second device to obtain spatial release from masking after 2 years of bilateral listening. Although ranges were large, bilateral cochlear implants on average offered an improvement in localization and speech perception in noise over unilateral implants.

CONCLUSION

These data represent the diverse population of children with bilateral cochlear implants in the UK from 2010 to 2012. Predictions of outcomes for individual patients are not possible from these data. However, there are no indications to preclude children with long inter-implant interval having the chance of a second cochlear implant.

Asymmetric Hearing During Development: The Aural Preference Syndrome and Treatment Options

Deafness affects ∼2 in 1000 children and is one of the most common congenital impairments. Permanent hearing loss can be treated by fitting hearing aids. More severe to profound deafness is an indication for cochlear implantation. Although newborn hearing screening programs have increased the identification of asymmetric hearing loss, parents and caregivers of children with single-sided deafness are often hesitant to pursue therapy for the deaf ear. Delayed intervention has consequences for recovery of hearing. It has long been reported that asymmetric hearing loss/single-sided deafness compromises speech and language development and educational outcomes in children. Recent studies in animal models of deafness and in children consistently show evidence of an "aural preference syndrome" in which single-sided deafness in early childhood reorganizes the developing auditory pathways toward the hearing ear, with weaker central representation of the deaf ear. Delayed therapy consequently compromises benefit for the deaf ear, with slow rates of improvement measured over time. Therefore, asymmetric hearing needs early identification and intervention. Providing early effective stimulation in both ears through appropriate fitting of auditory prostheses, including hearing aids and cochlear implants, within a sensitive period in development has a cardinal role for securing the function of the impaired ear and for restoring binaural/spatial hearing. The impacts of asymmetric hearing loss on the developing auditory system and on spoken language development have often been underestimated. Thus, the traditional minimalist approach to clinical management aimed at 1 functional ear should be modified on the basis of current evidence.

Clinical and logopaedic results of simultaneous and sequential bilateral implants in children with severe and/or profound bilateral sensorineural hearing loss: A literature review

This article carries out a literature review of the advantages and limitations of the simultaneous bilateral cochlear implantation (SCI) compared to those of the sequential bilateral cochlear implantation (SBCI) and the unilateral cochlear implantation (UCI). The variables analysed in said comparison are: safety and surgical technique, SCI incidence, effectiveness, impact of the inter-implant interval, costs and financing, impact on brain plasticity, impact on speech and language development, main benefits, main disadvantages and concerns, and predictive factors of prognosis. Although the results are not conclusive, all variables analysed seem to point towards observable benefits of SCI in comparison with SBCI or UCI. This tendency should be studied in more depth in multicentre studies with higher methodological rigour, more comprehensive samples and periods and other determining variables (age at the time of implantation, duration and degree of the hearing loss, rehabilitation methodologies used, family involvement, etc.).

Are Young Children With Cochlear Implants Sensitive to the Statistics of Words in the Ambient Spoken Language?

PURPOSE

The purpose of this study was to determine whether children with cochlear implants (CIs) are sensitive to statistical characteristics of words in the ambient spoken language, whether that sensitivity changes in expected ways as their spoken lexicon grows, and whether that sensitivity varies with unilateral or bilateral implantation.

METHOD

We analyzed archival data collected from the parents of 36 children who received cochlear implantation (20 unilateral, 16 bilateral) before 24 months of age. The parents reported their children's word productions 12 months after implantation using the MacArthur Communicative Development Inventories: Words and Sentences (Fenson et al., 1993). We computed the number of words, out of 292 possible monosyllabic nouns, verbs, and adjectives, that each child was reported to say and calculated the average phonotactic probability, neighborhood density, and word frequency of the reported words.

RESULTS

Spoken vocabulary size positively correlated with average phonotactic probability and negatively correlated with average neighborhood density, but only in children with bilateral CIs.

CONCLUSION

At 12 months postimplantation, children with bilateral CIs demonstrate sensitivity to statistical characteristics of words in the ambient spoken language akin to that reported for children with normal hearing during the early stages of lexical development. Children with unilateral CIs do not.

Cochlear implantation: a biomechanical prosthesis for hearing loss

Cochlear implants are a medical prosthesis used to treat sensorineural deafness, and one of the greatest advances in modern medicine. The following article is an overview of cochlear implant technology. The history of cochlear implantation and the development of modern implant technology will be discussed, as well as current surgical techniques. Research regarding expansion of candidacy, hearing preservation cochlear implantation, and implantation for unilateral deafness are described. Lastly, innovative technology is discussed, including the hybrid cochlear implant and the totally implantable cochlear implant.

The influence of newborn hearing screening on the age at cochlear implantation in children

OBJECTIVES/HYPOTHESIS

To evaluate the influence of the introduction of newborn hearing screening programs on the age at cochlear implantation in children.

STUDY DESIGN

Retrospective, multicenter cohort study.

METHODS

All 1,299 pediatric cochlear implant users who received their implants before the age of 5 years between 1995 and 2011 in the Medical University Hannover, Germany and University Medical Center Utrecht, the Netherlands were enrolled in this study. Age at implantation and the number of children implanted within the first year of life was assessed for each center.

RESULTS

Age at cochlear implantation gradually declined over the years in both centers. The introduction of the screening resulted in significant decline in the age at implantation in the Netherlands; simultaneously, the number of children implanted within their first year of life increased significantly. Comparing 4-year epochs immediately before and after introduction of the screening, the mean age decreased from 2.4 to 1.2 years, and the percentage of early implanted children increased from 9% to 37%. In the German population, a similar effect of the introduction of the hearing screening program was absent.

CONCLUSIONS

The introduction of the national newborn hearing screening program has reduced the age at cochlear implantation in young children in the Netherlands but not in Germany. Correspondingly, it resulted in an increase in the number of children implanted early in life. The difference between the Dutch and German population might be due to differences in the follow-up and referral after the hearing screening.