Cochlear implants in children--a review

Efficacy of auditory verbal therapy in children with cochlear implantation based on auditory performance - A systematic review

This systematic review focuses on the efficacy of auditory verbal therapy (AVT) in children with cochlear implants based on their auditory performance. The results presented are based on research findings from 2010 to 2021. The systematic review was designed based on the Popular Reporting Systems for the Systematic Review and Analysis of Meta-Analysts (PRISMA), the 2020 revised version, and the Critical Evidence for Clinical Evidence (CATE) checklist. Specific keywords were chosen based on the formulated research question and searched on the following search engines: Google Scholar, Microsoft Academic, PubMed, Semantic Scholar, Cochrane, Science Direct, and BASE. All the searched articles were analysed based on specific exclusion criteria. The results revealed an important progression based on the auditory performance among children with cochlear implantation who received habilitation. The studies highlight that younger the age at implantation better the auditory performance and this may be necessary to allow at least relatively normal organization of auditory pathways in pre-lingual children with hearing impairment. Therefore, regular revitalization of aural-verbal rehabilitation and speech and language therapy is essential for younger children with hearing impairment to achieve the highest level of hearing function. This systematic review highlights importance of assessment of the auditory performance to be considered in the test battery while evaluating children with CI before and after habilitation along with AVT.

Institutional Analysis of the Surgical Outcomes of Cochlear Implantation in Deprived Population

BACKGROUND

Cochlear implantation (CI) surgeries are safe and performed successfully in many patients; however, postoperative complications still occur, which may be influenced by socioeconomic and demographic variables.  Methodology: This is a retrospective observational study of 146 adults and children with hearing loss, who had CI surgery between 2017 and 2022. This study aims to assess the frequency and nature of surgical complications in patients from a low socioeconomic background who underwent CI surgery in different geographic areas. For the analysis of data, IBM SPSS Statistics for Windows, Version 21.0 (Released 2012; IBM Corp., Armonk, New York, United States) was used.

RESULT

A total of 146 candidates were evaluated, out of which 82 were male (56.16%) and 64 (43.84%) were female. The age of patients at the time of surgery ranged from 1-50 years. All of the patients underwent unilateral CI. Eighteen implanted patients developed minor complications with an incidence rate of 12.31%. There were no major complications observed. Further, we did not observe any post-operative meningitis as our study group was vaccinated against pneumococcal and meningococcal diseases and Haemophilus influenzae type B (Hib).

CONCLUSION

CI is an effective and safe surgical procedure for the treatment and rehabilitation of people who are deaf. It is possible to avoid complications by using meticulous surgical methods and regular post-operative monitoring to identify and treat any issues as soon as possible, regardless of socioeconomic status.

Cochlear Implant Complications in Children and Adults: Retrospective Analysis of 148 Cases

Objective

This study aimed to establish and discuss the intraoperative and postoperative complications affecting patients who underwent cochlear implant (CI) surgery from the Cochlear Implant Program of King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia.

Methods

A retrospective study was conducted by reviewing the medical records of 148 patients who underwent cochlear implantation at KAUH between 1999 and 2019. Postoperative complications were classified into minor and major complications. Minor complications resolved with minimal or no treatment. Major complications required additional surgery or hospitalization.

Results

Complications occurred in 28 (18.9%) patients. Minor complications occurred in 17 (11.5%) patients, which included otitis media (2%), facial palsy (1.4%), wound infection (1.4%), vertigo (1.4%), intraoperative cerebrospinal fluid (CSF) gusher (1.4%), tinnitus (1.4%), facial stimulation (1.4%), hematoma (0.7%), and chorda tympani nerve injury (0.7%). Major complications occurred in 11 (7.4%) patients. These included flap dehiscence/infection (2%), device failure (1.4%), device migration (1.4%), mastoiditis (1.4%), electrode damage during insertion (0.7%), and misplaced electrodes (0.7%).

Conclusion

This study reported a low rate of surgical complications associated with CI, and most have been managed successfully without further complications. Our results prove that CI is a safe and reliable procedure, with a low complications rate when performed by experienced surgeons.

Cochlear implant outcomes in children with attention-deficit/hyperactivity disorder: Comparison with controls

OBJECTIVES

The coincidence of attention-deficit/hyperactivity disorder (ADHD) and hearing loss in the children has adverse effects in speech, cognition, communication and motor development. This can influence cochlear implant (CI) outcomes negatively. The aim of this study was to compare auditory, language, speech, cognition, communication and motor outcomes between CI children with versus without ADHD.

METHODS

Nineteen CI children with ADHD and twenty-three age and gender matched children without ADHD at the Shiraz CI center ranging in age from 37 to 60 months were participated in this cross-sectional study. The developmental quotient in auditory, receptive and expressive language, speech and cognition skills was evaluated through Newsha Developmental Scale. The Persian version of the Ages and Stages Questionnaire (ASQ) was used to assess children's developmental status in fine and gross movements, communication, problem solving, and personal-social domains. A comparison of the results between two groups was made by the Mann-Whitney test.

RESULTS

CI children with ADHD had significantly lower Newsha developmental quotients in cases of auditory, receptive and expressive language, speech and cognition skills compared to the control group (P = 0.027 to <0.001). A significant difference was observed between children with and without ADHD in fine and gross movements, communication, problem solving, and personal-social domains of ASQ at 60 months (P = 0.029 to 0.003).

CONCLUSION

Children with ADHD showed decreased ability in auditory, language, speech, cognition, motor and communication skills following CI compared to children without ADHD. It can guide clinician to provide these children with more specific rehabilitation program to improve their skills.

Corrosion performance of cold deformed austenitic stainless steels for biomedical applications

Austenitic stainless steels possess an excellent balance of strength and ductility along with the high ability to further raise their strength during cold deformation (CD). Corrosion resistance of austenitic stainless steels (SSs) is affected by cold deformation because passive films on the surface of steels are expected to be modified. A low level of CD enhances the surface diffusion, which results in the formation of a stable passive film leading to an increase in the corrosion resistance in neutral chloride solutions. The chromium content in the passive film on a deformed steel surface is usually richer, with a higher Cr/Fe ratio than that formed on annealed steels. A higher chromium content makes surface films more stable, which improves the corrosion resistance. However, severe CD results in the formation of strain-induced martensite phase and deformation twins, which decreases the localized corrosion resistance by increasing the number of active anodic sites on the surface. The corrosion resistance, especially the pitting resistance, in SSs is diminished with increasing volume fraction of the martensite. In this review, we highlighted the failure modes of corrosion of stainless steel implants, factors affecting corrosion, and effect of CD on mechanical properties and emphatically on the corrosion resistance of SSs for biomedical applications.

Duration of unilateral auditory deprivation is associated with reduced speech perception after cochlear implantation: A single-sided deafness study

OBJECTIVE

Examine the relationship between duration of unilateral deafness and speech perception outcomes after cochlear implantation in adults with single-sided deafness.

METHODS

A systematic review of PubMed articles containing individual speech perception and duration of deafness data from single-sided deaf adults. Studies were selected for detailed review and duration of deafness and speech perception outcomes were extracted, with speech scores reported as percent correct. A linear regression as a function of study and length of deafness was performed.

RESULTS

A statistically significant negative effect of duration of unilateral deafness on speech perception was found, but there was substantial uncertainty regarding the strength of the effect.

DISCUSSION

Existing data make it difficult to either support or reject a hard 5- or 10-year unilateral auditory deprivation limit on cochlear implant (CI) candidacy for patients with single-sided deafness. This is because the totality of available data are consistent with a very small effect, perhaps negligible in practical terms, and just as consistent with a very large effect. Regardless of effect size, the present results have important basic implications. They suggest that unilateral sound deprivation may have a deleterious effect on auditory processing even though more central parts of the auditory system have continued to receive input from a contralateral normal ear.

CONCLUSIONS

Speech perception scores in SSD patients are negatively correlated with duration of deafness, but the limited amount of data from cochlear implant users with long-term single-sided deafness leads to substantial uncertainly, which in turn precludes any strong clinical recommendations. Further study of SSD CI users with long-term deafness will be necessary to generate evidence-based guidelines for implantation criteria in this population.

Outcomes of cochlear implantation in children with and without inner ear malformations

Objective:

To evaluate the auditory functions and progress of speech development in children with and without cochlear anomalies who underwent cochlear implantation due to prelingual profound sensorineural hearing loss (SNHL).

Methods:

This study was conducted at Gaziantep University Faculty of Medicine Ear-Nose-Throat Department, between October 2006 and December 2007. A total of 69 children (aged 6 to 24 months) diagnosed with profound SNHL were included. Patients were divided into two groups with respect to the presence of inner ear anomalies: Group-1 consisted of 41 children without inner ear anomaly, whereas Group-2 was composed of 28 patients with inner ear anomalies. The auditory performance was assessed using Listening Progress Profile Test (LPPT) and Monosyllabic Trochee Polysyllabic Test (MTP), the subsections of Evaluation of Auditory Responses to Speech (EARS) test battery.

Results:

Preoperative LPPT scores were 5 (12%) in both groups. Mean LPPT values after fitting in Group-1 and Group-2 on 1^st, 3^rd and 6^th months were 18.5 (44.1%) and 19 (45.6%); 27 (64.2%) and 28 (67.3%); 31 (75%) and 34 (83%), respectively. Postoperatively, MTP scores in Group-1 and Group-2 were 7.5 (62%) and 7.7 (64%) for 3-words set; 10.4 (58%) and 10.6 (59%) for 6-words set; 14.3 (60%) and 14 (59%) for 12-words set, respectively. The rate of stimulation for electrodes was 1345 q/u (quick/unit) in Group-1 and 1310 q/u in Group-2. No statistically significant difference was detected between groups for variables under investigation.

Conclusion:

Cochlear implantation is an effective treatment in children with prelingual profound SNHL. Auditory performance and advancement of speech are similar for children with and without inner ear anomalies.

Cost-Effectiveness of Pediatric Cochlear Implantation in Rural China

Objectives:

To evaluate the cost utility of cochlear implantation (CI) for severe to profound sensorineural hearing loss (SNHL) among children from rural settings in P.R. China (China).

Research Design:

A cost-utility analysis (CUA) was undertaken using data generated from a single-center substudy of the Cochlear^TM Pediatric Implanted Recipient Observational Study (Cochlear P-IROS). The data were projected over a 20-year time horizon using a decision tree model.

Setting:

The Chinese healthcare payer and patient perspectives were adopted.

Intervention:

Unilateral CI of children with a severe-to-profound SNHL compared with their preimplantation state of no treatment or amplification with hearing aids (“no CI” status).

Main Outcome Measure/s:

Incremental costs per quality adjusted life year (QALY) gained.

Results:

The mean total discounted cost of unilateral CI was CNY 252,506 (37,876 USD), compared with CNY 29,005 (4,351 USD) for the no CI status from the healthcare payer plus patient perspective. A total discounted benefit of 8.9 QALYs was estimated for CI recipients compared with 6.7 QALYs for the no CI status. From the healthcare payer plus patient perspective, incremental cost-effectiveness ratio (ICER) for unilateral CI compared with no CI was CNY 100,561 (15,084 USD) per QALY. The healthcare payer perspective yielded an ICER of CNY 40,929 (6,139 USD) per QALY. Both ICERs fell within one to three times China's gross domestic product per capita (GDP, 2011–2015), considered “cost-effective” by World Health Organization (WHO) standards.

Conclusions:

Treatment with unilateral CI is a cost-effective hearing solution for children with severe to profound SNHL in rural China. Increased access to mainstream education and greater opportunities for employment, are potential downstream benefits of CI that may yield further societal and economic benefits. CI may be considered favorably for broader inclusion in medical insurance schemes across China.

Technical challenges and safety of magnetic resonance imaging with in situ neuromodulation from spine to brain

PURPOSE

This review summarises the need for MRI with in situ neuromodulation, the key safety challenges and how they may be mitigated, and surveys the current status of MRI safety for the main categories of neuro-stimulation device, including deep brain stimulation, vagus nerve stimulation, sacral neuromodulation, spinal cord stimulation systems, and cochlear implants.

REVIEW SUMMARY

When neuro-stimulator systems are introduced into the MRI environment a number of hazards arise with potential for patient harm, in particular the risk of thermal injury due to MRI-induced heating. For many devices however, safe MRI conditions can be determined, and MRI safely performed, albeit with possible compromise in anatomical coverage, image quality or extended acquisition time.

CONCLUSIONS

The increasing availability of devices conditional for 3 T MRI, whole-body transmit imaging, and imaging in the on-stimulation condition, will be of significant benefit to the growing population of patients benefitting from neuromodulation therapy, and open up new opportunities for functional imaging research.

Cochlear implantation in Pendred syndrome and non-syndromic enlarged vestibular aqueduct - clinical challenges, surgical results, and complications

OBJECTIVE

To explore specific clinical issues, surgical results, and complications of 80 cochlear implantations (CI) in 55 patients with Pendred syndrome (PS) or non-syndromic enlarged vestibular aqueduct (NSEVA).

BACKGROUND

Previous studies have focused either on unselected case series or on populations with mixed cochlear malformations. PS/NSEVA accounts for up to 10% of congenital SNHL, rendering this a large group of cochlear implant candidates. The abnormal inner ear anatomy of these patients may be associated with a lower surgical success rate and a higher rate of complications.

STUDY DESIGN

Retrospective review of patients' medical records and CT/MRI.

SETTING

Tertiary referral center.

MATERIALS AND METHODS

The medical records and CT/MRI images of 55 PS/NSEVA patients receiving 80 cochlear implantations from 1982-2014 were reviewed. Demographic data, surgical results, intra-operative incidents, and post-operative complications were retrieved.

RESULTS

Complications occurred in 36% of implantations; 5% hereof major complications. Gushing/oozing from the cochleostoma occurred in 10% of implantations and was related to transient, but not prolonged post-operative vertigo.

CONCLUSION

Intra-operative risks of gushing/oozing and post-operative vertigo are the primary clinical issues in PS/NSEVA patients regarding CI. Nonetheless, the surgical success rate is high and the major complication rate is low; similar to studies of unselected series of CI recipients.

Nucleus Freedom North American Clinical Trial

OBJECTIVE: To evaluate hearing outcomes and effects of stimulation rate on performance with the Nucleus Freedom cochlear implant (Cochlear Americas, Denver, CO).

STUDY DESIGN AND SETTING: Randomized, controlled, prospective, single-blind clinical study using single-subject repeated measures (A-B-A-B) design at 14 academic centers in the United States and Canada and comparison with outcomes of a prior device by the same manufacturer.

PATIENTS: Seventy-one severely/profoundly hearing impaired adults.

RESULTS: Seventy-one adult recipients were randomly programmed in two different sets of rate: ACE or higher rate ACE RE. Mean scores for Consonant Nucleus Consonant words is 57%, Hearing in Noise Test (HINT) sentences in quiet 78%, and HINT sentences in noise 64%. Sixty-seven percent of subjects preferred slower rates of stimulation, and performance did not improve with higher rates of stimulation using this device.

CONCLUSIONS: Subjects performed well, and there was no advantage to higher stimulation rates with this device.

SIGNIFICANCE: Higher stimulation rates do not necessarily result in improved performance.

One-year experience with the Cochlear™ Paediatric Implanted Recipient Observational Study (Cochlear P-IROS) in New Delhi, India

Background

Currently, there is a significant lack of data concerning long-term outcomes following paediatric cochlear implantation in terms of quality of life. There is a need for a long-term, prospective study in this regard. This study aims at highlighting the preliminary results, one year post surgery of a five year prospective study.

Methods

The Cochlear™ Paediatric Implanted Recipient Observational Study (P-IROS) is a prospective, patient outcomes registry for routinely implanted children. The study collects data using questionnaires post-surgery and at regular intervals up to five years.

Results

At our Centre, 159 cochlear implant surgery procedures were carried out between January 2014 and December 2014. Category of Auditory Performance II score increased from ‘0’ to ‘3’ at six months and to ‘5’ at 12 months for children aged 0–3 years, although this was not statistically significant. However, the same trend was statistically significant for the age 3–6 year and age 6–10 year brackets. The quality of life of the child improved significantly. Analysis of communication mode revealed a statistically significant overall shift to the auditory-oral mode from total communication.

Conclusion

Cochlear implantation is a life-changing intervention. The evidence in support of what it can achieve safely is clear. However, the costs associated with it raise the question if it will remain an effective option for life in all children. The Cochlear P-IROS is an attempt to answer the same over a five year period. Our study in New Delhi, so far concludes that cochlear implantation in a population with limited access to funds is very effective, one year after surgery.

A global patient outcomes registry: Cochlear paediatric implanted recipient observational study (Cochlear(™) P-IROS)

BACKGROUND

Currently, there is a paucity of data concerning the long-term outcomes, educational placement and quality of life of children implanted with hearing devices from large and representative samples of the population. To address this concern, a large, prospective, multicentre, multinational patient-outcomes registry for paediatric recipients of implantable hearing devices was developed. The benefits of this registry, its approach and methodology are described.

METHODS/DESIGN

The Cochlear(™) Paediatric Implanted Recipient Observational Study (Cochlear P-IROS) is a prospective international patient-outcomes registry for children who are implanted in routine clinical practice with one or more hearing devices. The study aims to collect data on patient comorbidities, device use, auditory performance, quality of life and health-related utilities, across different types of implantable hearing devices from a range of manufacturers. Patients will be evaluated with a set of standardised and non-standardised questionnaires prior to initial device activation (baseline) and at six-monthly follow-up intervals up to 24 months and annually thereafter. The Cochlear P-IROS utilises a secure web interface to administer electronic case report forms to clinicians and families of implanted children. The web interface is currently available in five languages: English, Japanese, Korean, Mandarin and Russian. The interface also provides printable versions of the case report forms translated into 22 local languages for collection of data prior to entry online; additional languages may be added, as required. Participation in the Cochlear P-IROS registry is investigator-driven and voluntary. To date, the Cochlear P-IROS has recruited implant clinics across Australia, China, India, Indonesia, Turkey and Vietnam. The registry also aims to recruit multiple clinics in Cuba, Israel, Japan, Malaysia, Singapore, South Africa, South Korea and Russia.

DISCUSSION

The use of a registry such as the Cochlear P-IROS will generate valuable data to support research interests of academics and clinicians around the globe. The data generated will be relevant for a wide range of stakeholders including regulators, payers, providers, policy makers, patients and their families, each with a different perspective for the acceptance and adoption of implantable hearing devices for the treatment of hearing loss.

A surgical navigation system for guiding exact cochleostomy using auditory feedback: a clinical feasibility study

In cochlear implantation (CI), the insertion of the electrode array into the appropriate compartment of the cochlea, the scala tympani, is important for an optimal hearing outcome. The current surgical technique for CI depends primarily on the surgeon's skills and experience level to achieve the correct placement of the electrode array, and the surgeon needs to confirm that the exact placement is achieved prior to completing the procedure. Thus, a surgical navigation system can help the surgeon to access the scala tympani without injuring important organs in the complex structure of the temporal bone. However, the use of a surgical microscope has restricted the effectiveness of the surgical navigation because it has been difficult to deliver the navigational information to the surgeon from outside of the surgeon's visual attention. We herein present a clinical feasibility study of an auditory feedback function developed as a computer-surgeon interface that can guide the surgeon to the preset cochleostomy location. As a result, the surgeon could confirm that the drilling point was correct, while keeping his or her eyes focused on the microscope. The proposed interface reduced the common frustration that surgeons experience when using surgical navigation during otologic surgeries.

Semantic organization in children with cochlear implants: computational analysis of verbal fluency

PURPOSE

Cochlear implants (CIs) enable children with severe and profound hearing impairments to perceive the sensation of sound sufficiently to permit oral language acquisition. So far, studies have focused mainly on technological improvements and general outcomes of implantation for speech perception and spoken language development. This study quantitatively explored the organization of the semantic networks of children with CIs in comparison to those of age-matched normal hearing (NH) peers.

METHOD

Twenty seven children with CIs and twenty seven age- and IQ-matched NH children ages 7-10 were tested on a timed animal verbal fluency task (Name as many animals as you can). The responses were analyzed using correlation and network methodologies. The structure of the animal category semantic network for both groups were extracted and compared.

RESULTS

Children with CIs appeared to have a less-developed semantic network structure compared to age-matched NH peers. The average shortest path length (ASPL) and the network diameter measures were larger for the NH group compared to the CIs group. This difference was consistent for the analysis of networks derived from animal names generated by each group [sample-matched correlation networks (SMCN)] and for the networks derived from the common animal names generated by both groups [word-matched correlation networks (WMCN)].

CONCLUSIONS

The main difference between the semantic networks of children with CIs and NH lies in the network structure. The semantic network of children with CIs is under-developed compared to the semantic network of the age-matched NH children. We discuss the practical and clinical implications of our findings.

Cochlear implantation for a child with cochlear nerve deficiency: parental perspectives explored through narrative

OBJECTIVE

The objective of this study was to explore, from the parents' perspectives, decision-making regarding a cochlear implant (CI) for their child when a favourable outcome is less likely because of abnormal neurophysiology.

DESIGN

The primary research method of this single case study was qualitative interviewing drawing on a narrative approach to elicit the parents' perspectives about their experiences over time. Each parent was interviewed separately, but thematic analyses were undertaken both within and across interviews in order to identify overlaps and differences.

STUDY SAMPLE

Participants included the parents of a five-year old child with severe-profound hearing loss, cochlear nerve deficiency, and bilateral common cavities who had received a CI at the age of 18 months.

RESULTS

Four themes were identified across the four narrative stages that emerged from the parents' accounts of their experiences regarding their daughter's CI. Themes included hope and despair, questioning professionals' motivations, does deafness need a cure, and bringing the child into the family. Although these themes emerged from both parents' accounts, each parent expressed different perspectives and insights within them.

CONCLUSIONS

Findings highlight the central place of parental needs and perspectives in decision-making regarding a CI, particularly in the context of uncertain outcomes.

Speech through ears and eyes: interfacing the senses with the supramodal brain

The comprehension of auditory-visual (AV) speech integration has greatly benefited from recent advances in neurosciences and multisensory research. AV speech integration raises numerous questions relevant to the computational rules needed for binding information (within and across sensory modalities), the representational format in which speech information is encoded in the brain (e.g., auditory vs. articulatory), or how AV speech ultimately interfaces with the linguistic system. The following non-exhaustive review provides a set of empirical findings and theoretical questions that have fed the original proposal for predictive coding in AV speech processing. More recently, predictive coding has pervaded many fields of inquiries and positively reinforced the need to refine the notion of internal models in the brain together with their implications for the interpretation of neural activity recorded with various neuroimaging techniques. However, it is argued here that the strength of predictive coding frameworks reside in the specificity of the generative internal models not in their generality; specifically, internal models come with a set of rules applied on particular representational formats themselves depending on the levels and the network structure at which predictive operations occur. As such, predictive coding in AV speech owes to specify the level(s) and the kinds of internal predictions that are necessary to account for the perceptual benefits or illusions observed in the field. Among those specifications, the actual content of a prediction comes first and foremost, followed by the representational granularity of that prediction in time. This review specifically presents a focused discussion on these issues.

Auditory and speech performance in deaf children with deaf parents after cochlear implant

OBJECTIVE

To evaluate the auditory and speech outcome in deaf children with deaf parents (CDP) after cochlear implantation (CI), emphasizing both the presence of additional caregiver and patients' main communication mode.

STUDY DESIGN

Retrospective case review.

SETTING

Cochlear implant center at a tertiary referral hospital.

PATIENTS

Fourteen CDP and 14 age- and sex-matched deaf children with normal-hearing parents (CNH).

MAIN OUTCOME MEASURE(S)

The Korean version of Ling's stage (K-Ling) and Category of Auditory Perception (CAP) were administered to the children to assess the speech production and auditory perception abilities, preoperatively and 3, 6, 12, and 24 months after CI. To elucidate the effects of the additional caregiver and main communication mode of the implanted child, the patients were divided into the following groups: with additional caregiver(s) who have normal hearing (n = 11) versus without additional caregiver (n = 3); sign language plus oral communication (S+O) group (n = 9) versus oral communication only (O) group (n = 5).

RESULTS

CAP scores and K-Ling stages improved remarkably in both CDP and CNH, and no significant differences were found between the 2 groups. Within the CDP group, CAP scores and K-Ling stages improved significantly in CDP with an additional caregiver than those without. Auditory perception and speech production performances in the S+O group were similar to those in the O group.

CONCLUSION

CDP can develop similarly to CNH in auditory perception and speech production, if an additional caregiver with normal hearing provides sufficient support and speech input. In addition, using sign language in addition to oral language might not be harmful, and these children can be a communication bridge between their deaf parents and society.

Long term speech perception after cochlear implant in pediatric patients with GJB2 mutations

OBJECTIVES

To determine the long term effect of cochlear implant (CI) in children with GJB2-related deafness in Japan.

METHODS

Genetic testing was performed on 29 children with CI. The speech perception in 9 children with GJB2 gene-related deafness fitted with CI was compared with those in matched 10 children who were diagnosed as having no genetic loci. The average follow-up period after CI was 55.9 months and 54.6 months, respectively.

RESULTS

A definitive inherited hearing impairment could be confirmed in 12 (41.4%) of the 29 CI children, including 10 with GJB2-related hearing impairment and 2 with SLC26A4-related hearing impairment. The results of IT-MAIS, word or speech perception testing under the noise, and development of speech perception and production testing using the Enjoji scale were slightly better for the GJB2 group after CI than for the control group without statistical significant difference.

CONCLUSION

The long-term results of this study show that CI is also effective in the development of speech performance after CI in Japanese children with GJB2-related hearing impairments as HL due to other etiologies.

Observation of cortical activity during speech stimulation in prelingually deafened adults with cochlear implantation by positron emission tomography-computed tomography

OBJECTIVES

We evaluated the cortical activity of 2 successful prelingually deafened adult cochlear implant (CI) users who have been trained by auditory-verbal/oral communication since childhood.

METHODS

Changes in regional cerebral blood flow were measured by positron emission tomography using '8F-fluorodeoxyglucose while the subjects were receiving auditory language stimuli by listening to a story. Ten normal-hearing volunteers were observed as age-matched control subjects.

RESULTS

In both cases, the auditory-related regions, when compared to same regions in the control subjects, showed hypermetabolism in the left dorsolateral prefrontal cortex and the left precentral gyrus--similar to that in successful CI users who are prelingually deafened children or postlingually deafened adults. Both subjects had the ability to activate these areas, and this ability might be one of the reasons that accounts for such exceptionally good performance in older prelingually deaf CI users. As for the visual-related regions, hypometabolism was observed in Brodmann areas 18 and 19, and this finding might be related to the intensive auditory-verbal/oral education that the subjects had received since childhood.

CONCLUSIONS

Despite the limits imposed by the small sample size and the spatial resolution of positron emission tomography, this study yielded insights into the nature of the brain plasticity in prelingually deafened adults who are successful CI users.

Genetic syndromes involving hearing

OBJECTIVE

The fundamental processes involved in the mechanism of hearing seem to be controlled by hundreds of genes and hereditary hearing impairment may be caused by a large variety of genetic mutations in different genes. Approximately 150 loci for monogenic syndromic and non-syndromic hearing impairment (HI) disorders have been mapped to the human genome. The identification of these genes and functional analysis of the proteins they encode, are paving the way towards a better understanding of the physiology and pathophysiology of the auditory system. To date, approximately 50 causative genes have been identified.

METHODS

The clinical and neuroradioldical findings of syndromal hearing impairment are analysed.

RESULTS

This paper presents an updated report on genetic syndromes in which a hearing impairment is involved, with a particular attention to the ones associated with external ear and craniofacial malformations.

CONCLUSIONS

Concepts in human genetics are rapidly evolving together with technologies. The concept itself of gene is changing. A genetic diagnosis of syndromal hearing impairment has many practical consequences: it can implies specific prognosis, specific management, specific recurrence risk in relatives and, if the diagnosis is confirmed at the molecular level, possibility of a specific early prenatal diagnosis for severe syndromes. It is important to highlight the necessity that the pediatric otolaryngologist must have a close collaboration with a clinical geneticist and a neuroradiologist.

The benefits of sequential bilateral cochlear implantation for hearing-impaired children

CONCLUSION

Sequential bilateral implantation offers listening advantages demonstrable on speech recognition in noise and for lateralization. Whilst the trend was for shorter inter-implant intervals and longer implant experience to positively impact binaural advantage, we observed no contraindications for binaural advantage.

OBJECTIVE

To evaluate the benefits of sequential bilateral cochlear implantation over unilateral implantation in a multicentre study evaluating speech recognition in noise and lateralization of sound.

SUBJECTS AND METHODS

Twenty children, implanted bilaterally in sequential procedures, had the following characteristics: they were native German-speaking, were3 years or older and had a minimum of 1 year inter-implant interval and had between 2 months and 4 years 7 months binaural listening experience. Binaural advantage was assessed including speech recognition in noise using the Regensburg modification of the Oldenburger Kinder-Reimtest (OLKI) and lateralization of broadband stimuli from three speakers.

RESULTS

A significant binaural advantage of 37% was observed for speech recognition in noise. Binaural lateralization ability was statistically superior for the first and second implanted ear (p = 0.009, p = 0.001, respectively). Binaural experience was shown to correlate moderately with absolute binaural speech recognition scores, with binaural advantage for speech recognition and with binaural lateralization ability. The time interval between implants correlated in an inverse direction with binaural advantage for speech recognition.

Motor development of deaf children with and without cochlear implants

The purpose of this study was to investigate the impact of a cochlear implant (CI) on the motor development of deaf children. The study involved 36 mainstreamed deaf children (15 boys, 21 girls; 4- to 12-years old) without any developmental problems. Of these children, 20 had been implanted. Forty-three hearing children constituted a comparison group. Motor development was assessed by three standardized tests: the Movement Assessment Battery for Children, the Körperkoordinationstest für Kinder, and the One-leg standing test. Results showed that the hearing children performed on average significantly better than the deaf children (whether or not using a CI). Regarding the use of a CI, there was only a significant difference on one subtest between both groups, although there was a nonsignificant trend for the deaf +CI group to score somewhat worse on average than the deaf -CI group. This led to some significant differences between the hearing group and the deaf +CI group on measures requiring balance that did not hold for the hearing/deaf -CI comparison. Although this study could demonstrate neither a positive nor a negative impact of CI on balance and motor skills, the data raise the need for further, preferably longitudinal, research.

Local Dexamethasone Therapy Conserves Hearing in an Animal Model of Electrode Insertion Trauma-Induced Hearing Loss

HYPOTHESIS

The progressive loss of hearing that develops after electrode insertion trauma (EIT) can be attenuated by local dexamethasone (DXM) therapy.

BACKGROUND

Hearing loss (HL) that develops after cochlear implant EIT occurs in two stages in laboratory animals, that is, an immediate loss followed by a progressive loss. Direct infusion of DXM into the guinea pig cochlea can attenuate both ototoxin- and noise-induced HL.

MATERIALS AND METHODS

Auditory-evoked brainstem responses (ABRs) of guinea pigs were measured for 4 frequencies (i.e., 0.5, 1, 4, and 16 kHz) before, immediately after, and more than 30 days post-EIT for experimental (EIT,EIT + artificial perilymph, and EIT + DXM) and for the contralateral unoperated cochleae of each group. An electrode analog of 0.14-mm diameter was inserted through a basal turn cochleostomy for a depth of 3 mm and withdrawn. DXM in artificial perilymph was delivered immediately post-EIT into the scala tympani via a miniosmotic pump for 8 days.

RESULTS

The ABR thresholds of EIT animals increased progressively post-EIT. Contralateral unoperated cochleae had no significant changes in ABR thresholds. Immediately post-EIT, that is, Day 0, the DXM-treated animals exhibited a significant HL at 1, 4, and 16 kHz, but this HL was no longer significant by Day 30 compared with contralateral control ears.

CONCLUSION

The results from immediate local treatment of the cochlea with DXM in an animal model of EIT-induced HL suggest a novel therapeutic strategy for hearing conservation by attenuating the progressive HL that can result from the process of electrode array insertion during cochlear implantation.

Cochlear implantation in children: implications for the primary care provider

PURPOSE

To define hearing loss (HL), discuss the impact of HL on child development, and review the literature on cochlear implantation in children. The criteria for and the benefits and limitations of cochlear implantation in children, as well as the implications for the primary care provider with regard to children who have cochlear implants, are presented.

DATA SOURCES

Review of published literature on the topic.

CONCLUSIONS

A child's future development depends greatly on speech and language skills. Any type of HL can impact and may even hinder speech and language acquisition. It is therefore crucial to enforce early identification of HL. For severe to profoundly hearing-impaired children, cochlear implantation serves as an avenue for hearing and language development.

IMPLICATIONS FOR PRACTICE

Nurse practitioners ought to be up to date with criteria for and the benefits and risks of cochlear implantation. Health-related issues, such as vaccination, otitis media, and meningitis, must be assessed for and managed promptly.

Cochlear implants

Cochlear implants are cost-effective auditory prostheses that safely provide a high-quality sensation of hearing to adults who are severely or profoundly deaf. In the past 5 years, progress has been made in hardware and software design, candidate selection, surgical techniques, device programming, education and rehabilitation,and, most importantly, outcomes. Cochlear implantation in the elderly is well tolerated and provides marked improvement in auditory performance and psychosocial functioning.

D-JNKI-1 Treatment Prevents the Progression of Hearing Loss in a Model of Cochlear Implantation Trauma

HYPOTHESES

1) Hearing loss caused by electrode insertion trauma has both acute and delayed components; and 2) the delayed component of trauma-initiated hearing loss can be prevented by a direct delivery of a peptide inhibitor of the c-Jun N-terminal kinase cell death signal cascade, that is, D-JNKI-1, immediately after the electrode insertion within the cochlea.

BACKGROUND

Acute trauma to the macroscopic elements of the cochlea from electrode insertion is well known. The impact of trauma-induced oxidative stress within injured cochlear tissues and the efficacy of drugs (e.g., D-JNKI-1) to prevent apoptosis of damaged hair cells is not well defined.

METHODS

Hearing function was tested by pure-tone evoked auditory brainstem responses (ABRs) and distortion products of otoacoustic emissions (DPOAEs). D-JNKI-1 in artificial perilymph (AP) or AP alone was delivered into the scala tympani immediately after electrode trauma and for 7 days. Controls were nontreated contralateral and D-JNKI-1-treated ears without electrode insertion trauma.

RESULTS

There was no increase in the hearing thresholds of either the contralateral control ears or in the D-JNKI-1 without trauma animals. There was a progressive increase in ABR thresholds and decrease in DPOAE amplitudes after electrode insertion trauma in untreated and in AP-treated cochleae. Treatment with D-JNKI-1 prevented the progressive increase in ABR thresholds and decrease in DPOAE amplitudes that occur after electrode insertion trauma.

CONCLUSION

Hearing loss caused by cochlear implant electrode insertion trauma in guinea pigs has both acute and delayed components. The delayed component can be prevented by treating the cochlea with D-JNKI-1.

Auditory-visual fusion in speech perception in children with cochlear implants

Speech, for most of us, is a bimodal percept whenever we both hear the voice and see the lip movements of a speaker. Children who are born deaf never have this bimodal experience. We tested children who had been deaf from birth and who subsequently received cochlear implants for their ability to fuse the auditory information provided by their implants with visual information about lip movements for speech perception. For most of the children with implants (92%), perception was dominated by vision when visual and auditory speech information conflicted. For some, bimodal fusion was strong and consistent, demonstrating a remarkable plasticity in their ability to form auditory-visual associations despite the atypical stimulation provided by implants. The likelihood of consistent auditory-visual fusion declined with age at implant beyond 2.5 years, suggesting a sensitive period for bimodal integration in speech perception.

Mild Hypothermia Protects Auditory Function During Cochlear Implant Surgery

OBJECTIVE/HYPOTHESIS

Loss of auditory function after cochlear implant (CI) electrode insertion occurs in two stages in the laboratory rat. An immediate loss is followed by a progressive loss over 7 days. Similar stages of acute and progressive neuronal loss occur after trauma in the central nervous system where hypothermia has been shown to have a protective effect. We hypothesize that hypothermia has a similar protective effect against loss of auditory function caused by CI electrode insertion trauma.

METHODS

Thirty rats underwent surgery in one cochlea; the contralateral ear was an unoperated control. In the normothermia group, CI electrode insertion trauma was generated with rectal temperature maintained at 37 degrees C throughout the experiment. In the mild hypothermia group, electrode trauma was generated with rectal temperature lowered to 34 degrees C. In the surgical control group, mock surgery was performed at 37 degrees C. Multiple frequency auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) testing of all ears was performed before surgery, immediately afterward, and on postoperative days 3, 5, and 7.

RESULTS

Both ABR and DPOAE testing demonstrated partial loss of auditory function after electrode insertion trauma. However, the hypothermia group had significantly less functional loss in the immediate stage and no significant loss in the progressive stage.

CONCLUSION

Mild hypothermia protects auditory function during CI electrode insertion.

Parental decision-making in considering cochlear implant technology for a deaf child

OBJECTIVES

Advances in cochlear implant (CI) technology have increased the complexity of treating childhood deafness. We compare parental decision-making, values, beliefs, and preferences between parents of eligible and ineligible children in considering cochlear implants.

METHODS

Surveys were obtained from 83 hearing parents of deaf children. A subset of 50 parents also underwent semi-structured interviews. Nine hypothetical outcomes, ranging from mainstream success to poor mainstream outcome were created to measure parents' overall preferences and preference for specific outcomes for their child who is deaf.

RESULTS

Among parents of eligible children (n = 50), approximately 2/3 considered implantation (n = 33). The other 1/3 did not consider implantation. Parents who were eligible but did not consider implantation placed significantly lower priority on mainstream success over bilingual success (P < 0.03), and on the child's ability to speak versus sign (P < 0.02). They also showed significantly higher concerns on the cost of services in general and on the availability of resources offered at the local school district (both P > 0.05). Parents of ineligible children (n = 30) rarely considered implantation, even if they showed similar aspirations in mainstream outcomes (P = 0.003). Semi-structured interview data supported these findings.

CONCLUSIONS

The decision to consider cochlear implantation is strongly influenced by the eligibility and by professionals' recommendations. However, for some parents, the decision goes beyond eligibility and is determined by parental preferences, goals, values, and beliefs. This highlights the importance of careful audiologic evaluation and professionals' awareness of and sensitivity to parental goals, values, and beliefs in evaluating the child's candidacy.

Cochlear implantation in children under the age of two--what do the outcomes show us?

OBJECTIVES

Literature that discusses the benefits of cochlear implantation (CI) in children under the age of two is limited. Previous concerns about surgical risk have been raised and addressed; however, actual benefit in terms of outcomes needs to be clearly defined. This study evaluates outcomes of children implanted under the age of two and compares them to children implanted at a later age.

METHODS

Data were reviewed from the MED-EL International Children's study database. Thirty-seven children enrolled in the study have received cochlear implants before the age of two. Outcomes were assessed using the LiP and MTP tests and the MAIS and MUSS questionnaires pre-operatively and then at initial fitting, 1, 3, 6 and 12 months after first fitting and then annually thereafter.

RESULTS

Statistical analysis demonstrated that these children's scores improved significantly over time. Improvement was shown to occur at a quicker rate than for children implanted at an older age with the MTP and MUSS, but not with the LiP and the MAIS. Scores may be limited by sample size and the fact that children reached ceiling on some tests.

CONCLUSIONS

Results suggest a distinct advantage early implantation may have for severe to profoundly hearing impaired children. This may be particularly the case for skills necessary for development of receptive and expressive language skills.

Cochlear implants: indications in groups of patients with borderline indications. A review

Cochlear implants (CI) represent the current treatment for patients affected by profound sensorineural hearing loss (SNHL). Initially only deaf adult patients were considered to be candidates for a CI; however, the development of technology and matured experience have expanded the indications for cochlear implantation. Today, CIs are implanted in adults and children and broader indications are followed. There are, however, a number of patients who do not completely fulfill the current indications and who are potential candidates for CI. The duration of deafness and residual hearing represent prognostic indicators for CI performance; however, the candidacy of children with residual hearing and prelingually deafened adults are still under debate. Anatomical variants such as cochlear ossification, cochlear malformation and chronic otitis media represented and still represent for some surgeons a contraindication to CI. The otological experience of CI surgeons and the advent of auditory brainstem implants have changed the approach to these patients, who may still benefit from hearing rehabilitation. This paper briefly analyses and reviews the results obtained in these groups of patients, who were not, at least initially, considered to be candidates for cochlear implantation.

Cochlear Implant Candidacy and Surgical Considerations

Numerous changes continue to occur in regard to cochlear implant candidacy. In general, these have been accompanied by concomitant and satisfactory changes in surgical techniques. Together, this has advanced the utility and safety of cochlear implantation. Most devices are now approved for use in patients with severe to profound rather the prior requirement of a bilateral profound loss. In addition, studies have begun utilizing short electrode arrays for shallow insertion in patients with considerable low frequency residual hearing. This technique will allow the recipient to continue to use acoustically amplified hearing for the low frequencies simultaneously with a cochlear implant for the high frequencies. New hardware, such as the behind-the-ear speech processors, require modification of existing implant surgery. Similarly, the new perimodiolar electrodes require special insertion techniques. Bilateral implantation clearly requires modification of the surgical techniques used for unilateral implantation. The surgery remains mostly the same, but takes almost twice as long, and requires some modification since at a certain point, when the first device is in contact with the body, the monopolar cautery may no longer be used. Research has already begun on the development of the totally implantable cochlear implant (TICI). This will clearly require a modification of the surgical technique currently used for the present semi-implantable devices. In addition to surgically burying the components of the present cochlear implant, we will also have to develop techniques for implanting a rechargeable power supply and a microphone for the TICI. The latter will be a challenge, since it must be placed where it is capable of great sensitivity, yet not exposed to interference or the risk of extrusion. The advances in design of, and indications for, cochlear implants have been matched by improvements in surgical techniques and decrease in complications. The resulting improvements in safety and efficacy have further encouraged the use of these devices. We anticipate further changes in the foreseeable future, for which there will likely be surgical problems to solve.