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 implants in patients with radical cavity

Treatment of patients with severe bilateral hearing loss by cochlear implants usually requires normal temporal bone anatomy. The authors report one case in which the electrophysiological criteria for cochlear implant were fulfilled. However, the patient showed unfavourable anatomy because of a radical mastoid cavity on the suitable side and a congenital anomaly on the opposite side. As a first step the radical cavity was opened from a retroauricular incision and completely de-epithelialized. Thereafter, a retroauricular full-thickness skin flap was formed and rotated into the cavity; the retroauricular incision was not closed. Six months later a cochlear implant (Clark-Nucleus system) was positioned after undermining the flap described above. This surgical technique allows us to provide patients with radical cavities with implants under the usual sterile conditions and avoids contact of the implant with the body surface.     

Cochlear implants.

All presently devised single channel devices generate a primitive sensation of hearing by the mechanism of 'periodicity pitch'. No 'place pitch' encoding is possible. Although some enhancement of communicative skills with lip reading results, unaided speech discrimination is not possible. Definite psychological advantages for the totally deaf have been observed with these simple devices. Multiple segments of auditory nerve must be stimulated in a manner which will simulate the complex patterns of neural activity necessary for speech discrimination. Electrode optimization and the pathophysiological consequences of electrical stimulation of the auditory nerve can best be determined in animals. The perceptual consequences of electrical stimulation of the auditory nerve, however, can best be determined in man. How much we will have to innovate the methods of aural rehabilitation will depend upon how well we can generate perceptual speech patterns by electrical excitation of the auditory nerve.     

Cochlear implants in post-lingually deafened patients

CONCLUSION: Post-lingually deafened patients had good speech intelligibility scores with cochlear implantation. The age at the operation, duration of deafness, and the number of electrodes outside the cochlea showed only weak correlation with the postoperative performance, which warrants cochlear implantation in elderly patients and patients with a long history of deafness and leaving dummy electrodes outside the cochlea. Patients with cochlear obstruction showed comparable performance to patients with an open cochlea. OBJECTIVE: To evaluate the background and performance of post-lingually deafened cochlear implantation recipients. PATIENTS AND METHODS: Preoperative and intraoperative factors were collected for 109 cochlear implant subjects. Speech intelligibility scores were obtained and the effects of preoperative and intraoperative factors on postoperative performance were evaluated. RESULTS: The average speech intelligibility score was 85.1% for vowels, 41.1% for consonant-vowel (CV) syllables, and 80.4% for phrases. The correlation coefficient between the age at the operation, the duration of deafness, and the number of electrodes outside the cochlea and the postoperative performance was between 0.03 and -0.27. Patients with cochlear obstruction and patients with open cochlea did not show significant differences in speech intelligibility tests. The onset of deafness (progressive vs sudden) did not have an effect on the speech intelligibility test.     

Cochlear implantation in patients with Meniere's disease: A systematic review

BackgroundMeniere's disease (MD) is an idiopathic disorder of the inner ear, which manifests as cochleo-vestibular dysfunction. Hearing loss will progress to a profound levelin a subset of patients with MD, and vestibular interventions can independently cause loss of hearing. The aim of this study was to systematically review the published literature describing the safety and efficacy of CI in patients with MD.Materials and methodsA systematic literature review was conducted in accordance PRISMA guidelines to identify articles that assessed at least one functional outcome in patients with MD who underwent CI. Demographic information, disease history, MD symptoms, outcomes measures, and complications related to CI were extracted from included studies.ResultsIn total, 17 studies were included, and 182 patients with MD underwent CI. The weighted-mean age was 61.9 years (range 27–85). Study objective and methodology varied, and there was significant heterogeneity in CI outcome measures reported. In total, 179 (98.3%) of 182 patients reported objective improvements in at least one hearing metric after CI. A total of 69 patients (37.9%) reported vertigo or severe dizziness prior to CI, compared to 22 patients (15.4%) postoperatively. Two studies reported significant reductions in postoperative Tinnitus Handicap Inventory score (THI). Quality of life assessments varied between studies. Complications rates were low with only nine patients (4.9%) reporting a serious CI-related complication.ConclusionsThis systematic review evaluated 17 studies describing the safety and efficacy of CI in patients with MD and encountered many challenges due to small sample sizes, and heterogeneity in study design and outcomes measured. Despite these limitations, this study of 182 patients is to the best of our knowledge the largest systematic review evaluating the safety and efficacy of CI in MD. The results of this study support the need for a standardized approach to evaluating outcomes of CI in patients with MD in future studies.     

Cochlear implants and magnetic resonance scans: A case report and review

Abstract

Objective and importance

Traditionally, magnetic resonance imaging (MRI) was contraindicated for patients with cochlear implants (CIs), due to concern about device displacement, overheating of the device or tissues, or direct damage to the device electrode. In addition, image artifact from the device magnet gave poor imaging information in the cranial and upper cervical spine region. Today, MRI is increasingly required in patients who have undergone cochlear implantation, and CI design and MRI protocols have therefore changed to allow implanted patients to safely enter the MRI field, in some cases without removal of the CI internal magnet.

Clinical presentation

We present a patient with bilateral CIs who required MRI to investigate new neurological symptoms. Despite tight head bandaging applied according to our protocol, MRI at 1.5 T led to bilateral skin reactions and displacement of the magnet on the left. Both magnets were subsequently removed to allow the skin reactions to settle and for further imaging without artifact. The functioning of the patient's implants was not affected.

Conclusion

The final decision to recommend that a patient with a CI undergoes MRI, with or without removal of the internal magnet, requires close cooperation between the CI team, the physician requiring the scan, and the radiology team involved in the patient's care. The case study we present highlights the need for patients to be fully informed of the risks involved.     

Cochlear implants in adults: indications and realizations. Part I: Diagnosis,operation techniques and results

From the technical point of view, cochlear implant (CI) surgery in adults is a well established procedure. Pre- and postoperative evaluation, surgical approach and rehabilitation programs are standardized, presenting CI as a low risk procedure with rare complications similar to those of middle ear surgery. Modern advanced CI devices offer technical reliability and multiple speech encoding strategies and recently, even small processors which are worn behind the ear. Further technical advances are continuously available, even for implanted patients. Upgrading is usually easy because the outer parts of the implant are exchangeable and software upgrades can be transmitted transcutaneously to the implant. Assuming that medical and rehabilitation requirements are available, there are only very few indications against CI in adults. Candidate patients should therefore be transferred to CI-centres where a decision can be taken depending on presurgical evaluation results.     

Cochlear implants in adults: indications and realization. Special cases and technical parameters of the implantation systems

From the technical point of view, cochlear implant (CI) surgery in adults is a well established procedure. Pre- and postoperative evaluation, surgical approach and rehabilitation programs are standardized, presenting CI as a low risk procedure with rare complications similar to those of middle ear surgery. Part 1 described the diagnostics, surgical procedure and possible complications. The second part will cover the contraindications, special cases as well as the technical parameters of the modern implant system.     

语后聋长期全聋耳的人工耳蜗植入

目的 探讨语后聋长期全聋耳的人工耳蜗植入术后效果.方法 双侧听力下降时间不同步、双侧耳聋程度不一致的语后聋患者4例,对重度聋时间较长(均>10年)、耳聋程度较重侧进行植入人工耳蜗,分别在开机后6个月、12个月,使用心理物理学测试(T/C值),术后声场内最佳助听条件下言语频率平均听阈(pure-tonethreshold average,PTA).安静及噪声环境巾的言语识别率(HINT句表),单音节词识别率(HOPE词表),汉语声调识别(MESP),听觉行为分级标准(CAP),成人生活质量调奁问卷等评价指标,评价其术后听觉言语康复效果.结果 4例受试者在开机半年至一年内均达到了较为理想的康复效果,PTA接近或达到正常水平;安静环境中的言语识别率平均达到90%以上,噪声环境中平均达到70%;植入者可以很好地识别汉语声调;人工耳蜗为植入者带来了较高的社会效益.患者对人工耳蜗的植入效果均表示满意.结论 4例受试者都选择重度聋时间较长侧作为人工耳蜗植入侧,开机后均在较短时间内获得了良好的听觉言语康复效果,充分发挥了人工耳蜗的功能和优势的同时.听力相对较好侧耳还町继续佩戴助听器,保留了患者双耳聆听和日后接收其它治疗的机会,最大限度地为患者创造了最佳聆听条件.     

蜗神经发育不良患者的人工耳蜗植入

目的:观察蜗神经发育不良的患儿人工耳蜗植入术后的效果,探讨术前HRCT和MRI对蜗神经发育不良的诊断及评估价值。方法:回顾性分析10例蜗神经发育不良患儿的术前影像学资料及人工耳蜗植入术后对声音的反应和语训效果。结果:3例(6耳)HRCT提示双侧内耳道狭窄,耳蜗、前庭和半规管发育正常,MRI提示蜗神经发育不良。7例(14耳)HRCT提示双侧内耳道正常,其中1例IP-Ⅰ型,伴前庭半规管发育不良,6例双侧耳蜗、前庭和半规管发育正常;7例MRI提示蜗神经发育异常。10例患儿均行人工耳蜗植入,经过12～32个月的随访,3例学会简单语言,MAIS量表、CAP分数及SIR分级较前提高;1例虽能讲话,但口齿含糊;4例对声音有反应,仅能说"爸爸"、"妈妈"等单音节词;2例无反应(1例取出)。10例蜗神经发育不良患儿同其他蜗神经发育正常儿童相比,术后康复情况明显落后。结论:对蜗神经缺陷患儿,术前仅做颞骨HRCT检查易漏诊,结合内耳道MRI(含内耳道斜矢状位重建)已成必须。若发现疑似病例,应慎重筛选,告知行人工耳蜗植入效果不佳的巨大可能性,严格掌握手术指征。     

Cochlear implants and health status: a comparison with other hearing-impaired patients

Eighty-four adult cochlear implant (CI) users were compared with 3 other groups of severely to profoundly hearing impaired adults concerning quality of life (QOL): 1) 19 CI candidates who were accepted as candidates for implantation, but who were not operated on; 2) 16 CI candidates whose impairment was not severe enough for implantation; and 3) 60 users of acoustic hearing aids. Generic and disease-specific QOL questionnaires were used. The CI group scored significantly better than the CI candidates who met the criteria for implantation, but who were not operated on, on 2 of 6 categories of a disease-specific QOL measure. The CI patients had significantly less anxiety and depression than the unoperated CI candidates who met the criteria for implantation. Validation and reliability testing of 2 disease-specific QOL measures were performed by factor analyses.     

Cochlear implants: growing pains

OBJECTIVES/HYPOTHESIS: The objective was to make familiar the problems faced in the application of cochlear implants to the half-million to a million severe to profoundly deaf individuals who are potential beneficiaries of this technology. STUDY DESIGN: Observations accumulated during 23 years as Medical Director of the Manhattan Eye Ear Throat Hospital Cochlear Implant Center. METHODS: The author reviewed insights gained while directing the Cochlear Implant Center since the early 1980s at Manhattan Eye, Ear and Throat Hospital (New York, NY). RESULTS: The rapid application of cochlear implant technology for patients with severe to profound hearing losses is creating critical problems. It is being hampered by inadequate reimbursement. There is a critical shortage of cochlear implant-trained audiologists, who are an essential keystone in the application of this technology. These audiologists are required to provide lifelong audiological services to patients who have received cochlear implants. At the same time, they must evaluate the exponentially growing number of new candidates. CONCLUSION: The restoration of hearing with cochlear implants provides an enormous educational and societal benefit. However, the existing health care delivery system limits the application of cochlear implant technology. University audiological training programs must expand their curricula to include cochlear implant-related courses. The existing rehabilitation audiologist delivery system could be applied to provide long-term, community-based cochlear implant services.     

Cochlear implantation in patients with enlarged vestibular aqueduct. A case series with literature review

Objectives: To report our institutional experience of the management of patients with enlarged vestibular aqueduct (EVA) and compare it to the literature.

Methods: We carried out a retrospective review of patients’ records from 1993 to 2015. The age, sex, associated malformations, relevant past medical history, genetic screening results, possible surgical incident, implant model and duration of follow- up, outcome in terms of Categories of Auditory Performance (CAP scores), and integration or resuming mainstream school or work were recorded.

Results: We had 11 patients (six boys and five girls) with EVA who underwent cochlear implant surgery in our center during the 22-year study period, out of a total of 827 implanted (1.3%). The mean age at surgery was 8.9 years ranging from 0.6 to 35 years. EVA was bilateral in 10 cases, isolated anatomical finding in seven cases, and associated with other malformations in four. Cochlear implantation was bilateral in five cases and unilateral in six. The mean follow- up duration was 48.3 months (range: 3–120). No postoperative complication was observed and all the patients could regain a serviceable hearing, attending normal school and working normally.

Conclusion: EVA is frequently observed in the deaf population without an identifiable cause. The hearing loss is usually progressive and may result in cochlear implantation which has proved its efficiency in rehabilitating EVA patients.     

Cochlear implants: histological data

We have performed a histological examination of the pars petrosa of 13 implanted patients. Morphological data were confronted with the clinical findings. The results of this study show that the nerve elements stimulated by the electrode are the cells of the spiral ganglion, and that a small number of ganglionic cells, as few as 10% of the normal figure, is compatible with auditory perception by electrical stimulation. Furthermore, all the implanted pars petrosa were the seat of a fibrosis and neo-ossification reaction around and sometimes even beyond the tip of the electrode. The trauma caused by the insertion of the electrode into the cochlea involved the sensorial cells of the organ of Corti and the dendritic populations in the lamina spiralis, but the cells of the spiral ganglion were spared. Prolonged electrical stimulation (14 years in 1 case) does not appear to have any deleterious effect on the survival of the spiral ganglion, of the cochlear nerve or of the cochlear nucleus.     

Cochlear implants for congenital deformities.

There have been few accounts of multi-channel cochlear implants in patients with congenital structural deformities of the inner ear which are associated with severe and sometimes progressive deafness. These malformations can now be recognized easily on 2 plane thin section high resolution CT studies which are mandatory for the pre-implantation assessment. However, no attempt seems to have been made to describe which of these malformations would be suitable for an implant or for which would this procedure be contra-indicated. True Mondini deformity of both the cochlea and dilated vestibular aqueduct type would appear suitable for a multi channel implant, but this type of implant should not be used for a primitive otocyst, severe labyrinthine dysplasia or the characteristic X-linked deformity.     

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.     

Cochlear implants. Present and future

The perfect cochlear implant has eluded the many research teams around the world that are studying it. In the hope that someone may develop one system that is clearly better than the others, I believe that each team should pursue its own ideas and methods. We have at least another 20 years of step-by-small step development if we are to continue to improve the cochlear implant.     

Cochlear implants in children

The resources and areas of expertise necessary to establish and maintain a successful children's cochlear implant program is discussed. Insights based on experience with a pediatric patient population are presented.