Systematic reviews of the effectiveness and cost-effectiveness of multi-channel unilateral cochlear implants for adults

Clin. Otolaryngol. 2010, 35 , 87–96 Objective: In the UK approximately 3% of over 50 years olds and 8% of over 70 year olds have severe (794–94 dBHL) to deafness. As deafness increased, hearing aids become increasingly ineffective. Cochelear implants can provide an alternative treatment. Objective of review: To bring together the research evidence through the robustness of a systematic review of the effectiveness of unilateral cochlear implants for adults. We also sought to systematically review the published literature on cost-effectiveness. Types of review: Systematic review. Search strategy: This examined 16 electronic databases, plus bibliographies and references for published and unpublished studies from inception to june 2009. Evaluation method: Abstracts were independently assessed against inclusion criteria by two researchers were compared and disagreements resolved. Included papers were then retrieved and further independently assessed in a similar way. Remaining studies had their data independently extracted by one of five reviewers and checked by another reviewer. Results: From 1,580 titles and abstracts nine studies were included. These were of variable quality; some study's results should be viewed with caution. The studies were too hetrogeneous to pool the data. However, overall the results firmly supported the use of unilateral cochler implants for severe to profoundly deaf adults. Additionally, four UK based economic evaluations found unilateral cochlear implants to be cost-effectivene in adults at UK implants centres. Conclusion: The methodologically weak but universally positive body of effectiveness evidence supports the use of unilateral cochlear implants in adults. Previous economic evaluations indicate that such implants are likely to be cost-effective.     

A systematic review of the effectiveness and cost‐effectiveness of bilateral multichannel cochlear implants in adults with severe‐to‐profound hearing loss

Clin. Otolaryngol. 2012, 37 , 342–354 Background: In the UK, approximately 10 000 people have cochlear implants, more than 99% with a unilateral implant. Evidence shows that adults implanted bilaterally may benefit from binaural advantages; however, systematic review evidence is limited. Objectives of the review: To conduct a systematic review to discover the evidence for effectiveness and cost‐effectiveness of using bilateral cochlear implants in adults with severe‐to‐profound hearing loss by comparing their effectiveness with unilateral cochlear implantation or unilateral cochlear implantation and acoustic hearing aid in the contralateral ear. Type of review: Systematic review. Search strategy: This examined 16 electronic databases, plus bibliographies and references for published and unpublished studies. Evaluation method: Abstracts were independently assessed against inclusion criteria by two researchers, and disagreements were resolved. Selected papers were then retrieved and further independently assessed in a similar way. Included studies had their data extracted by one reviewer and checked by another. Results: Searches yielded 2892 abstracts producing 19 includable studies. Heterogeneity between studies precluded meta‐analysis. However, all studies reported that bilateral cochlear implants improved hearing and speech perception: one randomised controlled trial found a significant binaural benefit over the first ear alone for speech and noise from the front (12.6 ± 5.4%, P < 0.001) and when noise was ipsilateral to the first ear (21 ± 6%, P < 0.001); and another found a significant benefit for spatial hearing at 3 and 9 months post‐implantation compared with pre‐implantation [mean difference (sd ) scores: 3 months = 1.46 (0.83–2.09), P < 0.01].Quality of life results varied, showing bilateral implantation may improve quality of life in the absence of worsening tinnitus. Limited cost‐effectiveness evidence showed that bilateral implantation is probably only cost‐effective at a willingness‐to‐pay threshold above £62 000 per quality adjusted life year. Conclusions: Despite inconsistency in the quality of available evidence, the robustness of systematic review methods gives weight to the positive findings of included studies demonstrating that bilateral implantation is clinically effective in adults but unlikely to be cost‐effective.     

Post-lingual deafness: benefits of cochlear implants vs. conventional hearing aids

The technological advances in cochlear implants and processing strategies have enabled subjects affected by severe to profound hearing loss to hear sounds and recognize speech in various different degrees. The variability of hearing outcomes in subjects with post-lingual deafness has been significant and cochlear implant indications have been extended to include an ever larger population.ObjectiveThis paper aims to look into the groups of post-lingual deafness patients to find where cochlear implants have yielded better outcomes than conventional hearing aids.Materials and MethodsReview the literature available on databases SciELO, Cochrane, MEDLINE, and LILACS-BIREME. The publications selected for review were rated as A or B on evidence strength on the day of the review. Their authors analyzed and compared hearing aids and cochlear implants in populations of post-lingually deaf patients. Study Design: Systematic review.ResultsEleven out of the 2,169 papers searched were found to be pertinent to the topic and were rated B for evidence strength. Six studies were prospective cohort trials, four were cross-sectional studies and one was a clinical trial.ConclusionThe assessment done on the benefits yielded by post-lingually deaf subjects from cochlear implants showed that they are effective and provide for better results than conventional hearing aids.     

Combined electro‐acoustic stimulation: a beneficial union?

Background: The most pressing problem facing cochlear implant research is no longer making artificial hearing a reality. Instead, it is to develop devices that can more clearly reflect the capabilities of the human auditory system. Current cochlear implants rarely provide adequate pitch perception. As hearing loss commonly affects higher, more than lower frequencies, a possible solution is to preserve acoustic hearing at low frequencies by inserting a short electrode array and thus deliver combined electro‐acoustic stimulation (EAS). Objective of review: To determine whether individuals with severe‐to‐profound high‐frequency hearing loss have realised this predicted benefit of combined EAS, over conventional cochlear implants, with respect to pitch. Type of review: A systematic review of publications pertaining to the benefits of combined EAS over conventional cochlear implantation, with specific reference to pitch perception. Search strategy: A systematic literature search was conducted across multiple databases and supplemented by searching the reference lists of relevant trials and identified reviews. Results: The included studies suggest an overall benefit of combined EAS, over conventional cochlear implants, with respect to pitch. In addition, (i) 13% sustained a total loss of low‐frequency hearing post‐implantation of the short electrode array and, (ii) 24% had >20 dB hearing loss across all frequencies and/or total hearing loss. Conclusions: For patients with severe‐to‐profound high‐frequency hearing loss combined EAS appears to offer a significant, everyday, long‐term benefit. However, further clinical trials with larger numbers of candidates are necessary to confirm this finding. The risks involved cannot be ignored, but there is potential for a variety of strategies to improve the safety margin.     

Nasalance in Cochlear Implantees

Objectives

Speech intelligibility is severely affected in children with congenital profound hearing loss. Hypernasality is a problem commonly encountered in their speech. Auditory information received from cochlear implants is expected to be far superior to that from hearing aids. Our study aimed at comparing the percentages of nasality in the speech of the cochlear implantees with hearing aid users and also with children with normal hearing.

Methods

Three groups of subjects took part in the study. Groups I and II comprised 12 children each, in the age range of 4-10 years, with prelingual bilateral profound hearing loss, using multichannel cochlear implants and digital hearing aids respectively. Both groups had received at least one year of speech therapy intervention since cochlear implant surgery and hearing aid fitting respectively. The third group consisted of age-matched and sex-matched children with normal hearing. The subjects were asked to say a sentence which consisted of only oral sounds and no nasal sounds ("Buy baby a bib"). The nasalance score as a percentage was calculated.

Results

Statistical analysis revealed that the children using hearing aids showed a high percentage of nasalance in their speech. The cochlear implantees showed a lower percentage of nasalance compared to children using hearing aids, but did not match with their normal hearing peers.

Conclusion

The quality of speech of the cochlear implantees was superior to that of the hearing aid users, but did not match with the normal controls. The study suggests that acoustic variables still exist after cochlear implantation in children, with hearing impairments at deviant levels, which needs attention. Further research needs to be carried out to explore the effect of the age at implantation as a variable in reducing nasality in the speech and attaining normative values in cochlear implantees, and also between unilateral versus bilateral implantees.     

Task force Guideline of Brazilian Society of Otology – hearing loss in children – Part II — Treatment

ObjectivesTo provide an overview of the main evidence-based recommendations for the diagnosis of hearing loss in children and adolescents aged 0–18 years.MethodsTask force members were educated on knowledge synthesis methods, including electronic database search, review and selection of relevant citations, and critical appraisal of selected studies. Articles written in English or Portuguese on childhood hearing loss were eligible for inclusion. The American College of Physicians’ guideline grading system and the American Thyroid Association’s guideline criteria were used for critical appraisal of evidence and recommendations for therapeutic interventions.ResultsThe topics were divided into 2 parts: (1) treatment of sensorineural hearing loss: individual hearing aids, bilateral cochlear implants, cochlear implants in young children, unilateral hearing loss, and auditory neuropathy spectrum disorder; and (2) treatment of conductive/mixed hearing loss: external/middle ear malformations, ventilation tube insertion, and tympanoplasty in children.ConclusionsIn children with hearing loss, in addition to speech therapy, Hearing AIDS (HAs) or implantable systems may be indicated. Even in children with profound hearing loss, both the use of HAs and behavioral assessments while using the device are important.     

The Norwegian Hearing in Noise Test

Abstract

Objective: The Toy Discrimination Test measures children's ability to discriminate spoken words. Previous assessments of reliability tested children with normal hearing or mild hearing impairment, and most studies used a version of the test without a masking sound. We assessed test-retest reliability for children with hearing impairment using maskers of broadband noise and two-talker babble. Design: Stimuli were presented from a loudspeaker. The signal-to-noise ratio (SNR) was varied adaptively to estimate the speech-reception threshold (SRT) corresponding to 70.7% correct performance. Participants completed each masked condition twice. Study sample: Fifty-five children with permanent hearing impairment participated, aged 3.0 to 6.3 years. Thirty-four children used acoustic hearing aids; 21 children used cochlear implants. Results: For the noise masker, the within-subject standard deviation of SRTs was 2.4 dB, and the correlation between first and second SRT was + 0.73. For the babble masker, corresponding values were 2.7 dB and + 0.60. Reliability was similar for children with hearing aids and children with cochlear implants. Conclusions: The results can inform the interpretation of scores from individual children. If a child completes a condition twice in different listening situations (e.g. aided and unaided), a difference between scores ≥ 7.5 dB would be statistically significant (p <.05).     

MUSIC AND COCHLEAR IMPLANTS

Currently, most people with modern multichannel cochlear implant systems can understand speech in qui-et environment very well. However, studies in recent decades reported a lack of satisfaction in music percep-tion with cochlear implants. This article reviews the literature on music ability of cochlear implant users by presenting a systematic outline of the capabilities and limitations of cochlear implant recipients with regard to their music perception as well as production. The review also evaluates the similarities and differences be-tween electric hearing and acoustic hearing regarding music perception. We summarize the research results in terms of the individual components of music (e.g., rhythm, pitch, and timbre). Finally, we briefly intro-duce the vocal singing of prelingually-deafened children with cochlear implants as evaluated by acoustic measures.     

Comparison of outcomes in children with hearing aids and cochlear implants

Abstract

Objectives

The purpose of this study was to document the performance of a group of children with moderately severe to severe hearing loss who use hearing aids on a range of speech recognition, speech–language, and literacy measures and to compare these results to children with severe to profound hearing loss, who have learned language through cochlear implants.

Methods

This study involved 41 children with bilateral sensorineural hearing impairment, aged 6–18 years. Twenty children had moderately severe/severe hearing loss and used hearing aids, and 21 had severe to profound hearing loss and used cochlear implants. Communication and academic skills were assessed using speech recognition tests and standardized measures of speech production, language, phonology, and literacy.

Results

The two groups did not differ in their open-set speech recognition abilities or speech production skills. However, children with hearing aids obtained higher scores than their peers with cochlear implants in the domains of receptive vocabulary, language, phonological memory, and reading comprehension. The findings also indicate that children with moderately severe or severe hearing loss can develop spoken language skills that are within the range expected for normal hearing children.

Conclusions

School-aged children with moderately severe and severe hearing loss performed better in several domains than their peers with profound hearing loss who received cochlear implants between age 2 and 5 years. Further research is required to evaluate the benefits of hearing aids and cochlear implants in children with hearing loss who are diagnosed and receive intervention within the first year of life.     

Performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implant: a systematic review

IntroductionCurrently, there are no doubts about the benefits of cochlear implants for the development of children with severe or profound hearing loss. However, there is still no consensus among researchers and professionals regarding the benefits for the improvement of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants.ObjectiveReview the available evidence in the literature to answer the following: “What is the performance of hearing skills in children with auditory neuropathy spectrum disorder using cochlear implants?”MethodsSystematic review of the literature through electronic database consultation, considering publications in the period 2002–2013.ResultsTwenty-two studies met the criteria and were included in the systematic review.ConclusionThe analyzed studies demonstrated that after cochlear implant surgery, individuals with auditory neuropathy spectrum disorder improved their performance of hearing skills and had similar performance to that of children with sensorineural hearing loss using cochlear implant.     

人工耳蜗植入和助听器配戴儿童声调识别的对比实验研究

目的探讨人工耳蜗植入儿童和助昕器配戴儿童在声调识别方面是否存在差异；考查人工耳蜗开机时间、入园康复时间，儿童的年龄、性别等因素对声调识别是否有影响。方法采用《言语听觉反应评估》（evaluation of auditory responses to speech，EARS）中的“封闭式声调测试”作为测试材料．对61名3～6岁聋儿（其中人工耳蜗植入儿童31名，助昕器配戴儿童30名）进行声调识别的测试，利用SPSS软件对结果进行统计分析。结果助昕器配戴儿童在声调识别的精确性上优于人工耳蜗植入聋儿；人工耳蜗开机时间对声调测试成绩没有明显的影响；康复时间、聋儿的年龄和声调测试成绩呈正比；聋儿的性别和声调测试成绩无关。结论助昕设备类型、康复时间、年龄等对声调识别的成绩有一定影响，这些因素之间可能存在相互作用，有待进一步探讨。     

双耳双模式助听儿童情感语调感知特征

目的探讨单侧人工耳蜗植入儿童对侧配戴助听器能否提升其情感语调识别能力,不同的情绪语调识别是否存在难度差异。方法选取35例(男15例,女20例)双耳双模式助听的重度、极重度感音神经性听力损失儿童,组内比较单侧人工耳蜗助听状态和双模式助听两种状态下儿童的情感语调识别特征。结果双耳双模式助听状态下听障儿童的语调得分极显著高于单侧人工耳蜗助听状态(P<0.01),识别率总体提升了16.65%。开心语调提升了20.59%,生气语调提升了19.21%,难过语调提升了13.23%。个体数据分析发现,有82.85%的儿童体现出双耳双模式优势。两种助听状态下,生气语调识别得分显著高于开心和难过(P<0.05),双耳双模式助听状态下,23.53%的儿童会将开心感知为难过语调,22.79%的儿童会将难过感知为开心语调。结论相比于单侧人工耳蜗植入,儿童通过双模式助听可以获得情感语调感知优势;两种助听模式下,生气语调的识别均比开心和难过容易,开心和难过语调容易混淆。频率变化可能是儿童感知情感语调的重要线索,提示在康复训练中应予以重视。     

小龄耳聋儿童听觉能力发展问卷评估

目的评估选配助听器和人工耳蜗植入儿童的听觉能力,为制定合理的康复训练计划提供资料和依据。方法调查对象为50名语前聋儿童(患儿组),其中使用人工耳蜗和助听器者各25名;生理年龄为3至65个月,平均28±14个月;听力年龄为0至21个月,平均8±5个月。使用小龄儿童听觉发展测评工具中的《小龄儿童听觉发展问卷之评价儿童听觉行为的父母问卷》进行调查,问卷由家长填写,结果与引自小龄儿童听觉发展测评工具中听力正常儿童的正常值进行对比分析。结果患儿选配助听器或植入人工耳蜗的平均月龄为20±13个月。3岁以下32人(64%,32/50),3岁以上18人(36%,18/50)。33名患儿出生时接受过听力筛查(66%,33/50),17名未接受过听力筛查(34%,17/50)。随听力年龄的增长,各组儿童的听觉能力均不断提高,使用人工耳蜗患儿的听觉能力进步速度比佩带助听器的患儿快,3岁以下选配助听器或植入人工耳蜗的患儿听觉能力的发展速度比3岁以上快;各组患儿听觉能力的发展速度均比正常儿童慢。结论耳聋患儿使用助听装置时间越长,其听觉能力发育的越好。重度以上耳聋儿童宜早期进行人工耳蜗植入。     

学龄前听障儿童助听后言语流畅性的特征及影响因素

目的 分析学龄前听障儿童助听后言语流畅性的特征,探讨辅听装置、年龄、性别、语训时长对其言语流畅性的影响.方法 以109例3.5~6.5岁学龄前健听及听障儿童为研究对象,其中健听儿童30例(健听组),双耳佩戴助听器的听障儿童28例(助听器组),右耳植入人工耳蜗的听障儿童26例(人工耳蜗组),同时佩戴助听器和人工耳蜗双耳双模式助听的听障儿童25例(双模式组),通过主题对话的形式分别采集各组儿童的语音样本,比较各组儿童在自发性言语语言任务下的语速、停顿、重复和拖延差异;分析辅听装置、年龄、性别、语训时长等因素对听障儿童言语流畅性的影响.结果 ①健听组儿童的语速显著高于其他三组(P<0.05),健听组停顿次数显著低于人工耳蜗组(P=0.001)和双模式组(P=0.032);健听组拖延次数显著低于助听器组(P=0.001)和双模式组(P=0.001),极显著低于人工耳蜗组(P<0.001);②不同性别听障儿童语速、停顿、重复次数和拖延次数差异无统计学意义(P>0.05),而助听器组语速显著高于人工耳蜗组(P=0.045),人工耳蜗组停顿次数显著高于助听器组(P=0.028);3.5~5岁听障儿童语速显著低于5.1~6.5岁组(P=0.042);语训0~2.5年听障儿童语速显著低于语训>2.5年者(P=0.002),停顿及重复次数均高于语训>2.5年者(分别P=0.047,P=0.02).结论 听障儿童的语速低于健听儿童,停顿次数、拖延次数高于健听儿童;年龄、辅听装置、语训时长影响学龄前听障儿童的言语流畅性,性别影响不大.     

Phonological abilities of hearing-impaired Cantonese-speaking children with cochlear implants or hearing AIDS.

PURPOSE: This article examined the phonological skills of 2 groups of Cantonese-speaking children with prelingual, profound bilateral hearing loss. The phonological abilities of 7 children fitted with hearing aids were compared with the abilities of 7 children who wore cochlear implants. METHOD: Participants in each group ranged in age from 5;1 to 6;4 years. The participants were asked to name 57 pictures and retell 2 stories. Phonological abilities were described in terms of the participants' phonological units and the phonological processes used. The participants' perception of single words was assessed using a Cantonese phonology test that includes tonal, segmental, and semantic distracters. RESULTS: All except 1 participant had incomplete phonetic repertories. All participants showed complete vowel and tone inventories. The study group used both developmental rules and nondevelopmental phonological rules. For perception of single words, participants chose the target word most often. The cochlear implant users had a significantly higher percentage correct score for consonant production than hearing aid users. CONCLUSIONS: The prediction that Cantonese children wearing cochlear implants would have better phonological skills than children having hearing aids with a similar degree of hearing loss was confirmed. Cochlear implant usage appeared to promote consonant feature production development to a greater degree than did the use of a hearing aid.     

The role of sound in adult and developmental auditory cortical plasticity

The purpose of the current review is to highlight the role of the acoustic environment in auditory cortical plasticity. In order do this we have reviewed our past studies on auditory cortical plasticity based on long-latency evoked potential recordings in humans following cochlear implantation, and multiple single-unit recordings from cat auditory cortex following noise trauma and exposure to a non-deafening acoustic environment. The results of these studies, and those of other investigators highlighted here, show that the auditory cortex shows plastic changes throughout life. Those that occur during maturation are typically considered the most profound and long lasting. In that case plasticity is beneficial as it allows adaptation to behaviorally important sound and adapts easily to changes induced by deafness and subsequent application of hearing aids or cochlear implants. In children as well as adults, changes in cortical representation of frequency can occur following hearing loss, but may be accompanied by unpleasant side effects such as tinnitus. Long exposure to a spectrally enhanced acoustic environment of moderate sound level that does not cause hearing loss paradoxically also results in pronounced changes in the cortical tonotopic maps. These changes are very similar to those following noise trauma. This review provides evidence that in adults, long-lasting plastic changes in auditory cortex occur even in the absence of behaviorally relevant acoustic stimulation. However, in children, the long lasting absence of auditory stimulation arrests cortical development.     

Bimodal benefits of cochlear implant and hearing aid (on the non-implanted ear): a pilot study to develop a protocol and a test battery

ABSTRACT This is a pilot study that aims (1) to help design a protocol for fitting and optimizing cochlear implants and hearing aids, (2) to help design a test battery that can help monitor children's progress and (3) to assess the benefit of using a cochlear implant with a contralateral hearing aid. Seven children between the ages of seven and 15 years completed the study. None of them had worn a contralateral hearing aid (HA) since cochlear implantation (five to seven years after implantation). The Listening Inventory for Education (LIFE), Life Situation Questionnaire (LSQ), and Client Orientated Scale of Improvement for Children (COSI-C) questionnaires together with subject's feedback were used as subjective measures, and speech perception tests - the City of New York (sentences list) (CUNY) and Bamford-Kowal-Bench (sentences list) (BKB) depending on child's speech perception skills - in quiet and in noise were used as objective measures. The results showed mixed subjective feedback, even though objectively all children improved their speech perception scores when wearing cochlear implants and hearing aids. The COSI-C proved to be the most successful tool to collect feedback from parents.     

Guidelines (short version) of the French Society of Otorhinolaryngology (SFORL) on pediatric cochlear implant indications

ObjectivesThe authors present the guidelines of the French Society of Otorhinolaryngology – Head and Neck Surgery (Société française d’oto-rhino-laryngologie et de chirurgie de la face et du cou – SFORL) on the indications for cochlear implantation in children.MethodsA multidisciplinary work group was entrusted with a review of the scientific literature on the above topic. Guidelines were drawn up, based on the articles retrieved and the group members’ individual experience. They were then read over by an editorial group independent of the work group. The guidelines were graded as A, B, C or expert opinion, by decreasing level of evidence.ResultsThe SFORL recommends that children with bilateral severe/profound hearing loss be offered bilateral cochlear implantation, with surgery before 12 months of age. In sequential bilateral cochlear implantation in children with severe/profound hearing loss, it is recommended to reduce the interval between the two implants, preferably to less than 18 months. The SFORL recommends encouraging children with unilateral cochlear implants to wear contralateral hearing aids when residual hearing is present, and recommends assessing perception with hearing-in-noise tests. It is recommended that the surgical technique should try to preserve the residual functional structures of the inner ear as much as possible.     

Children with hearing impairment--living with cochlear implants or hearing aids

Objective

The aim of this study was to enhance knowledge about the life circumstances of children with cochlear implants or hearing aids, regarding daily functioning and attitude to the impairment.

Methods

Data were obtained from 36 children with cochlear implants and 38 children with hearing aids via study-specific questionnaires with fixed answer alternatives. The questions covered (1) usage of aids and related factors, (2) hearing in different everyday situations, (3) thoughts about the children's own hearing and others’ attitudes to it, and (4) choice of language. The data were analyzed using SPSS, and presented via the theoretical frame of the International Classification of Functioning, Disability and Health, Child and Youth version (ICF-CY).

Results

Children with CI and HA functioned equally well in daily life, but there were also certain differences. Symptoms from neck and shoulders were more common among children with hearing aids than among children with cochlear implants (p < .001). Children with hearing aids used their aids significantly less often than those with cochlear implants (p < .001). The participation variables showed that children with hearing aids had significantly more hearing problems in team sports (p = .033) and outdoor activities (p = .019), in comparison to children with cochlear implants. The two groups had similar thoughts regarding their own hearing, mostly considering it not to be a problem. They also did not generally think that other people found their hearing to be a problem.

Conclusions

Children with cochlear implants and children with hearing aids have, in some aspects, equally good functioning in everyday life situations. However, certain differences were found in dimensions of functioning, regarding neck and shoulder pain, usage of aids and sign language, and hearing problems in some activities.