Cochlear implants in children

Cochlear implants are no longer considered new or experimental technology. Difficulty in evaluating the degree of hearing loss and response to traditional forms of amplification in young children makes pediatric cochlear implant candidacy a complex issue. Cochlear implantation and, in particular, pediatric cochlear implantation, requires a team commitment with contributions from surgeons, audiologists, speech pathologists, psychologists, and special educators. Elements discussed include assessment and candidacy issues, surgical technique, elements of a cochlear implant team, outcome assessment, and potential complications. The decision to perform pediatric cochlear implantation should not be undertaken without serious consideration to the enormous commitment required in both financial and personnel terms.     

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

OBJECTIVE: The purpose of this study was to evaluate the postoperative performance of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant with a view toward expanding the selection criteria for cochlear implant candidacy to include children who derive minimal benefit from amplification. DESIGN: Pre- and postoperative performance of two groups of children were compared. Group 1 consisted of 12 children who demonstrated some open-set speech recognition skills before receiving a Nucleus multichannel cochlear implant (Borderline group). Group 2 consisted of 12 children who demonstrated no open-set speech recognition skills before implantation with a Nucleus device (Traditional group). In all children, candidacy was determined based on preimplant binaural aided performance. For most subjects, the poorer ear was selected for implantation. Mean pre- and postoperative speech recognition scores of the Borderline subjects were compared to determine the benefit provided by their cochlear implants. Secondly, matched-pair analyses were used to compare the mean speech recognition scores obtained by the Borderline and Traditional subjects. RESULTS: The scores of the Borderline group improved significantly on five of six speech recognition measures when 6 mo postoperative scores obtained with the implant were compared with preoperative test scores obtained with hearing aids. By the 12 mo postoperative interval, the scores of the Borderline group had improved significantly (p < 0.05) on all six measures. In contrast, scores obtained by the Traditional group had improved significantly on three of six measures at both the 6 and 12 mo postoperative intervals. Comparison of postoperative test scores revealed that the Borderline group scored significantly higher than the Traditional group on three of six measures at the 6 mo test interval and on six of six measures at the 12 mo test interval (p < 0.05). CONCLUSIONS: The findings of this study indicate that both groups derive significant benefit from their cochlear implants. Although the mean preoperative audiograms for the implanted ears did not differ significantly for the two groups of subjects, members of the Borderline group exhibited significantly better speech recognition skills than the Traditional group during the first year after implantation. These findings suggest that the increased auditory experience of the Borderline subjects positively influenced their performance with a cochlear implant. The authors advocate that the selection criteria used to determine pediatric cochlear implant candidacy be broadened to include consideration of children who demonstrate minimal open-set speech recognition skills.     

Cochlear implantation: a review of the literature and the Nijmegen results

The field of cochlear implantation is developing rapidly. In subjects with bilateral profound deafness who gain no benefit from conventional hearing aids the aim of cochlear implantation is to provide a means for them to receive auditory sensations. Throughout the world, most cochlear implant centres are still continuing their research efforts to improve the results with this technique. Although it is still difficult to predict how an individual will perform with a cochlear implant, the success of cochlear implantation can no longer be denied. In this paper, we review some recent papers and reports, and the results of the various Nijmegen cochlear implant studies. Data about subject selection, examinations, surgery and the outcome are discussed. Our results were in good agreement with those of other authors. It can be concluded once again that cochlear implantation is an effective treatment for postlingually deaf adults and children, and for prelingually (congenital or acquired) deaf children with profound bilateral sensorineural deafness.     

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Cochlear implants have been very successful in restoring partial hearing to profoundly deaf people. Many individuals with implants are now able to communicate and understand speech without lip-reading, and some are able to talk over the phone. Children with implants can develop spoken-language skills and attend normal schools (i.e., schools with normal-hearing children). The greatest benefits with cochlear implantation have occurred in patients who (1) acquired speech and language before their hearing loss, and (2) have shorter duration of deafness. Gradual, but steady, improvements in speech production and speech perception have also occurred in prelingually deafened adults or children.     

Predictive factors for speech perception in patients with cochlear implant

Cochlear implant therapy is an epoch-making advance in artificial sensory organ transplants, but the positive effects on speech perception vary. Quantification theory type I, a multivariate analysis, was used to determine predictive factors for speech perception in patients with cochlear implants. Fifty-one postlingual deaf adults (18 male and 33 female, mean age, 53.4, mean duration of deafness, 8.6 years) were tested for speech perception three or more months after a Nucleus 22 channels cochlear implant. The cause of deafness in nine patients was labyrinthitis, ototoxicity in five, meningitis in three and unknown in the remaining 34. Speech perception was measured by vowel, consonant and word recognition using a live voice, and monosyllable, word and sentence recognition using a videodisc. All tests were administered in a sound only condition. Results of the univariate analysis indicated that age at implantation was correlated with monosyllable recognition, and duration of deafness was correlated with live voice word recognition. Residual hearing and coding strategy were both correlated with all outcome measures. The multivariate analysis revealed that coding strategy, duration of deafness, residual hearing and the number of electrodes were significant predictors of live voice word recognition in that order.     

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INTRODUCTIONS: Cochlear implants are used for the rehabilitation of bilaterally deaf patients. Due to the improvements in speech processing they might be also useful for patients with residual hearing and some speech understanding. METHODS: Pre- and postoperative speech understanding scores in 26 patients receiving implants were evaluated in a retrospective study. RESULTS: The preoperative pure-tone threshold in the implanted ear was between 80 and 115 dB in the frequency range of 500 to 2000 Hz. On the contralateral side the mean threshold was 10 dB better. The mean score for the number test was 11.3%, for the monosyllables below 5%. Postoperatively speech understanding improved significantly up to 97% for numbers and 48% for monosyllables (tested with the Freiburger Speech Test). Cochlear implantation also benefits patients with residual hearing and some speech understanding with hearing aids under optimum conditions. The speech understanding scores must be below certain limits. General selection criteria cannot yet be specified. The individual decision must be based upon several criteria, especially the speech understanding scores in quiet and noise under optimum conditions. A prospective study is needed to develop generally applicable criteria.     

Cochlear implantation in children with inner ear malformations

We performed a case study and intervention study, with follow-up of 1 to 5 years, in 4 children with inner ear malformations who underwent implantation of a multichannel cochlear implant (Nucleus, Cochlear Corporation) at ages 3 to 12 years. Malformations included a common cavity deformity, 2 incomplete partitions, and 1 case of isolated bilateral vestibular aqueduct enlargement. One child had a single-channel implant placed at 3 years of age, and this was exchanged for a 22-channel implant at age 9. One child had her implant placed at age 4.5 years, but due to complications from a cerebrospinal fluid (CSF) leak had the initial implant removed and replaced at age 5 years during repair of the CSF leak. Intraoperative findings included a CSF leak at the time of surgery in 3 patients. One patient contracted bacterial meningitis 7 months postimplantation that was thought to be secondary to acute otitis media in the unoperated ear. Bilateral CSF leaks were noted in the middle ear by a lumbar puncture radionuclide and fluorescein dye study. Successful repair of the CSF leaks and reimplantation of the cochlear implant was carried out in this patient. Mapping and programming of the implant was found to be challenging in each of these patients. All patients demonstrated improved performance after implantation. Two patients demonstrated some open-set speech perception. One patient demonstrates improved use of temporal cues in a structured closed set. One patient has achieved no significant speech recognition at this time, but does have improved sound detection and awareness. Cochlear implantation in children with congenital inner ear abnormalities can be a successful method of rehabilitation. It should be recognized that the postoperative speech perception results may be highly variable among patients, and that intraoperative complications may occur.     

Cochlear implants in children

Cochlear implants allow the rehabilitation of children with severe to profound hearing loss. They are beneficial for not only postlingual children with hearing loss but also for children with congenital or prelingual hearing loss. Issues regarding cochlear implant candidacy and surgery are discussed. The results of cochlear implants in children and the complications related to cochlear implant surgery in children are reviewed.     

Implant cochléaire et développement des échanges conversationnels.

Most researches conducted in the field of postimplant assessment have focused on the restoration of perceptual capabilities and the development of verbal language. In contrast, only very few studies have examined the impact of a cochlear implantation on children's overall development and, in particular, on their conversational language abilities. However, some previous works on the preverbal development revealed the recurrent difficulties experienced by deaf children in acquiring knowledge of social rules and social skills relative to speech activities. In children with profound bilateral deafness, a conventional hearing aid is not enough to provide sufficiently relevant information for a satisfactory development of oral communication. In such situations, the most suitable way of improving hearing is the use of a cochlear implant. The authors therefore hypothesized that access to oral perception will not only improve implanted children's social skills, but will also increase their rate of participation and the use of verbal language in their interaction with a familiar adult (mother or father). Their communication skills profile would resemble that of younger normal hearing children. Using conversational samples from a video-filming protocol at specific intervals, the authors monitored the development of communication skills in a group of 20 prelingually, profoundly deaf children (mean age: 3.7 years). Results corroborated our hypothesis. They indicated that children using cochlear implants increased their overall performance in communication skills, quantitatively and qualitatively speaking, even at the first year postimplantation stage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deafness in childhood: 3. Cochlear implants: who, why and what are the results?

Some profound or totally deaf children cannot benefit from a hearing aid. In some cases a cochlear implant may be successful. The system compromises a small cable implanted into the inner ear, and externally-worn devices to collect and transmit the sounds to the ear. The cable consists of electrodes that respond to different frequencies of speech, imitating the action of the inner ear. It is not possible to predict the outcome in individual cases. At best, the child may subsequently be able to speak fluently and hear without lip-reading. At least, the child should be able to hear some background noise such as traffic, and be able to improve his or her lip-reading skills. It may take up to a year before improvements begin to show. The implant is intended to be permanent. Cochlear implants are still at a relatively early stage of development. Progress is cautious but the results so far are very encouraging. The entry gate is widening and the number of children being accepted for treatment is increasing.     

Positron emission tomography of auditory sensation in deaf patients and patients with cochlear implants

The present study investigated the function of the auditory cortices in severely hearing-impaired or deaf patients and cochlear implant patients before and after auditory stimulation. Positron emission computed tomography (PET), which can detect brain activity by providing quantitative measurements of the metabolic rates of oxygen and glucose, was used. In patients with residual hearing, the activity of the auditory cortex measured by PET was almost normal. Among the totally deaf patients, the longer the duration of deafness, the lower the brain activity in the auditory cortex measured by PET. Patients who had been deaf for a long period showed remarkably reduced metabolic rates in the auditory cortices. However, following implantation of the cochlear device, the metabolic activity returned to near-normal levels. These findings suggest that activation of the speech comprehension mechanism of the higher brain system can be initiated by sound signals from the implant devices.     

Afferent projection patterns in the auditory brainstem in normal and congenitally deaf white cats

Cochlear implantation in congenitally deaf children is developing to a successful medical tool. Little is known, however, on morphology and pathophysiology of the central auditory system in these auditory deprived children. One form of congenital hearing loss, that seen in the deaf white cat, was investigated to see if there are differences in the afferent pathways from the cochlear nuclei to the inferior colliculus. The retrogradely transported fluorescent tracer diamidino yellow (DY) was injected into different parts of the central nucleus of the inferior colliculus (ICC) of normal cats and deaf white cats. It was found that the main afferent projection patterns in deaf white cats were unchanged in spite of congenital auditory deprivation; minor differences were seen.     

Audition and visual attention: the developmental trajectory in deaf and hearing populations

This study examined the development of visual attention in 5- to 13-year-olds who differed in their access to sound. Hearing children, deaf children with cochlear implants, and deaf children without implants participated in a task in which they were to respond to some visual signals and not others. The results of Experiment I indicated that the timing of developmental changes in visual selective attention was similar for all 3 groups, occurring around 8 years. The magnitude of age-related change differed among groups; hearing children and older deaf children using a cochlear implant reached higher levels of performance with age than did deaf children without enhanced access to sound. The results of Experiment 2 suggest that the developmental differences between deaf children with and without cochlear implants begin prior to 8 years and may be related to their use of environmental sounds to organize visual attention.     

Usefulness of ictal and interictal 99mTc ethyl cysteinate dimer single photon emission computed tomography in patients with refractory partial epilepsy

OBJECTIVE: The aim was to investigate the feasibility of recording the electrical auditory brain stem response (EABR) evoked by electrical stimulation at the promontory (Prom-EABR) as a tool to assist selection of the ear for cochlear implantation in young children. STUDY DESIGN: The study group consisted of young children for whom the decision to proceed with implantation with the Nucleus mini 22-channel cochlear implant (Cochlear (UK) Ltd., London, UK) had already been made. SETTING: The Prom-EABR was recorded after the children had been anesthetised, but before the start of surgery. PATIENTS: A group of 25 children (11 boys and 14 girls), whose age at implantation ranged from 2 years 11 months to 6 years 8 months (mean age, 4 years 5 months), were investigated. INTERVENTION: Recordings of the Prom-EABR were used to determine which ear would receive the cochlear implant, providing there were no preexisting contraindications regarding selection of the ear. MAIN OUTCOME MEASURE: It has been suggested from earlier studies that the characteristics of the amplitude input/output (I/O) function of the EABR are related to neuronal survival. If the ear with the "better" I/O function is chosen for implantation, it might be expected that these children will perform better on average than those in whom the ear has been selected at random. RESULTS: Reliable recordings of the Prom-EABR were achieved in 40 ears (80%) of the 50 ears in the study. In 20 of the 25 children the technique was actively employed for selection of the ear for implantation. CONCLUSIONS: Recording of the Prom-EABR in the operating theater is a viable technique. Future analysis of long-term outcome measures of performance with the implant will confirm or dispute the benefit of ear selection using the Prom-EABR.     

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

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

A modification of play audiometry to assess speech discrimination ability in severe-profoundly deaf 2- to 4-year-old children

OBJECTIVE: The aim was to develop an assessment procedure that was independent of language and speech production ability, to test speech feature discrimination in severe-profoundly deaf children 2 to 4 yr of age. DESIGN: The procedure being trialed was adapted from existing procedures. The child was required to respond with a game-like motor response to a "change" in a speech stimulus that was being presented repeatedly through a speaker. The change occurred at randomly determined times, and false alarm responses were measured during the waiting periods (while the child waited for the change). Two- to four-yr-old normally hearing children and hearing-impaired children using hearing aids and a group of 4-yr-old hearing-impaired children using cochlear implants were assessed on the task. RESULTS: More than 82% of the 3- and 4-yr-old normally hearing and hearing-impaired children were able to complete the testing for the eight speech sound contrasts within three 20 minute sessions. Fifty percent of the 2-yr-old normally hearing and hearing-impaired children were able to condition and complete the task. All of the normally hearing children who completed the task successfully discriminated all speech sound contrasts. The performance of the hearing-impaired children using hearing aids was influenced by the degree of hearing loss and the type of speech contrast being tested. Similarly, the average performance of the children using cochlear implants was better for easier contrasts such as /ba/bi/ with contrasting vowel formant cues. CONCLUSIONS: This procedure has potential for use as a reliable clinical and research tool for assessing the development of auditory discrimination ability in 2- to 4-yr-old severe-profoundly deaf children.     

Criteria and procedures for selection of children with acquired or congenital deafness for cochlear implants in Europe

The Nucleus Mini System 22 cochlear implant has been implanted in over 2,000 children worldwide. Selection criteria have evolved similar to that for adults since implantation in children began in 1985. The appropriate selection of children for implantation is made by a professional pediatric team which considers audiological and non-audiological issues in determining if the child is a cochlear implant candidate. The main philosophy is to establish if the child has the potential to benefit from a cochlear implant.     

Results of cochlear implantation in patients with severe to profound hearing loss--implications for patient selection

In patients with some residual hearing and minor benefit from conventional hearing aids, the benefits of cochlear implantation have to be weighed carefully against eventual adverse effects. In this study, pre- and post-operative thresholds as well as functional results after cochlear implantation are reported; 17 of 44 implanted adults had residual hearing pre-operatively (mean threshold(250 to 4000 Hz): 106 dB HL) in the implanted ear. Residual hearing in the implanted ear could not, in general, be preserved post-operatively. Seventeen of 44 implanted children had some amount of residual hearing in the implanted ear pre-operatively (implanted ear: 114 dB HL; contralateral ear: 109.9 dB HL; mean thresholds(250 to 4000 Hz))). Contrary to the results in adults, residual hearing in the implanted ear remained statistically unchanged. Hearing in the contralateral ear increased significantly from 109.9 to 101.9 dB HL post-operatively. This increase was mainly attributed to maturation of the central auditory pathway. In adults with residual hearing, the monosyllable word recognition scores increased significantly from 9 per cent pre-operatively to 42 per cent post-operatively. Children with residual hearing tended to perform better on speech-related test material compared to children without prior auditory experience. Cochlear implantation is indicated in adults and children with residual hearing and minor benefit from conventional amplification. The contralateral ear in children should be considered for additional acoustical stimulation.     

Communication between deaf children and their hearing mothers: the role of language, gesture, and vocalizations

In the present longitudinal study, 20 deaf and 20 hearing children were observed during free play with their hearing mothers when the children were 22 months and 3 years of age. Compared to hearing children, deaf children were severely language delayed, with deaf 3-year-olds using less language (speech or sign) than hearing 22-month-olds. Deaf children communicated primarily through nonlinguistic vocalizations, with increasing use of gesture from 22 months to 3 years of age. Although mothers of deaf children used more visual communication than mothers of hearing children, they still primarily communicated through speech. In addition, deaf children did not visually attend to much of their mothers' communication. Therefore, deaf children received much less communication than hearing children. These results suggest that intervention efforts should be focused on increasing the quantity of perceived linguistic input by the child.     

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Cochlear implantation has evolved from its experimental state into a safe and effective therapy for the treatment of profound deafness. Although not applicable to all patients, it offers an alternative to a life in silence. In particular, in early detected and treated deafness in childhood inner ear prostheses have enabled affected persons to be integrated into the world of sound. In addition to the significant impact that therapy has on the life of the individual, there is a social and cultural consequence for society. This is epitomized in the criticism by the deaf community that has resulted in the total rejection of cochlear implants. A critical analysis reveals different personal images prevailing in the deaf community. Knowledge of these differences and their relevance is important for all clinicians involved in counselling a cochlear implant candidate.