Determinants of speech perception in children after cochlear implantation

An exploration of demographic bias in a questionnaire survey of hearing-impaired children: implications for comparisons of children with and without cochlear implants

OBJECTIVES

Responders to questionnaire surveys, who are self-selecting, are generally accepted to be unrepresentative of the total available population, at least in demographic terms. Since demographic and other variables are known to be predictive of outcome, it is important to understand the extent of that unrepresentativeness when using survey data to report comparisons of outcome. This paper aims (i) to evaluate the extent to which a sample of hearing-impaired children surveyed by postal questionnaire was representative of the population of hearing-impaired children in the United Kingdom (UK), and (ii) to identify demographic differences between children with and without cochlear implants.

METHODS

Data from a previously reported total ascertainment of hearing-impaired children in the UK which identified 17,160 with permanent bilateral hearing impairment >40 dB HL were compared with data collected by postal questionnaire for a sample of 3224 children, including 527 with cochlear implants.

RESULTS

The sampled children were similar to the ascertained population in gender, age at onset of hearing impairment, and number of additional disabilities, but came from more recent birth cohorts and from more affluent families. Compared with profoundly impaired non-implanted children, implanted children had greater degrees of hearing loss, fewer additional disabilities, a later age of onset, were younger, came from more affluent families, were more likely to use spoken language at home, and to be taught using spoken language only.

CONCLUSIONS

Comparisons of outcomes and generalisation of results require adjustment for relevant variables to avoid confounding estimates of the effectiveness of interventions including 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.

Does cause of deafness influence outcome after cochlear implantation in children?

OBJECTIVES

The objective of this study was to evaluate long-term speech perception abilities of comparable groups of postmeningitic and congenitally deaf children after cochlear implantation.

METHODS

This prospective longitudinal study comprised 46 postmeningitic deaf children and 83 congenitally deaf children with age at implantation of < or = 5.6 years. Both groups were comparable with respect to educational setting and mode of communication and included children with additional disabilities.

RESULTS

Both postmeningitic and congenitally deaf children showed significant progress after implantation. Most (73% and 77%, respectively) could understand conversation without lip-reading or use the telephone with a known speaker 5 years after implantation, whereas none could do so before implantation. At the same interval, the postmeningitic and congenitally deaf children scored a mean open-set speech perception score of 47 (range: 0-91) and 46 (range: 0-107) words per minute, respectively, on connected discourse tracking. The respective mean scores at the 3-year interval were 22 and 29 correct words per minute, respectively. None of these children could score a single correct word per minute before implantation. The progress in both groups was statistically significant. When the 2 groups were compared, there was no statistically significant difference.

CONCLUSION

Postmeningitic and congenitally deaf children showed significant improvement in their auditory receptive abilities at the 3- and 5-year intervals after cochlear implantation. There was no statistically significant difference between the outcomes of the 2 groups, suggesting that, provided that children receive an implant early, cause of deafness has little influence on outcome. Although the prevalence of other disabilities was similar in both groups, for individual children, their presence may have profound impact. The study supports the concept of implantation early in life, irrespective of the cause of deafness.

Cochlear implantation in obstructed cochleas: the effect of the degree of obstruction on the number of activated electrodes and the amount of postoperative speech perception

OBJECTIVE

With cochlear implantation, insertion of the electrodes can be hampered by cochlear obstructions. The aim of this study was to investigate the effects of these obstructions on the number of activated electrodes and postoperative speech perception.

STUDY DESIGN AND SETTING

Retrospective analysis of the operation reports and CT-scans of patients who underwent cochlear implantation, at the Department of Otorhinolaryngology of the University Medical Center of Utrecht (n = 295).

PATIENTS AND INTERVENTIONS

Fifty patients with a certain degree of cochlear obstruction were included. Based on the surgical intervention to overcome these obstructions they were subdivided into first-, second- and third degree obstructions. The number of implanted and activated electrodes was determined.

MAIN OUTCOME MEASURES

Three different speech perception tests after 12 months of cochlear implant use.

RESULTS

The number of activated electrodes significantly diminished with increasing obstruction degree (P < 0.01). This was caused by a lower amount of implanted electrodes combined with a higher amount of switched off electrodes. With a higher degree of obstruction the amount of postoperative speech perception decreased significantly (P < 0.01). This is partly explained by the lower number of activated electrodes and partly explained by the fact that a higher obstructions degree correlates with a higher degree of (retro-) cochlear pathology. Significantly more electrodes can be inserted into the severely obstructed cochlea using a Double Array Cochlear Implant.

CONCLUSION

Cochlear obstructions pose a surgical threat and negatively influence the postoperative speech perception results. Fortunately, due to surgical techniques, first and second degree obstructed cochleas can often be bypassed. Implanting of a Double Array implant brightens the prospects of patients with third (severe) degree obstructed cochleas.

Cortical Activity at Rest Predicts Cochlear Implantation Outcome

The functional status of central neural pathways, in particular their susceptibility to plasticity and functional reorganization, may influence speech performance of deaf cochlear implant users. In this paper, we sought to determine how brain metabolic activity measured before implantation relates to cochlear implantation outcome, that is, speech perception. In 22 prelingually deaf children between 1 and 11 years, we correlated preoperative glucose metabolism as measured by F-18 fluorodeoxyglucose positron emission tomography with individual speech perception performance assessed 3 years after implantation, while factoring out the confounding effect of age at implantation. Whereas age at implantation was positively correlated with increased activity in the right superior temporal gyrus, speech scores were selectively associated with enhanced metabolic activity in the left prefrontal cortex and decreased metabolic activity in right Heschl's gyrus and in the posterior superior temporal sulcus. These results reinforce the notion that implantation should be performed as early as possible to prevent cross-modal takeover of auditory regions and suggest that rehabilitation strategies may be more efficient if they capitalize on general cognitive functions instead of only targeting specialized circuits dedicated to auditory and audiovisual pattern recognition.

A retrospective study of cochlear implant outcomes in children with residual hearing

Background

There has been increasing demand for the cochlear implantation of children who demonstrate some auditory capacity with conventional hearing aids. The purpose of this study was to examine speech recognition outcomes in a group of children who were regarded as borderline candidates for cochlear implantation as their residual hearing and/or auditory functioning levels exceeded typical audiologic candidacy criteria.

Methods

A retrospective chart review was undertaken at one Canadian cochlear implant centre to identify children implanted at age 4 or older with a pure-tone-average of 90 dB or better and speech recognition of 30% or greater. Pre-implant and post-implant open-set word and sentence test scores were analyzed.

Results

Eleven children of 195 paediatric cochlear implant recipients met the inclusion criteria for this study. Speech recognition results for the10 English-speaking children indicated significant gains in both open-set word and sentence understanding within the first 6 to 12 months of implant use. Seven of 9 children achieved 80% open-set sentence recognition within 12 months post-surgery.

Conclusion

Children with several years of experience using conventional amplification demonstrated rapid progress in auditory skills following cochlear implantation. These findings suggest that cochlear implantation may be an appropriate intervention for selected children with severe hearing losses and/or auditory capacity outside current candidacy criteria.

Evaluación del implante coclear como técnica de tratamiento de la hipoacusia profunda en pacientes pre y post locutivos

INTRODUCTION

These are the objectives planned for this study: 1. Evaluate the results from the communication point of view. 2. Evaluate the cochlear implant (CI) impact on the quality of life. 3. Evaluate medical complications and technical failures. 4. Assess direct and indirect costs generated during the phases of a cochlear implantation programme. 5. Determine which factors have a high impact on the clinical evolution and the financial cost.

MATERIALS AND METHOD

A population of 877 patients, postlingual and prelingual, adults and children, have been studied. They were treated in 5 Spanish centres with cochlear implant programmes. Audiometric tests and global questionnaires on life quality have been carried out. Medical and CI technology complications have also been computed. Direct and indirect economic costs of a cochlear implant have been calculated.

RESULTS

Postlocutive-implanted patients reached the 40 dB SPL threshold in the Pure Tone Audiometry, and this result was maintained during the 12-year evolution. In Vowels test, it evolved from a 30% on pre-stimulation to 80-90%, in Disyllables words test it evolved from a 10% to a 50-60%, and in CID Sentences test it evolved from an 18% to a 60-70%. In the prelocutive population, results were influenced by the child's age at implantation. The best results were obtained by the children who had been implanted earlier. Those implanted between 0 and 3 years old evolved in the Vowels test from 0% during pre-stimulation to 95%, from a 0% to a 90% in Disyllables words test and from a 0% to a 90-95% in CID Sentences test. Also, the speech acquisition and development of the pre-locutive population was also influenced by the implantation age. An 80% of postlocutive adult patients stated a mood and sociability improvement after the cochlear implantation. They did not show health changes in general nor relevant modifications in the attention they usually received from relatives and friends. Severe medical-surgical complications were registered for a 3.42% of the cases, a 7.06% of mild medical-surgical complications and a 3.07% of technical breakdowns in the internal components of the CI. Financial cost of implantation for a post-locutive adult oscillated between 36,912 Euro and 37,048 Euro, and between 37,689 Euro and 44,273 Euro for a pre-locutive child.

CONCLUSIONS

Cochlear implants clearly enhance communication skills of the implantees. Results obtained for the prelocutive implanted population justify the creation of hearing screening programmes in new-borns. Postlocutive implanted adults have expressed satisfaction for the results obtained. However, they did perceive some limitations in situations of unfavourable acoustic conditions. An analysis of direct and indirect costs related to a CI programme has been made. It may be useful to carry out reports on the cost-benefit ratio in this field. The low index of complications observed shows which cochlear implant treatment technique complies with the adequate safety margins. The factors influencing the most in the evolution are: duration of hearing deprivation, age at implantation, cochlear anatomy and functionality of the auditory pathway, patient's and relative's motivation, and the coexistence of other handicaps associated to hearing losses.

Speech perception with the ACE and the SPEAK speech coding strategies for children implanted with the Nucleus cochlear implant

OBJECTIVE

The aim of this study is to determine whether implanted children using the ACE speech coding strategy demonstrate superior performances compared to implanted children using the SPEAK speech coding strategy over time.

METHODS

Cochlear implanted children with prelinguistic sensorineural bilateral deafness of profound degree, using either the ACE or SPEAK coding strategy, were evaluated and compared. Both groups of children used one of the speech coding strategies continuously from the initial programming session and for a period of 2 years post-switch-on. One group comprised children who were retrospectively implanted and had received the SPEAK speech coding strategy (n=32) and the second group consisted of prospectively implanted children who received the ACE speech coding strategy (n=26). Both populations were homogenous as far as age of implantation, degree of hearing loss, anatomy of the cochlea, depth of electrode insertion, and educational and rehabilitative support provided. Children were assessed at 6, 12 and 24 months post switch-on via pure-tone audiometry and for speech perception tests. Children using the ACE speech coding strategy were additionally evaluated using the MAIS and MUSS language scales.

RESULTS

Satisfactory benefits in speech perception were demonstrated by both groups of implanted children. No significant difference between the mean pure tone thresholds was observed postoperatively between the groups. Two years post switch-on the group using the ACE speech coding strategy demonstrated superior results for vowel discrimination in comparison to children using the SPEAK coding strategy. No significant difference was observed between the groups for performance on discrimination of syllable patterns (ESP) or for disyllablic word recognition tests. Additionally, the group of ACE users demonstrated maximum performance on MAIS and MUSS scales, 2 years post switch-on.

CONCLUSIONS

The results clearly demonstrate significant benefit of cochlear implantation in prelinguistically deafened children for speech perception ability when using either the SPEAK or ACE speech coding strategies. Children using the ACE speech coding strategy demonstrate more rapid progress in improved speech perception ability initially, however 2 years post switch-on, no significant difference in performance on open-set speech recognition tests can be noted irrespective of the strategy in use.

Long-Term Functional Outcomes and Academic-Occupational Status in Implanted Children After 10 to 14 Years of Cochlear Implant Use

OBJECTIVES

To assess a group of consecutively implanted children over 10 years after implantation with regard to implant device use and function, speech perception, and speech intelligibility outcomes; and to document current academic or occupational status.

STUDY DESIGN

A prospective longitudinal study assessing device function, device use, speech perception, speech intelligibility, and academic/occupational status of implanted deaf children.

SETTING

Pediatric tertiary referral center for cochlear implantation.

METHODS

The auditory performance and speech intelligibility development of 30 profoundly deaf children were rated before cochlear implantation and at 5 and 10 years after implantation using the Categories of Auditory Performance and the Speech Intelligibility Rating. The academic and/or occupational status of the participants after 10 years of implant experience was documented. All children received a Nucleus multichannel cochlear implant between the ages of 2.5 and 11 years (mean age at implantation, 5.2 yr). Implant experience ranged from 10 to 14 years of use.

RESULTS

After 10 years of implant experience, 26 subjects (87%) reported that they always wore their device; 2 subjects (7%), frequently; and 1 subject (3%), occasionally. Only one child had discontinued use of his device. After 10 years of implant use, 26 (87%) of the children understood a conversation without lip reading and 18 (60%) used the telephone with a familiar speaker. Ten years after implantation, 23 (77%) of the subjects used speech intelligible to an average listener or a listener with little experience of a deaf person's speech. One-third to one-half of the implanted children continued to demonstrate improvements at 5 to 10 years of implant use. Of the 30 implanted children, 8 (26.7%) experienced nine device failures. The length of time from identification of the first faulty electrode to reimplant surgery ranged from 2 weeks to 5.5 years, as several failures were gradual or intermittent. However, all children were successfully reimplanted. At the end of the study (10-14 yr after implantation), 19 subjects were in secondary school for children aged 11 to 16 years: 6 were in mainstream schools, 7 were in specialist hearing-impaired units attached to a mainstream secondary school, and 6 were in schools for the deaf. Of the remaining 11 subjects, 4 were in college studying vocational subjects, 2 were in a university studying for a bachelor's degree, 3 were working full-time, 1 was working and going to a university part-time, and 1 was a full-time mother of two young children.

CONCLUSION

All but 1 of the 30 implanted children continue using their devices 10 to 14 years after implantation, showing significant progress in speech perception and production. Device failure was frequent, but successful reimplantation occurred in all cases. One-third to one-half of the implanted children in this study continued to demonstrate improvements at 5 to 10 years of implant use. All children are studying or working and are actively involved in their local communities. The results suggest that cochlear implantation provides long-term communication benefit to profoundly deaf children that does not plateau for some subjects even after reimplantation. This study further indicates that cochlear implant centers need the structure and funding to provide long-term support, counseling, audiologic follow-up, rehabilitation, and device monitoring to implanted children.

Newborn Hearing Screening: Effectiveness, Importance of High-Risk Factors, and Characteristics of Infants in the Neonatal Intensive Care Unit and Well-Baby Nursery

BACKGROUND

In contrast to the recommendations of the Joint Committee on Infant Hearing, neonatal hearing screening programs are still not universally available, and many countries implement elective screening in high-risk newborns.

OBJECTIVE

To assess the failure rates of neonates in hearing screening and the relative importance of risk factors for hearing impairment, both in neonatal intensive care units and in well-baby nursery neonates. The impact on cost-effectiveness is also evaluated.

SUBJECTS

In the current study, 25,288 newborns were assessed; 23,574 were full-term newborns in the well-baby nursery and 1,714 neonates were in neonatal intensive care units.

METHODS

All neonates had a general examination (including assessment for congenital anomalies and related history) and were assessed using transient evoked otoacoustic emissions. All newborns were older than 36 weeks at examination and thus had reliable transient evoked otoacoustic emissions.

RESULTS

From the 23,574 full-term neonates in the well-baby nursery, 23,123 (98.1%) passed the test and 451 failed (1.9%). Fifty-three of the 23,574 neonates (0.2%) had a risk factor for hearing impairment; 44 (83%) passed the test and 9 failed (17%). Family history of congenital hearing loss and congenital anomalies were the most frequent risk factors for hearing loss. From the 1,714 neonates in neonatal intensive care units, 1,590 (93%) passed the test and 124 failed (7%). Two hundred thirty-two of the 1,714 neonates (14%) had a risk factor for hearing impairment; 205 (88%) passed the test and 27 failed (12%). In neonatal intensive care unit neonates, toxic levels of ototoxic drugs, mechanical ventilation for more than 24 hours, prematurity, and low birth weight were the most frequent risk factors for hearing loss. Congenital anomalies/syndromes were the most important risk factors for failing screening in both the neonatal intensive care unit and the well-baby nursery, as they showed the highest risk of failing hearing screening. The second most important factor in neonatal intensive care unit newborns was low birth weight, and the third was prematurity in relation to the possibility of failing hearing screening.

CONCLUSION

The present study found 575 neonates failing hearing screening of 25,288 tested newborns (2.3%). The fact that 78% of newborns who failed hearing screening were in the well-baby nurseries further supports the necessity of universal hearing screening instead of selective screening in neonatal intensive care units, even with the obvious impact on cost-effectiveness. Even if limited funding lead to selective screening in neonatal intensive care units, this should not be applied to high-risk newborns but to all neonatal intensive care unit neonates. Continuous assessment of risk factors and the related possibility of failing hearing screening are of paramount importance in designing hearing screening programs and refining the respective criteria.

Normal hearing and language development in a deaf-born child

BACKGROUND

Congenital deafness leads to major problems in speech, language, education, and social integration. Neonatal hearing screening and cochlear implantation now allow early hearing restoration. This article reports on a prospective longitudinal study of the first infant ever who received two cochlear implants in the prelexical period of her life.

METHODS

The first deaf-born girl ever who received two implants at the ages of 5 and 15 months, respectively, was followed-up with repeated and detailed quantitative assessments from birth to 4 years of age. This consisted of 1) audiologic evaluation (audiometry, speech audiometry, and Categories of Auditory Performance score), 2) linguistic evaluation (monthly video analyses and tests of vocabulary, language skills, grammar, and intelligibility of the child's speech), and 3) descriptive assessment of the educational setting.

RESULTS

All results lie within the 95% confidence interval of hearing peers. The audiologic performance lies at or above average from age 2 years onward. The child started babbling at the normal age of 8 months. Her linguistic skills increased from low percentiles before age 2 to above average from age 2 for comprehension and from age 3 for production. The grammar and intelligibility of the child's speech increased from low percentiles to average at age 4. The girl entered preschool at the normal age of 2.5 years, and this with only very limited special assistance.

CONCLUSION

This case illustrates the fact that congenital deafness no longer has to lead to abnormal hearing and abnormal speech development. It opens the debate of the ethics of not implanting a deaf child in the first few months of life.

Preoperative differences of cerebral metabolism relate to the outcome of cochlear implants in congenitally deaf children

In congenitally deaf children, chronological age is generally accepted as a critical factor that affects successful rehabilitation following cochlear implantation (CI). However, a wide variance among patients is known to exist regardless of the age at CI [Sarant, J.Z., Blamey, P.J., Dowell, R.C., Clark, G.M., Gibson, W.P., 2001. Variation in speech perception scores among children with cochlear implants. Ear Hear. 22, 18-28]. In a previous study, we reported that prelingually deaf children in the age range 5-7 years at implantation showed greatest outcome variability [Oh S.H., Kim C.S., Kang E.J., Lee D.S., Lee H.J., Chang S.O., Ahn S.H., Hwang C.H., Park H.J., Koo J.W., 2003. Speech perception after cochlear implantation over a 4-year time period. Acta Otolaryngol. 123, 148-153]. Eleven children who underwent CI between the age of 5 and 7 1/2 years were subdivided into a good (above 65%: GOOD) and a poor (below 45%: POOR) group based on the performance in a speech perception test given 2 years after CI. The preoperative (18)F-FDG-PET (F-18 fluorodeoxyglucose positron emission tomography) images were compared between the two groups in order to examine if regional glucose metabolic difference preexisted before the CI surgery. In the GOOD group, metabolic activity was greater in diverse fronto-parietal regions compared to the POOR group. In the POOR group, the regions related to the ventral visual pathway showed greater metabolic activity relative to the GOOD group. These findings suggest that the deaf children who had developed greater executive and visuospatial functions subserved by the prefrontal and parietal cortices might be successful in auditory language learning after CI. On the contrary, greater dependency on the visual function subserved by the occipito-temporal region due to auditory deprivation may interfere with acquisition of auditory language after CI.

Speech perception results in children implanted with Clarion devices: Hi-Resolution and Standard Resolution modes

CONCLUSIONS

Formal testing showed that HiRes users seem to make significant use of acoustic information. Furthermore, from observations reported by experienced care-givers, for example, family, teachers and speech therapists, these children learn a lot from their surrounding environment. Incidental learning, which takes place when acquiring skills or knowledge through naturally occurring events, is a key become available to these deaf paediatric cochlear implant recipients.

OBJECTIVE

To compare speech perception skills in children with a Clarion cochlear implant using different speech coding strategies, such as continuous interleaved sampling (CIS), simultaneous analogue stimulation (SAS) and Hi-Resolution (HiRes).

MATERIAL AND METHODS

The study population comprised 40 children, 17 implanted with a Clarion Hi-Focus 1.2 and 23 with a Clarion CII. All children were pre-lingually deaf and differed in terms of age and cause of deafness. All children had undergone a trial (minimum 6 months) with hearing aids before implantation. Children implanted with a Clarion 1.2 were either CIS or SAS users [Standard Resolution mode (SRM) group]; children implanted with a Clarion CII were Hi-Resolution users [Hi-Resolution mode (HRM) group]. Findings were assessed according to-Erber's hierarchical model (detection, discrimination, identification, recognition and comprehension), making use of a battery of speech perception tests calibrated to the age of the child. Further information concerning use of the implant in everyday situations was obtained by means of the Meaningful Auditory Integration Scale (MAIS) questionnaire, which was administered to the parents. Tests were carried out prior to each fitting session, at switch-on and then at 3, 6, 9 and 12 months. Findings at pre-implantation and at 12 months follow-up were collected for both the SRM and HRM groups. Speech perception results were analysed for the SRM and HRM groups, independent of age at implantation, for five subgroups of children according to the paediatric test battery in use and for two subgroups of children, one < and one > 5 years of age.

RESULTS

Clarion-implanted children using the Hi-Resolution strategy can develop better speech perception skills at 12 months post-implantation compared to children fitted with the SAS or CIS strategy. SAS or CIS users implanted before the age of 5 years tend to achieve better results at 1 year follow-up than children implanted later. In contrast, in Hi-Resolution users, a trend towards better results for recognition and comprehension tasks was observed in children implanted after 5 years of age.

Changes of 2-deoxyglucose uptake in the rat auditory pathway after bilateral ablation of the cochlea

It has been reported that the area of decreased glucose metabolism in the FDG-PET of prelingually deaf children correlates significantly with speech performance after cochlear implantation. In this study, we undertook to confirm changes of glucose metabolism in the cerebral cortex using an animal model with age-matching groups to completely exclude the influence of age differences between the deaf and normal-hearing groups. The cochlea was ablated bilaterally at a postnatal 10-14 days in the deaf groups; 3-4 deaf and normal rats were included at each time point at 1, 2, 4 and 8 weeks and 7 months after ablation. After injecting 2-deoxyglucose intraperitoneally, digitalized autoradiographic images were obtained, and analyzed by using two different methods; 3-dimensional voxel-wise statistical analysis and conventional 2-dimensional densitometry. The hypometabolic area analyzed using 3-dimensional analysis and the differences of optical density between normal and deaf as determined by densitometry were widest and most prominent between 4 and 8 weeks after ablation. Differences were not significant before 2 weeks or after 7 months after ablation. This result shows that the hypometabolic area becomes prominent after a critical period and it decreases as the duration of deafness increases. We believe that cross-modal plasticity may be the mechanism of changes in glucose metabolism and that this result reinforced the usefulness of evaluating hypometabolic area using FDG-PET in deaf children.

Neural changes associated with speech learning in deaf children following cochlear implantation

Brain plasticity was investigated, which underlies the gaining of auditory sensory and/or auditory language in deaf children with an early onset deafness after cochlear implantation (CI) surgery. This study examined both the glucose metabolism of the brain and the auditory speech learning using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and the Central Institute of Deaf (CID) test, respectively, both before and after the CI surgery. In a within analysis comparing the pre-CI and the post-CI PET results, CI itself resulted in an increase in the glucose metabolism in the medial visual cortex, the bilateral thalamus, and the posterior cingulate. Compared with the normal hearing controls, the brain activity of the deaf children was greater in the medial visual cortex and bilateral occipito-parietal junctions after the CI. The better speech perception ability was associated with increases in activity in the higher visual areas such as middle occipito-temporal junction (hMT/V5) and posterior inferior temporal region (BA 21/37) in the left hemisphere and associated with decreases in activity in the right inferior parieto-dorsal prefrontal region. These findings suggest that the speech learning resulted in a greater demand of the visual and visuospatial processings subserved by the early visual cortex and parietal cortices. However, only those deaf children who successfully learned the auditory language after CI used more visual motion perception for mouth movement in the left hMT/V5 region and less somatosensory function in the right parieto-frontal region.

Separating contributions of hearing, lexical knowledge, and speech production to speech-perception scores in children with hearing impairments

Open-set word and sentence speech-perception test scores are commonly used as a measure of hearing abilities in children and adults using cochlear implants and/or hearing aids. These tests are usually presented auditorily with a verbal response. In the case of children, scores are typically lower and more variable than for adults with hearing impairments using similar devices. It is difficult to interpret children's speech-perception scores without considering the effects of lexical knowledge and speech-production abilities on their responses. This study postulated a simple mathematical model to describe the effects of hearing, lexical knowledge, and speech production on the perception test scores for monosyllabic words by children with impaired hearing. Thirty-three primary-school children with impaired hearing, fitted with hearing aids and/or cochlear implants, were evaluated using speech-perception, reading-aloud, speech-production, and language measures. These various measures were incorporated in the mathematical model, which revealed that performance in an open-set word-perception test in the auditory-alone mode is strongly dependent on residual hearing levels, lexical knowledge, and speech-production abilities. Further applications of the model provided an estimate of the effect of each component on the overall speech-perception score for each child.

Cochlear Implantation in Children Deafened by Cytomegalovirus: Speech Perception and Speech Intelligibility Outcomes

BACKGROUND

Concerns have been expressed with regard to suitability for cochlear implantation of children deafened by cytomegalovirus because of possible coexisting central disorders/learning difficulties. The aim of the current study was to assess speech perception and intelligibility of speech produced by children deafened by cytomegalovirus and compare their progress with that of congenitally deaf children after cochlear implantation.

METHODS

The study assessed 16 implanted children who were deafened by cytomegalovirus, using the Iowa Closed Sentence Test and Speech Intelligibility Rating. The results were compared with those of a group of 131 children who had undergone implantation who were congenitally deaf but did not have cytomegalovirus as the cause of deafness. The mean age at implantation was 3.9 years for the cytomegalovirus group (median, 3.5 years) and 4.1 years (median, 4 years) for the congenitally deaf children. They all received the Nucleus multichannel cochlear implant system. The follow-up period ranged from 1 to 5 years after implantation for both groups.

RESULTS

After cochlear implantation, the intelligibility of speech produced by children deafened by cytomegalovirus had a wide range, varying from unintelligible speech to connected speech intelligible to all listeners. Relative to the median score for the control group at the last evaluation interval, 3 of the 16 children with cytomegalovirus (19%) performed better, 8 children (50%) performed more poorly, and 5 (31%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to speech perception Iowa Sentence Test (Level B), relative to the median score for the control group at the last evaluation interval, 5 of the 16 children with cytomegalovirus (31%) performed better, 3 children (19%) performed more poorly, and 8 (50%) performed the same. The difference between the two groups was not statistically significant (p > 0.05). With regard to Level A and relative to the median score for the control group at the last evaluation interval, 1 of the 16 children with cytomegalovirus (6%) performed better, 6 children (38%) performed more poorly, and 9 (56%) performed the same. The difference between the two groups was statistically significant (p = 0.04).

CONCLUSION

The results of the current study showed that cytomegalovirus alone, as a cause of deafness, is not a contraindication for cochlear implantation. Parents should be informed about the wide range of linguistic outcomes after implantation and that these children may need more specific or intensive rehabilitation. Although additional problems are common and outcomes may, on average, be poorer, cochlear implantation can provide useful auditory input to these children. Further research is needed to identify factors associated with cytomegalovirus that may influence the outcomes.

Audiological performance after cochlear implantation in children with inner ear malformations

OBJECTIVES

To prove that cochlear implantation is a beneficial method of rehabilitation in deaf children with malformations of the inner ear.

DESIGN

The evaluation of auditory responses to speech (EARS) test battery was performed on the children in this study after an average implant use of 3 years.

RESULTS

Individual results of six children with inner ear anomalies receiving cochlear implants are presented in this study. Three of the patients showed an incomplete partition (Mondini dysplasia), one had a cochlear hypoplasia and two suffered from an intraoperative cerebrospinal fluid leak. The majority of the children in this study are successful implant users. Wherever possible, test scores are included and subjective case reports given.

CONCLUSIONS

Results are similar to those in children with normal cochleas, therefore inner ear malformations found in as many as 20% of patients with congenital sensorineural hearing loss are no contraindication for cochlear implantation. Nevertheless, factors influencing the success of implantation are multiple, including a thorough preoperative radiological examination, a well-performed surgery and an individually tailored postoperative rehabilitation programme.

Assessing candidate children for cochlear implantation with the Nottingham Children's Implant Profile (NChIP): the first 200 children

BACKGROUND/OBJECTIVE

Nottingham Children's Implant Profile (NChIP) is a profile designed to assess candidate children for cochlear implantation. It includes the demographic details of the children (chronological age and duration of deafness), medical and radiological conditions, the outcomes of audiological assessments, language and speech abilities, multiple handicaps or disabilities, family structure and support, educational environment, the availability of support services, expectations of the family and deaf child, cognitive abilities, and learning style. The aim of the present study is to present the NChIP data obtained on the first 200 children implanted in the same cochlear implant programme and evaluate NChIP's use in the selection phase of cochlear implantation.

PATIENTS

The study assessed 200 profoundly deaf children. Fifty-six children (28%) were deafened by meningitis, 132 (66%) were born deaf, and 12 (6%) were deafened from other causes (head injury, viral infection, progressive deafness).

RESULTS

Chronological age at the time of assessment (before implantation) was the most common factor of major concern (9% of the children studied) and the pre-implant language and speech abilities of the children was the most common factor of mild to moderate concern, affecting 63% of the children. The second most common factor of mild to moderate concern was duration of deafness (37%) and the third was the learning style of the children (33%). Availability of support services was the least factor of concern as 179 children (90%) did not have any problems in this area.

CONCLUSIONS

Earlier identification of deafness (by universal neonatal hearing screening programs) may reduce age at implantation and duration of deafness as areas of concern in the future. However, the pre-implant language and speech abilities of the candidate children, the gap between chronological and language age, and the learning style of children are now emerging as key areas of research in the field. NChIP was found to be a very useful casework tool in the initial evaluation of the deaf children promoting and enhancing interdisciplinary teamwork across the different professionals. NChIP was also used as part of the decision-making process by the cochlear implant programme professionals and as a counselling tool for the parents. Finally, NChIP has helped to identify those children and families who need additional support. In the case of recently established paediatric cochlear implant programmes it would be a 'neutral' yet sensitive way of promoting good interdisciplinary collaboration and also peer support within team discussions when selecting children for cochlear implantation.

Predicting speech perception outcomes following cochlear implantation using Nottingham children's implant profile (NChIP)

BACKGROUND/OBJECTIVE

Nottingham children's implant profile (NChIP) is a systematic framework to assess deaf children before implantation taking into account not only the well-known factors (age, duration of deafness) but also family and support services, expectations, children's cognitive abilities and learning style. The aim of the present paper is to assess the predictive value of the NChIP in the long-term outcomes of implanted children.

PATIENTS

This prospective and longitudinal study involved 51 profoundly deaf children, implanted within the same paediatric cochlear implant programme. All children were pre-lingually deaf with age at onset of deafness <2 years and age at implantation <6 years. Three and 4 years following implantation all children were assessed using two measures of speech perception. No child was lost to follow-up and no child was excluded from the study for any reason.

RESULTS

The most constant predictor of the outcomes was children's learning style explaining upto 29% of the variance. Other significant predictors of the outcome were shorter duration of deafness, young age at implantation and family structure/support.

CONCLUSIONS

Intrinsic factors in children and how well they communicate with their environment are of paramount importance to the outcome following implantation. The predictive value of NChIP has been demonstrated and the most important predictors of the outcome were children's learning style, short duration of deafness, young age at implantation, and family structure/support.

The ear and its malformations: strange beliefs and misconceptions

OBJECTIVE

To explore the strange beliefs and misconceptions related to the ear and its malformations, and how these have changed from ancient times until today.

METHODS

Ancient documents, journal articles, and history books were studied to research ancient and current beliefs and misconceptions with regard to the ear and its malformations.

RESULTS

The ear has been the centre of various beliefs and misconceptions through human history. Discoveries in the area of Assyria and Babylonia have revealed that the inhabitants of these countries not only had documented various congenital dysplasias of the ear but also they believed that these malformations had prophetical meaning and implied hereditary disorders. These observations and prophecies may very well have their origin to the 4th millennium BC. Egyptian and Greek-Roman medicine had suggested strange connections of the ear with close or remote parts of the human body and similar beliefs can be found through the later centuries. Hebrew and Greek-Byzantine conceptions of the perfect appearance that priests or kings should have, led to exclusion of people who had congenital ear malformations and even to mutilation (cutting off the ears) as a method of punishment.

CONCLUSION

The present study illustrates the wide variety and the long history of misconceptions related to children born with congenital malformations of the pinna and the external ear canal. These misconceptions may have led to a conscious and subconscious anxiety and pressure from parents and patients to ENT and plastic surgeons to correct the ear malformations as soon as possible in order to avoid psychological and social problems.

Influence of auditory deprivation upon the tonopic organization in the inferior colliculus: a Fos immunocytochemical study in the rat

The frequency organization in the inferior colliculus of neonatally-deafened rats was investigated using electrical stimulation of the cochlea and immunoreactivity for Fos as a marker of neuronal activity. An electrode implanted either at the base or at the apex of the right cochlea delivered a unique 45-min stimulation at two different level intensities and at two time points, i.e. either at 4 weeks or at 4 months. In 4-week-old rats stimulated at 5x threshold, a site-for-site organization was observed since basal or apical stimulation induced a strong labelling in the ventro-medial or in the dorsolateral part of the left inferior colliculus, respectively. In 4-month-old rats, stimulation of the base induced an extremely weak Fos labelling without any specific location in the left inferior colliculus while stimulation of the apex induced a diffuse labelling with two discrete bands being distinguishable in the left inferior colliculus. In 4-week-old rats stimulated at 15x threshold, basal stimulation elicited a diffuse Fos-like immunoreactivity in the left inferior colliculus while apical stimulation yielded a response restricted to the dorsal part of the left inferior colliculus. In 4-month-old rats, no response was detected in the left inferior colliculus after stimulation of the basal part of the cochlea. Stimulation of the apex could still induce a labelling in the dorsolateral left inferior colliculus. Thus, the inferior colliculus exhibits an adult-like tonotopic organization early on independently of any acoustic stimulation. Prolonged absence of auditory input dramatically alters this organization in the inferior colliculus, especially for high frequencies. From a clinical standpoint, these results could argue for early implantation in deaf children.

Using SNAP Dragons to monitor narrative abilities in young deaf children following cochlear implantation

OBJECTIVE

To assess the narrative abilities of young deaf children before cochlear implantation and 1 and 2 years following implantation, and to explore possible changes in the implanted children's preferred mode of communication in the narrative abilities task.

STUDY DESIGN

Prospective longitudinal study assessing the narrative abilities of young deaf children before and after cochlear implantation.

SETTING

Pediatric tertiary referral center for cochlear implantation.

PATIENTS AND METHODS

The narrative abilities of 35 young profoundly deaf children were assessed before implantation and 1 and 2 years following implantation using the Stories/Narratives Assessment Procedure. Children with age at implantation less than 6 years were included in the study (mean age at implantation was 3.5 years; range 1.4-5.9 years). All children were filled with the Nucleus multichannel cochlear implant system. With respect to their communication modes, they came from a wide range of backgrounds and all children were encouraged to use their preferred mode of communication during the narrative task.

RESULTS

The data showed that there was a statistically significant increase in narrative abilities across the three data points (P<0.001). Before receiving the implant, children were mostly in the pre-structural, receptive stages and could at most label or comment on the pictures (median narrative stage 2). By the 2-year interval, children were mostly using one or two categories or one complete episode with spontaneous retelling (median narrative stage 4). Although children were not pressured to use any particular communication mode, a shift to speech was found following implantation and this was statistically significant (P<0.001).

CONCLUSION

Young implanted deaf children showed a significant progress in their narrative abilities through time and a significant shift in the predominant mode of communication towards more speech orientated communication modes following cochlear implantation.

Variables affecting speech perception in postlingually deaf adults following cochlear implantation

OBJECTIVE

To evaluate the time span over which there is greatest improvement in postlingually deaf adults undergoing cochlear implantation. Additionally, to quantify potential patient and device factors that may predict the postoperative results.

MATERIAL AND METHODS

A longitudinal study was conducted. Numbers, monosyllables and sentence test results were collected for 66 cochlear implant subjects [Combi 40/40 +, n = 60; Clarion HF2, n = 2; Nucleus 24m/k, n = 4] at regular intervals for up to 6 years following cochlear implantation.

RESULTS

All patients showed a steady improvement over time on all tests. Progress during the first 12 months was statistically significant, with further improvements being recorded after the 12-month testing period. The duration of deafness and the number of electrodes (8 for the Combi 40, 12 for the Combi 40 + ) appeared to be weakly correlated with postoperative performance. Re-implantation after device failure had no negative effect on speech reception. Subjects who were "upgraded" from an analogue to a digital cochlear implant improved their test results almost twofold.

CONCLUSION

All the patients in our study gained substantial benefit from their cochlear implants. It is encouraging to note that the factors examined were not deemed to be relevant predictors of performance. Even long-term deaf subjects and re-implantees are able to achieve an excellent level of speech perception.

Aetiology of hearing loss and other related factors versus language outcome after cochlear implantation in children

OBJECTIVE

Cochlear implantation outcome in prelingually deafened children is highly variable. The objective of this study was to examine the relationship between the yearly improvements in speech and language scores after cochlear implantation in children, with the aetiology of the hearing loss and other related factors.

METHODS

We reviewed the case notes of children with early onset (0-2 years) of hearing loss, who were implanted in their first decade of life between 1992 and 2000 in Great Ormond Street Children Hospital. We assessed the relationship between the improvement of the receptive language and speech scores, on each year after implantation, with the aetiology of hearing loss and with the presence of additional medical problems.

RESULTS

Children with a syndromic diagnosis had lower speech and language improvement scores at years 4 and 5 after implantation than children with a hereditary-non syndromic or unknown diagnosis. Vision and vestibular problems were significant negative predictors for speech and language improvement scores. The disability score, i.e. an overall index of additional to the hearing loss problems, had a negative correlation with the speech and language improvement scores.

CONCLUSIONS

The presence of a syndromic diagnosis, vision or vestibular problems, and the overall level of additional to the hearing loss problems, may be negative prognostic indicators for speech and language improvement after implantation.

Assessment of auditory skills in 140 cochlear implant children using the EARS protocol

Auditory performance of cochlear implant (CI) children was assessed with the Listening Progress Profile (LiP) and the Monosyllabic-Trochee-Polysyllabic-Word Test (MTP) following the EARS protocol. Additionally, the 'initial drop' phenomenon, a recently reported decrease of auditory performance occurring immediately after first fitting, was investigated. Patients were 140 prelingually deafened children from various clinics and centers worldwide implanted with a MEDEL COMBI 40/40+. Analysis of LiP data showed a significant increase after 1 month of CI use compared to preoperative scores (p < 0.01). No initial decrease was observed with this test. Analysis of MTP data revealed a significant improvement of word recognition after 6 months (p < 0.01), with a significant temporary decrease after initial fitting (p < 0.01). With both tests, children's auditory skills improved up to 2 years. Amount of improvement was negatively correlated with age at implantation.

Speech perception after cochlear implantation over a 4-year time period

OBJECTIVE

To evaluate the long-term speech perception of cochlear implantees and to compare the developing auditory performance patterns of prelingual children and postlingual deaf adults.

MATERIAL AND METHODS

Twenty-nine prelingually deaf children and 17 postlingually deaf adults who had been followed up for 4 years were included in the study. Speech perception ability was assessed by means of vowel and consonant confusion tests and the Korean version of the Central Institute of Deafness (K-CID) test (performed without visual cues). The test results were analyzed at 3 and 6 months after implantation and then annually.

RESULTS

In the prelingually deaf children, the average results continuously improved over the 4-year period. In the postlingually deaf adults, the average results did not improve further after the first 2 years. Individuals with < 5 years of deafness had a faster rate of recovery of speech perception than those who had been deaf for > 5 years. The K-CID scores were negatively correlated with age at implantation for the prelingually deaf group and with the duration of deafness in the postlingually deaf group. Children fitted with implants at a younger age showed better speech perception ability than those fitted with implants at an older age. Interestingly, prelingually deaf children aged 5-7 years at implantation showed the widest variation in individual outcomes. Amongst this group of children with highly variable outcomes, the metabolic status of brain cortices determined by means of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was available for three patients. The individual with the widest hypometabolic area had the best speech perception ability.

CONCLUSION

The extent of hypometabolism as assessed by FDG-PET seemed to be one of the major factors predicting the outcome of cochlear implantation.

A parental questionnaire to evaluate children's Auditory Behavior in Everyday Life (ABEL)

The Auditory Behavior in Everyday Life (ABEL) questionnaire was developed to assess parental perceptions of their children's auditory behavior. The original 49-item questionnaire was intended to assess auditory communication, environmental awareness, functional independence, and social/ communication skills. Our goal was to capture some of the changes in children's everyday auditory behavior in a reliable and easily quantifiable manner. Parents of 28 children aged 4 to 14 years with varying degrees of hearing loss (mild-profound) completed the questionnaire. The results were used to examine the reliability and factor structure of the questionnaire. Eleven items had poor item-total correlations. After these items were removed, the questionnaire had an overall reliability of 0.94 (Cronbach's alpha), and three factors accounted for 20.5% of the variance in the data. In a pilot investigation of the ABEL to determine its appropriateness for children with cochlear implants, questionnaires were also given to a separate group of parents of seven children aged 3 to 12 years who were about to receive a cochlear implant. Questionnaire and speech perception results were obtained preimplant and at 6, 12, 18, 24, and 36 months. Complete (6 visits) or near-complete (4 visits) results were obtained for four children. There were significant improvements over time for both speech perception and questionnaire ratings and there was significant agreement between the two measures. Overall the results indicate excellent reliability and validity of the ABEL questionnaire. Our intent was to develop a simple, quick tool for parents to rate children's auditory skills in everyday life. A shorter questionnaire can be achieved by eliminating items with the poorest reliability and factor loadings. The resultant 24-item ABEL questionnaire has an excellent overall reliability of 0.95. The items fall within three factors, "Aural-oral," "Auditory Awareness," and "Social/Conversational Skills." Children's auditory behavior can be assessed using an overall rating or separately for the three factors. Further research is needed to evaluate this short version of the questionnaire in children wearing hearing aids and cochlear implants.

Minimal access surgery for pediatric cochlear implantation

OBJECTIVE

To develop a minimal access approach for pediatric cochlear implantation to improve the acceptability of the procedure for parents, children, and the wider community, and to reduce flap-related complications of the procedure.

STUDY DESIGN

Prospective evaluation of a new surgical technique.

METHOD

A new approach was developed through a short, oblique, straight postauricular incision without shaving any hair. It involved drilling the bony well for the implant inside a small subperiosteal pocket.

PATIENTS

Twenty-three consecutively implanted children with the Nucleus implanted system, whose median age was 3.2 years (mean 4.1 years, range 1.6-11.2 years.

RESULTS

The technique proved feasible in all the 23 children, and no major complications were encountered. Three instances of wound edema were observed early in the series; by minimizing tissue elevation and overzealous retraction, these complications were not encountered subsequently. The approach was warmly endorsed by parents, children, and caregivers, who greatly appreciated the minimal impact of the approach.

CONCLUSION

The proposed new approach is very well accepted by implanted children and their families, reduces the psychologic trauma of the intervention, and has less risks of flap complications.

Paediatric cochlear implantation: prosthetic hearing and language development

CONTEXT

Cochlear implantation offers hearing and vocational benefits to children and adults who lose their hearing after acquiring speech and language. But such implantations in prelingually deaf children are controversial, with concerns about diagnosis in very young children, safety, and durability. Implantation of children under age 2 years is potentially associated with higher surgical and anaesthesia risks, and with more challenging preoperative and postoperative management.

STARTING POINT

Although only a small number of children implanted before age 2 have sufficient maturity and implant experience to undergo adult-type speech recognition tests, surgical series show that these children may be implanted safely and that their subsequent speech perception is at least as good as children implanted at an older age. The Nottingham, UK, group recently reported on a consecutive sample of 12 children aged under 2 years at implantation (Arch Otolaryngol Head Neck Surg 2002; 128: 11-14). S S Hehar and colleagues show satisfactory perioperative and postoperative surgical outcomes. 2 years after the implantation, mean scores on the Listening Progress Profile had increased from 1 to 42. Median scores of Categories of Auditory Performance increased from 0 to 5. There were no significant differences compared with a historical control group of deaf children implanted at ages 3-5. WHERE NEXT? Early results from parental observation of auditory behaviours show that children who receive a cochlear implant at an early age perform at least as well as those implanted later. These data, combined with more rigorous speech recognition results in older children, merit a gradual reduction in the age of implantation, although the uncertainties inherent in audiometric assessment and measurement of hearing-aid benefit in infants must be borne in mind. Cochlear implants in prelingually deafened children permit improved development of speech reception, language acquisition, and reading comprehension.

A method for the direct electrical stimulation of the auditory system in deaf subjects: a functional magnetic resonance imaging study

PURPOSE

To develop a safe functional magnetic resonance imaging (fMRI) procedure for auditory assessment of deaf subjects.

MATERIALS AND METHODS

A gold-plated tungsten electrode has been developed which has zero magnetic susceptibility. Used with carbon leads and a carbon reference pad, it enables safe, distortion-free fMRI studies of deaf subjects following direct electrical stimulation of the acoustic nerve. Minor pickup of the radio frequency (RF) pulses by the electrode assembly is difficult to eliminate, and a SPARSE acquisition sequence is used to avoid any effects of unintentional auditory nerve stimulation.

RESULTS

The procedure is demonstrated in a deaf volunteer. Activation is observed in the contralateral but not the ipsilateral primary auditory cortex. This is in sharp contrast to studies of auditory processing in hearing subjects, but consistent with the small number of previous positron emission tomography (PET) and MR studies on adult deaf subjects.

CONCLUSION

The fMRI procedure is able to demonstrate whether the auditory pathway is fully intact, and may provide a useful method for preoperative assessment of candidates for cochlear implantation.

Receptive and expressive language skills of 106 children with a minimum of 2 years' experience in hearing with a cochlear implant

OBJECTIVE

The aim of the study was to assess the speech development of children with at least 2 years' hearing experience with a cochlear implant (CI).

METHODS

One hundred and six children were tested, all of whom had used the CI for at least 2 years. Receptive and expressive language development were tested using the scales of early communication skills for hearing-impaired children after Geers and Moog and the Reynell developmental language scales III. In addition, free-field audiometry was performed. Pre-postoperative measurements were compared statistically, and a linear regression analysis was carried out.

RESULTS

Clear improvements in the gain in functional hearing 2 years after receiving the CI as well as clear improvements in both speech perception and speech production were ascertained. All deviations were statistically highly significant (P<0.000). The receptive and expressive speech test results correlate positively to a great extent. The results of logistic regressive analysis indicate that the speech production measured depends decisively on age at implantation, age at time of test, speech production before implantation, and additional handicaps.

CONCLUSION

Based on the conception of the WHO, a statistically significant improvement of both impairment and disability can be confirmed. In the present study, the regression analysis established the age at implantation as the most important prognostic factor. While the percentage of children with good speech development is larger with early implanted children than with late implanted children, some of the children among the early implanted group show unsatisfactory speech development of unknown origin. Improvements in speech development are likely to be achieved when more children are diagnosed and implanted early. This finding urgently requires the introduction of a general newborn screening program. Thorough anamnesis and assessment during parent counseling of the manifold factors described are a prerequisite for the precise estimation of the difficulties to be met and the expected effectiveness of the implant in each individual case.

Performance of cochlear implant recipients with GJB2-related deafness

Congenital profound hearing loss affects 0.05-0.1% of children and has many causes, some of which are associated with cognitive delay. For prelingually-deafened cochlear implant recipients, the etiology of deafness is usually unknown. Mutations in GJB2 have been established as the most common cause of heritable deafness in the United States. In this report, we identify cochlear implant recipients with GJB2-related deafness and examine the performance of these individuals. Cochlear implant recipients received a battery of perceptive, cognitive, and reading tests. Neither subjects nor examiners knew the etiology of deafness in these individuals. The implant recipients were then examined for mutations in GJB2 using an allele-specific polymerase chain reaction assay, single-strand conformation polymorphism analysis, and direct sequencing. GJB2 mutations were the leading cause of congenital deafness among the cochlear implant recipients screened. Cochlear implant recipients with GJB2-related deafness read within one standard deviation of hearing controls better than other congenitally deaf cochlear implant recipients and non-cochlear implant recipients. Individuals with congenital deafness should be offered GJB2 screening. Positive results establish an etiologic diagnosis and provide prognostic, genetic, and therapeutic information. Effective rehabilitation for profoundly deaf individuals with GJB2-related deafness is possible through cochlear implantation.

The educational settings of profoundly deaf children with cochlear implants compared with age-matched peers with hearing aids: implications for management

The educational settings of 42 implanted profoundly deaf children 3 years after implantation were compared with the respective settings of 635 age-matched severely deaf and 511 profoundly deaf children with hearing aids. All implanted children received their implants before beginning school. The results revealed that 3 years after implantation. 38% (16 children) of the implanted profoundly deaf children attended mainstream schools, whereas 57% (24 children) were in a unit, or special class, in a mainstream school, and 5% (two children) were in schools for the deaf. With regard to the age-matched profoundly deaf children with hearing aids, 12% (63 children) attended mainstream schools, whereas 55% (281 children) were in a unit of a mainstream school, and 33% (167 children) were in schools for the deaf. In the group of age-matched severely deaf children, 38% (239 children) attended mainstream schools, whereas 51% (326 children) were in a unit of a mainstream school, and 11% (70 children) were in schools for the deaf. Statistical analysis revealed a highly significant difference between the educational placement of implanted children and hearing-aided profoundly deaf children (p<0.00001), whereas there was no statistically significant difference between implanted children and hearing-aided severely deaf children. In conclusion, implanted profoundly deaf children who have received their implants before beginning school have the same profile of educational placement as aided severely deaf children rather than aided profoundly deaf children of the same age in the UK. This is likely to have significant implications for the future management of profoundly deaf children and to influence future planning of educational support services.

The role of age in pediatric cochlear implantation

OBJECTIVE

To document progress, benefit and importance of age in paediatric cochlear implantation.

DESIGN

The EARS (Evaluation of Auditory Responses to Speech) test battery was performed on 33 prelingually deaf children at regular intervals up to 36 months following implantation. All children participated in individually tailored intensive audiological rehabilitation programs after receiving their implants. In this respect, it was attempted to evaluate speech perception scores in children implanted before and after the age of 3 in a homogenous group.

RESULTS

All children demonstrated encouraging improvements over time in their speech recognition abilities. Furthermore, it was observed that the children who were implanted under the age of 3 achieved higher levels of speech perception performance.

CONCLUSION

In order to shorten the process of central maturation of the auditory system, it is desirable to implant the children as young as possible. Early intervention seems to be the ideal strategy in enabling prelingually deaf children to derive maximum benefit from cochlear implantation.

Successful cochlear implantation in prelingual profound deafness resulting from the common 233delC mutation of the GJB2 gene in the Japanese

OBJECTIVES

Recently, we identified three novel mutations of the GJB2 gene in Japanese families with autosomal-recessive non-syndromic deafness.1 Seven of 11 mutated chromosomes (63.6%) contained a 233delC allele, suggesting that the 233delC mutation is the most common mutation of the GJB2 gene in the Japanese population. After it was recognized that cochlear implantation (CI) is of benefit to children with prelingual deafness, we have had a number of prelingual pediatric CI patients. Because children carrying the homozygous 233delC mutation show bilateral prelingual profound deafness, they could be enrolled in the CI program at Osaka University Graduate School of Medicine. The purposes of this study were 1) to analyze the occurrence of the GJB2 mutations in our 15 prelingual pediatric CI patients in whom the cause of non-syndromic deafness was unknown, and 2) to evaluate the auditory function and postoperative speech perception with CI of those GJB2-related deaf subjects.

STUDY DESIGN

Retrospective analysis.

METHODS

Mutation analysis of the GJB2 gene by direct sequencing was performed with genomic DNA from 15 children born profoundly deaf as a result of unknown causes and implanted with CI. Intraoperative electrically evoked auditory brainstem response (EABR) and intra-/postoperative EAP were measured. The speech perception was evaluated with Infants and Toddlers Meaningful Auditory Integration Scale (IT-MAIS).

RESULTS AND CONCLUSIONS

We identified 4 CI patients (26.7%) out of 15 children carrying the homozygous 233delC mutation. Intra- and postoperative evaluation of the auditory system revealed almost intact cochlear and retrocochlear auditory function in these 4 patients. Postoperative auditory testing indicates that their speech perception had become significantly higher in comparison with that of other prelingual CI patients. These results suggest that prelingual deaf children carrying the homozygous 233delC mutation of the GJB2 gene can benefit from CI.

Use of vocalic information in the identification of /s/ and /sh/ by children with cochlear implants

OBJECTIVE

When a syllable such as "sea" or "she" is spoken, listeners with normal hearing extract evidence of the fricative consonant from both the fricative noise and the following vocalic segment. If the fricative noise is made ambiguous, listeners may still perceive "s" or "sh" categorically, depending on information in the vocalic segment. Do children whose auditory experience comes from electrical stimulation also display this effect, in which a subsequent segment of speech disambiguates an earlier segment?

DESIGN

Unambiguous vowels were appended to ambiguous fricative noises to form tokens of the words "she," "sea," "shoe," and "Sue." A four-choice identification test was undertaken by children with normal hearing (N = 29), prelingually deaf children with the Nucleus Spectra-22 implant system using the SPEAK coding strategy (N = 13), postlingually deafened adults with the same implant system (N = 26), and adults with normal hearing (N = 10). The last group undertook the test before and after the stimuli were processed to simulate the transformations introduced by the SPEAK coding strategy.

RESULTS

All four groups made use of vocalic information. Simulated processing reduced the use made by normal-hearing adults. Implanted subjects made less use than the other groups, with no significant difference between implanted children and implanted adults. The highest levels of use by implanted subjects were within one standard deviation of the mean level displayed when normal-hearing adults listened to processed stimuli. Analyses showed that the SPEAK strategy distorted formant contours in the vocalic segments of the stimuli in ways that are compatible with the errors of identification made by implanted subjects.

CONCLUSIONS

Some children with implants can extract information from a following vowel to disambiguate a preceding fricative noise. The upper limit on this ability may be set by distortions introduced by the implant processor, rather than by the auditory experience of the child.

Communication development in young deaf children: review of the video analysis method

It is widely recognised that preverbal communication skills underpin development of spoken language. This historical review outlines the establishment of a quantitative methodology for assessing preverbal communication skills in children with hearing aids and cochlear implants. The method is shown to be reliable and free from observer bias. The review also summarises findings from a series of cross-sectional and longitudinal observational studies utilising the methodology. Profoundly deaf young children, either with cochlear implants or successful users of hearing aids, show similar patterns of preverbal communication development that contrast with those of unsuccessful hearing-aid users. Preverbal measures obtained 12 months after implantation are predictive of late performance on speech perception tasks. Moreover, there is a significant association between the preverbal measure of 'autonomy' obtained before implantation and later speech perception performance. This latter finding has important theoretical implications for understanding of language development and suggests that intervention that promotes autonomy in adult-child interaction may lead to improved outcomes. Such intervention could be commenced as soon as deafness is discovered.

Cochlear implantation in children with large vestibular aqueduct syndrome and a review of the syndrome

OBJECTIVE

Children with Large Vestibular Aqueduct Syndrome (LVAS) frequently develop speech and language skills prior to deterioration of their hearing. Operations designed to halt the progression of hearing loss have largely failed so the question of Cochlear Implantation in these children has arisen. It had been suggested that there would be technical difficulties in implanting these patients and, therefore, there had been an initial reluctance to proceed to implantation. The aim of the present paper is to assess surgical and functional outcomes in implanted children with LVAS and review the related literature.

MATERIAL AND METHODS

From the 170 children assessed by MRI in the Nottingham Paediatric Cochlear Implant Programme, seven (4%) were identified as having LVAS. Four of these children were implanted and had at least 12 months follow up. Two of the children are on the waiting list for implantation and one child was not implanted because of absence of the cochlear nerve. Operative findings, complications and outcome measures were recorded. The auditory skills of the children were assessed before implantation and 1 year following implantation. A literature search was done to identify other series with experience in implanting children with LVAS.

RESULTS

Full insertion of the electrode array was achieved in all our cases. After cochleostomy two patients experienced a mild CSF leak that was easily controlled by the muscle graft. On the first day post-operation two patients were nauseous and one had an episode of vomiting, however, all were discharged within 24 h of surgery. Initial outcome measures at 12 months post-implantation were encouraging showing significant progress in children's auditory skills.

CONCLUSIONS

The results of the present study and the review of the literature suggest that LVAS is not a contraindication to implantation as initial concerns about severe perilymph leaks and surgical complications have proved to be unfounded. The post-operative progress of these children in listening skills also suggest that these children are suitable for cochlear implantation

Health of teenagers in residential care: comparison of data held by care staff with data in community child health records

AIM

To identify whether there are gaps in information available to care staff about the health related needs of one group of teenagers in residential care which could be addressed by reviewing the community child health records.

METHODS

Data were collected on the residents of a children's home during a three month period, comparing information from children's home records with information from community child health records.

RESULTS

Data were collected from children's home records for 36 residents and child health records obtained for 29. Child health records provided the only information on 53% of child protection registrations and 17.5% of statements of special educational needs. Most information on birth history, developmental and early medical history, immunisations, growth, hearing, and colour vision came from the child health records. Immunisation uptake was below the national average, and particularly poor for BCG and school leaver tetanus, low dose diphtheria, and polio boosters. Emotional and behavioural problems were present in 100% of the residents and this information was known to the home. Poor use of "Looking After Children" records was identified, and there was a paucity of information in the home records and child health records about results of annual looked after medical examinations.

CONCLUSION

Important information about the health needs of looked after teenagers was not known to the children's home staff. Community paediatricians should be proactive in identifying and addressing these needs.