Editorial: Cochlear Implants: An Update

A cochlear implant (CI) is a hearing device introduced in the 1980s for profoundly deaf subjects who gained little or no benefit from powerful hearing aids. This device comprises an electrode array inserted in the cochlea, connected to an internal receiver, and an externally worn speech processor. The CI transforms acoustic signals into electrical currents which directly stimulate the auditory nerve. Since the early 1990s, cochlear implantation in children has been developing rapidly. Although it is still difficult to predict how a child will perform with a cochlear implant, the success of cochlear implantation can no longer be denied. In this paper, some recent papers and reports, and the results of the various Nijmegen cochlear implant studies, are reviewed. Issues about selection, examinations, surgery and the outcome are discussed. Overall, our results were comparable with those of other authors. It can be concluded that cochlear implantation is an effective treatment for postlingually deaf as well as prelingually (congenital or acquired) deaf children with profound bilateral sensorineural deafness.

BackgroundDeafness has an adverse impact on children's ability to acquire spoken languages. Signed languages offer a more accessible input for deaf children, but because the vast majority are born to hearing parents who do not sign, their early exposure to sign language is limited. Deaf children as a whole are therefore at high risk of language delays.AimsWe compared deaf and hearing children's performance on a semantic fluency task. Optimal performance on this task requires a systematic search of the mental lexicon, the retrieval of words within a subcategory and, when that subcategory is exhausted, switching to a new subcategory. We compared retrieval patterns between groups, and also compared the responses of deaf children who used British Sign Language (BSL) with those who used spoken English. We investigated how semantic fluency performance related to children's expressive vocabulary and executive function skills, and also retested semantic fluency in the majority of the children nearly 2 years later, in order to investigate how much progress they had made in that time.Methods & ProceduresParticipants were deaf children aged 6–11 years (N = 106, comprising 69 users of spoken English, 29 users of BSL and eight users of Sign Supported English—SSE) compared with hearing children (N = 120) of the same age who used spoken English. Semantic fluency was tested for the category ‘animals’. We coded for errors, clusters (e.g., ‘pets’, ‘farm animals’) and switches. Participants also completed the Expressive One‐Word Picture Vocabulary Test and a battery of six non‐verbal executive function tasks. In addition, we collected follow‐up semantic fluency data for 70 deaf and 74 hearing children, nearly 2 years after they were first tested.Outcomes & ResultsDeaf children, whether using spoken or signed language, produced fewer items in the semantic fluency task than hearing children, but they showed similar patterns of responses for items most commonly produced, clustering of items into subcategories and switching between subcategories. Both vocabulary and executive function scores predicted the number of correct items produced. Follow‐up data from deaf participants showed continuing delays relative to hearing children 2 years later.Conclusions & ImplicationsWe conclude that semantic fluency can be used experimentally to investigate lexical organization in deaf children, and that it potentially has clinical utility across the heterogeneous deaf population. We present normative data to aid clinicians who wish to use this task with deaf children.

This study investigated peripheral vision (at least 30° eccentric to fixation) development in profoundly deaf children without cochlear implantation, and compared this to age-matched hearing controls as well as to deaf and hearing adult data. Deaf and hearing children between the ages of 5 and 15 years were assessed using a new, specifically paediatric designed method of static perimetry. The deaf group (N = 25) were 14 females and 11 males, mean age 9.92 years (range 5-15 years). The hearing group (N = 64) were 34 females, 30 males, mean age 9.13 years (range 5-15 years). All participants had good visual acuity in both eyes (< 0.200 LogMAR). Accuracy of detection and reaction time to briefly presented LED stimuli of three light intensities, at eccentricities between 30° and 85° were measured while fixation was maintained to a central target. The study found reduced peripheral vision in deaf children between 5 and 10 years of age. Deaf children (aged 5-10 years) showed slower reaction times to all stimuli and reduced ability to detect and accurately report dim stimuli in the far periphery. Deaf children performed equally to hearing children aged 11-12 years. Deaf adolescents aged 13-15 years demonstrated faster reaction times to all peripheral stimuli in comparison to hearing controls. Adolescent results were consistent with deaf and hearing adult performances wherein deaf adults also showed significantly faster reaction times than hearing controls. Peripheral vision performance on this task was found to reach adult-like levels of maturity in deaf and hearing children, both in reaction time and accuracy of detection at the age of 11-12 years.

Deafness is a sensory impairment which strongly affects the normal acquisition and development of linguistic abilities. Deaf people are severely hindered in the development of oral speech because they do not have direct access to the linguistic input and many of them do not acquire much more than the rudiments of oral communication. While hearing children acquire easily and naturally a spoken language, deaf children might acquire in the same way a sign language, exploiting the visual modality. This study investigated the general linguistic competence in Italian of four different groups of deaf individuals (orally-trained children with cochlear implants, native signers, non-native signers and deaf foreigners adolescents and adults), by using a standardized picture matching task, in order to determine the level of their linguistic competence. Results revealed that most deaf individuals showed a performance comparable to that of very young hearing children. Cochlear implanted children performed significantly better than all the other groups, and the less accurate performance was that of foreigner deaf students, who often have not any kind of underlying language. Despite the better performance of cochlear implanted children, who generally do not use the sign language, the best solution to approach the oral language would appear to be the combination of oral training and sign language, in order to be able to communicate with both the deaf and the hearing communities. The school system in this sense should find some strategies in order to help deaf foreigners to get access to the grammar of the oral language.

A005 Biofilms and cochlear implants – the dilemma

B029 Cochlear implantation in incomplete partition I

B006 Cochleostomy versus round window approach in children, comparation

B049 Predicion of speech percetion with cochlear implants

The reading comprehension and visual word recognition in 50 deaf children and adolescents with at least 3 years of cochlear implant (CI) use were evaluated. Their skills were contrasted with reference data of 500 deaf children without CIs. The reading comprehension level in children with CIs was expected to surpass that in deaf children without implants, partly via improved visual word recognition. Reading comprehension scores of children with implants were significantly better than those of deaf children without implants, although the performance in implant users was substantially lagging behind that in hearing children. Visual word recognition was better in children with CIs than in children without implants, in secondary education only. No difference in visual word recognition was found between the children with CIs and the hearing children, whereas the deaf children without implants showed a slightly poorer performance. The difference in reading comprehension performance of the deaf children with and without CIs remained present when visual word recognition was controlled for. This indicates that other reading-related skills were also contributing to the improved reading comprehension skills of deaf children with CIs.

Perspectives on academic and social aspects of children’s school experiences were obtained from deaf and hearing children and their (deaf or hearing) parents. Possible differences between (1) the views of children and their parents and (2) those of hearing children and their parents compared to deaf children and their parents were of particular interest. Overall, parents gave their children higher school friendship ratings than the children gave themselves, and hearing children and their parents were more positive about children’s friendships than were deaf children and their parents. Both children and parents also saw deaf children as less successful in reading than hearing children. However, deaf children having deaf parents, attending a school for the deaf and using sign language at home all were associated with more positive perceptions of social success. Use of cochlear implants was not associated with perceptions of greater academic or social success. These and related findings are discussed in the context of parent and child perspectives on social and academic functioning and particular challenges confronted by deaf children in regular school settings.

Semantic categorization: A comparison between deaf and hearing children

To address the negative effects of deafness on spoken language acquisition, many clinicians suggest using cochlear implant (CI) and oral education and advise against sign language, even when combined with spoken language (i.e., bilingualism), believing that it may slow down spoken language development. In a deaf child with CI who was exposed at an early age to Italian Sign Language and spoken Italian, we evaluated language development and the relationship between the two languages. The number of words/signs produced by the child consistently increased with age, and the vocabulary growth rate in spoken Italian was equivalent to that of hearing peers. Before CI, the child relied almost exclusively on sign language; after CI, he gradually shifted to spoken Italian yet still used sign language when unable to retrieve words in spoken Italian. We conclude that bimodal bilingualism may scaffold the development of spoken language also in deaf children with CI.

A cochlear implant is a sensory aid that uses a surgically implanted electrode array threaded within the scala tympani of the cochlea to present an electrical representation of sound directly to the auditory nerve of individuals who have a severe to profound bilateral sensorineural hearing loss. Cochlear implants work and they work reasonably well in many profoundly deaf adults and children. For these patients, a cochlear implant (CI) is a form of intervention, an alternative way of providing access to sound using electrical stimulation of the auditory system (see Niparko, Chapter 3). For postlingually deafened adults, a cochlear implant serves primarily as a sensory aid to restore lost hearing and regain contact with the world of sound as they knew it before the onset of their deafness. For the prelingually deaf child, in contrast, the electrical stimulation provided by a cochlear implant represents the introduction of a new sensory modality and an additional way to acquire knowledge about sound, sound sources, and the correlations between objects and events in their environment. Perhaps the most important benefit of a cochlear implant, however, is that it provides the prelingually deaf child with access to information about speech and spoken language.

In this article, we look at sign duration and signing rate in corpora of three sign languages – British Sign Language (BSL), Dutch Sign Language (NGT), and Swedish Sign Language (STS). We investigate whether token frequency and sociolinguistic variables (e.g., age, gender, region) influence the production rate of signing. Following Zipf’s law of abbreviation, we see that a sign’s duration is negatively correlated with its frequency. Both sign duration and signing rate are found to correlate with signer age, in that older signers have longer durations and lower rates than younger signers. Signers' gender, family (deaf or hearing), and age of exposure have no effect on duration or signing rate. For NGT and STS, there is no effect of region on either duration or rate. However, in the BSL data, duration and signing rate vary with region. The overall findings align with previous work on spoken languages, particularly that frequency and aging are correlated with word length and production rate, thus demonstrating such patterns across modalities of language.

An increasing number of deaf children received cochlear implants (CI) in the first years of life, but no study has focused on linguistic and pragmatic skills in children with CI younger than 3 years of age. To estimate the percentage of children who had received a CI before 2 years of age whose linguistic skills were within the normal range; to compare linguistic skills of children implanted by 12 months of age with children implanted between 13 and 26 months of age; and to describe the relationship among lexical, grammar and pragmatic skills. The participants consisted of children who were included on the patient lists of the Service of Audio-Vestibology of the Circolo Hospital in Varese, Italy, and met the following criteria: chronological age between 18 and 36 months; CI activated between 8 and 30 months of age; absence of other reported deficits; hearing parents; and not less than 6 months of CI experience. Language development was evaluated through MacArthur-Bates CDI; pragmatic skills (assertiveness and responsiveness) were evaluated through the Social Conversational Skills Rating Scale. The scores obtained were transformed into z-scores and compared with normative data. The relationship among lexical, grammar and pragmatic skills were tested using Spearman Rho correlations. Children with CI were divided into groups based on the age at CI activation and the differences between the two groups were tested using the Student's t-test. Data from 23 deaf children were collected. Fewer than half of the children were within the normal range for lexical production and use of sentences; more than one-third of them fell below the normal range for both lexical and grammar skills. No significant difference was found in vocabulary size or early grammar skills when comparing children who received the CI by 12 months of age with those implanted during the second year of life. Despite the strong relationship among lexical, grammar and pragmatic skills, the delays found for grammar and pragmatic skills were greater than expected based on the vocabulary size. Age at diagnosis of hearing loss was the only predictor of vocabulary size. CI may provide deaf children with a good opportunity to develop language skills, but severe difficulties in early social experiences and interaction mediated by language still remain. Delays in these aspects suggest that interventions improving pragmatic skills are recommended even on very young children with CI.