Years Of Cochlear Implant Use Research Articles

Children then, adults now: long-term outcomes-performance at 15, 20, and 25 years of cochlear implant use.

Severe to profound sensorineural hearing loss interferes with a child's development at the cognitive, linguistic, academic, and social levels. Since the beginning of the pediatric auditory rehabilitation program through cochlear implantation in the Ear, Nose, and Throat (ENT) Service of the Coimbra Hospital and University Center (CHUC), Portugal, its mentors defended the early diagnosis of hearing loss followed by timely intervention, and this was considered the starting point to optimize (re)habilitation through this method. Three decades or so later, recently we conducted this study to evaluate the performance of patients implanted in the initial phase of the cochlear implantation program. The study aimed to evaluate the performance of individuals with severe to profound congenital hearing loss who underwent pediatric cochlear implantation and have used the cochlear implant for at least 25 years, to analyze the beneficial effect of early intervention in improving performance results. The study sample is composed of 31 individuals with severe to profound congenital hearing loss and no other comorbidities, divided into two groups (Group 1: age at implantation was under 3 years; Group 2: age at implantation was over 3 years). All 31 subjects were evaluated at 15, 20, and 25 years of cochlear implant (CI) use with a comprehensive set of tests. In addition, data were collected regarding the academic level of each participant. The results of both groups were compared to find out if there is an effect of age at implantation on auditory performance, and if there is an improvement in the performance with CI over time (15, 20, and 25 years of use). The results show that there is a positive effect, with statistical significance, of early implantation on auditory performance, and telephone use. In both groups, there is an increase in performance over time, but it tends to stabilize after 20 years of CI use. The results obtained in this work support the importance of early intervention in patients with severe to profound hearing loss who are cochlear implant users and show that CI is an effective and reliable method in the treatment of these patients, contributing to their improved socio-educational integration, and that the benefits last over time.

Communicative and Hearing Performance in Individuals with Cochlear Implants and Delayed Neuropsychomotor Development: A Longitudinal Analysis.

Introduction Between 15% to 30% of individuals with bilateral prelingual sensorineural hearing loss present with associated disabilities. Cochlear implant (CI) is an alternative treatment that provides consistent access to environmental and speech sounds, which results in significant benefits regarding quality of life and auditory and language development. Objectives To study the auditory and communicative performance of individuals with CI and delayed neuropsychomotor development after a minimum of five years using the device. Methods A total of eight patients were included in the study. We collected the multidisciplinary clinical records of participants, as well as the answers for the questionnaires applied remotely, which included the Children with Cochlear Implants: Parental Perspectives (CCIPP), International Classification of Functioning, Disability and Health: Children and Youth Version (ICF-CY), and the Gross Motor Function Classification System (GMFCS). Results We found that throughout the years of CI use, the auditory threshold means improved significantly in all tested frequencies, as did the speech detection threshold and the language and hearing results. Regarding parental perception, parents evaluated aspects related to their children's social relations to be positive, and had worse perceptions regarding aspects related to their education. Conclusion We observed a progression in the participants' auditory and language skills throughout the years of CI use; even in the presence of other associated disabilities. Future multicentric studies with larger samples are needed to further the advancement of rehabilitation in patients with other associated disabilities.

Early grammar-building in French-speaking deaf children with cochlear implants: A follow-up corpus study.

One of the most consistent findings reported in the paediatric cochlear implant (CI) literature is the heterogeneity of language performance observed more in grammatical morphology than in lexicon or pragmatics. As most of the corpus studies addressing these issues have been conducted in English, it is unclear whether their results can be generalized to other languages. In particular, little is known about languages known for their grammatical complexity, such as French. The aim of this corpus study was to compare the productive use of function words (FWs) and some agreement features (AGRs) in children with CIs and children with typical development (TD) matched for mean length of utterance in words (MLUwords ), a general index of grammatical complexity, and auditory experience, as measured by hearing age (HA) and chronological age (CA), respectively. Natural speech samples from 116 monolingual French-speaking children, including 40 children with CIs followed longitudinally and 76 TD children, were collected. FWs and AGRs were analysed using a Part of Speech Tagger (POS-T) from the Child Language Data Exchange System (CHILDES). The two groups differed by 3 years for HA and CA. No effect of family socio-economic status (SES) was found in the CI group. Stepwise regression analyses showed that the two groups did not share the same predictors of MLUwords : plurals and determiners predicted MLUwords in children with CIs, at 2 and 3 years of HA, whereas feminine markers and subject-pronouns were found to best predict MLUwords in TD children at 2 and 3 years of CA. Structural equation models (SEMs), a combination of confirmatory factor analysis (CFA) and path analysis, yielded a different hierarchical structure of grammatical relations (GRs). Selective difficulties affecting verbal clitics and other pronominal forms were found specifically in the CI group (object-pronouns, reflexive, relative and past participles). Dependency grammar analysis confirmed these contrasting developmental profiles in multiword utterances, such as preposition/nouns, subject/verbs, and verb/determiner/nouns. Atypical grammatical patterns in children with CIs reflect a specific architecture of syntactic dependencies of FWs underpinning morphological complexity and syntactic connectivity. Clinical implications are discussed for assessment and intervention planning. What is already known on this subject The productive use of FWs has been identified as a particular area of weakness in children with CIs compared with TD children. In addition, heterogenous grammatical performance has often been found after 1-3 years of CI use, regardless of demographic factors such as age at implantation, duration of deafness or SES. What this paper adds to existing knowledge Assessing the early building of FWs and AGRs in children with CIs helps to understand the syntactic complexity and hierarchical structure of their language. Since most corpus studies on grammatical morphology have been conducted in English, it is not clear whether their difficulties can be generalized to other languages. The French language has a system of FWs and inflections that determine the morphophonological properties of nominal and verbal forms. Early grammar learning in children with CIs born with profound deafness were compared with the two groups of TD children matched both for duration of auditory experience (i.e., HA of CI children, CA of TD children) and for MLUwords . We found a similar profile between groups at 2 years but not at 3 years for HA and CA. The two groups do not share the same predictors of MLUwords : namely, plurals and determiners for CI children versus feminine markers and subject pronouns for TD children. They show a different syntactic organization of GRs. Children with CIs struggle with selective difficulties affecting verbal clitics and pronominal forms (object-pronouns, reflexive, relative and past participles). Consistent with theories of morphophonological richness and syntactic connectivity, our results support the distributional learning hypothesis of language acquisition that infants and toddlers are sensitive to FWs and AGRs at an early age. Specific components of syntactic organization are disrupted in children with CIs. What are the potential or actual clinical implications of this work? This work has potential clinical implications because it unravels the limitations of morphophonological processing in children with CIs. Its results highlight a specific difficulty in learning FWs and AGRs in a verbal inflectional morphology context.

Normative Cochlear Implant Quality of Life (CIQOL)-35 Profile and CIQOL-10 Global Scores for Experienced Cochlear Implant Users from a Multi-Institutional Study.

Although adult cochlear implant (CI) outcomes have primarily focused on speech recognition scores, the rigorous development of a CI-specific patient-reported outcome measure provides an opportunity for a more comprehensive and ecologically valid approach to measure the real-world functional abilities of adult CI users. Here, we report for the first time normative Cochlear Implant Quality of Life (CIQOL)-35 Profile and global scores and variance for a large, multi-institutional sample of adult CI users. Cross-sectional study design. CI centers in the United States. Seven hundred five adults with bilateral moderate to profound hearing loss with at least 1 year of CI use. Cochlear implantation. CIQOL-35 Profile and CIQOL-10 Global scores. During the development of the CIQOL instruments, 1,000 CI users from all regions of the United States were invited to participate in studies. Of these, 705 (70.5%) completed all portions of the study, and their data are reported here. Mean CIQOL domain scores were highest (indicating better function) for the emotional and social domains and lowest for listening effort. The entertainment and social domains demonstrated the widest distribution of scores and largest standard deviations, indicating greatest variability in function. Overall, there were minimal ceiling and floor effects for all domains. Normative scores from a large sample of experienced adult CI users are consistent with clinical observations, showing large differences in functional abilities and large variability. Normative CIQOL data for adult CI users have the potential to enhance preoperative discussions with CI candidates, improve post-CI activation monitoring, and establish standards for CI centers.

Upward Shifts in the Internal Representation of Frequency Can Persist Over a 3-Year Period for Cochlear Implant Patients Fit With a Relatively Short Electrode Array

Patients fit with cochlear implants (CIs) commonly indicate at the time of device fitting and for some time after, that the speech signal sounds abnormal. A high pitch or timbre is one component of the abnormal percept. In this project, our aim was to determine whether a number of years of CI use reduced perceived upshifts in frequency spectrum and/or voice fundamental frequency. The participants were five individuals who were deaf in one ear and who had normal hearing in the other ear. The deafened ears had been implanted with a 18.5 mm electrode array which resulted in signal input frequencies being directed to locations in the spiral ganglion (SG) that were between one and two octaves higher than the input frequencies. The patients judged the similarity of a clean signal (a male-voice sentence) presented to their implanted ear and candidate, implant-like, signals presented to their normal-hearing (NH) ear. Matches to implant sound quality were obtained, on average, at 8 months after device activation (see section “Time 1”) and at 35 months after activation (see section “Time 2”). At Time 1, the matches to CI sound quality were characterized, most generally, by upshifts in the frequency spectrum and in voice pitch. At Time 2, for four of the five patients, frequency spectrum values remained elevated. For all five patients F0 values remained elevated. Overall, the data offer little support for the proposition that, for patients fit with shorter electrode arrays, cortical plasticity nudges the cortical representation of the CI voice toward more normal, or less upshifted, frequency values between 8 and 35 months after device activation. Cortical plasticity may be limited when there are large differences between frequencies in the input signal and the locations in the SG stimulated by those frequencies.

Long-Term Improvement in Localization for Cochlear Implant Users with Single-Sided Deafness.

To assess whether early, significant improvements in sound source localization observed in cochlear implant (CI) recipients with normal hearing (NH) in the contralateral ear are maintained after 5 years of CI use. Prospective, repeated measures study. Participants were recruited from a sample of CI + NH listeners (n=20) who received their device as part of a prospective clinical trial investigating outcomes of CI use for adult cases of single-sided deafness. Sound source localization was assessed annually after the clinical trial endpoint (1-year post-activation). Listeners were asked to indicate the perceived sound source for a broadband noise burst presented randomly at varied intensity levels from one of 11 speakers along a 180° arc. Performance was quantified as root-mean-squared (RMS) error. Linear mixed models showed superior post-activation performance was maintained with long-term CI use as compared to preoperative abilities (P < .001). Unexpectedly, a significant improvement (P=.009) in sound source localization was observed over the long-term post-activation period (1-5 years). To better understand these long-term findings, the response patterns for the 11 participants who were evaluated at the 1- and 5-year visits were reviewed. This subgroup demonstrated a significant improvement in RMS error (P=.020) and variable error (P=.031), indicating more consistent responses at the 5-year visit. Adult CI + NH listeners experience significant improvements in sound source localization within the initial weeks of listening experience, with additional improvements observed after long-term device use. The present sample demonstrated significant improvements between the 1-year and 5-year visits, with greater accuracy and consistency noted in their response patterns. 3 Laryngoscope, 132:2453-2458, 2022.

Eyes Open, Ears On: Supporting Hearing Technology Use in Children with Hearing Loss

Eyes Open, Ears On: Supporting Hearing Technology Use in Children with Hearing Loss

Long-Term Follow-Up of Early Cochlear Implant Device Activation

Background: The cochlear implant (CI) is a standard procedure for the treatment of patients with severe to profound hearing loss. In the past, a standard healing period of 3–6 weeks occurred after CI surgery before the sound processor was initially activated. Advancements of surgical techniques and instruments allow an earlier initial activation of the processor within 14 days after surgery. Objective: Evaluation of the early CI device activation after CI surgery within 14 days, comparison to the first activation after 4–6 weeks, and assessment of the feasibility and safety of the early fitting over a 12 month observation period were the objectives of this study. Method: In a prospective study, 127 patients scheduled for CI surgery were divided into early fitting group (EF, n = 67) and control group (CG, n = 60). Individual questionnaires were used to evaluate medical and technical outcomes of the EF. Medical side effects, speech recognition, and follow-up effort were compared with the CG within the first year after CI surgery. Results: The early fitting was feasible in 97% of the EF patients. In the EF, the processor was activated 25 days earlier than in the CG. No major complications were observed in either group. At the follow-up appointments, side effects such as pain and balance problems occurred with comparable frequency in both groups. At initial fitting, the EF showed a significantly higher incidence of medical minor complications (p < 0.05). When developing speech recognition within the first year of CI use, no difference was observed. Furthermore, the follow-up effort within the first year after CI surgery was comparable in both groups. Conclusions: Early fitting of the sound processor is a feasible and safe procedure with comparable follow-up effort. Although more early minor complications were observed in the EF, there were no long-term wound healing problems caused by the early fitting. Regular inspection of the magnet strength is recommended as part of the CI follow-up since postoperative wound swelling must be expected. The early fitting procedure enabled a clear reduction in the waiting time between CI surgery and initial sound processor activation.

Cognitive Improvement After Cochlear Implantation in Older Adults With Severe or Profound Hearing Impairment: A Prospective, Longitudinal, Controlled, Multicenter Study.

Objective:To compare the cognitive evolution of older adults with severe or profound hearing impairment after cochlear implantation with that of a matched group of older adults with severe hearing impairment who do not receive a cochlear implant (CI).Design:In this prospective, longitudinal, controlled, and multicenter study, 24 older CI users were included in the intervention group and 24 adults without a CI in the control group. The control group matched the intervention group in terms of gender, age, formal education, cognitive functioning, and residual hearing. Assessments were made at baseline and 14 months later. Primary outcome measurements included the change in the total score on the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing impaired individuals score and on its subdomain score to assess cognitive evolution in both groups. Secondary outcome measurements included self-reported changes in sound quality (Hearing Implant Sound Quality Index), self-perceived hearing disability (Speech, Spatial, and Qualities of Hearing Scale), states of anxiety and depression (Hospital Anxiety and Depression Scale), and level of negative affectivity and social inhibition (Type D questionnaire).Results:Improvements of the overall cognitive functioning (p = 0.05) and the subdomain “Attention” (p = 0.02) were observed after cochlear implantation in the intervention group; their scores were compared to the corresponding scores in the control group. Significant positive effects of cochlear implantation on sound quality and self-perceived hearing outcomes were found in the intervention group. Notably, 20% fewer traits of Type D personalities were measured in the intervention group after cochlear implantation. In the control group, traits of Type D personalities increased by 13%.Conclusion:Intervention with a CI improved cognitive functioning (domain Attention in particular) in older adults with severe hearing impairment compared to that of the matched controls with hearing impairment without a CI. However, older CI users did not, in terms of cognition, bridge the performance gap with adults with normal hearing after 1 year of CI use. The fact that experienced, older CI users still present subnormal cognitive functioning may highlight the need for additional cognitive rehabilitation in the long term after implantation.

The French Cochlear Implant Registry (EPIIC): Cochlear implant candidacy assessment of off-label indications

ObjectiveEvaluate in France the outcomes of cochlear implantation outside the selection criteria, off-label. Material and methodsThis is a prospective cohort study including adults and children having received a cochlear implant (CI) in an off-label indication, that is outside the criteria established by the “Haute Autorité de santé (HAS)” in 2012. The data was collected from the “EPIIC” registry on recipients who received CIs in France between 2011 and 2014. Speech audiometry was performed at 60dB preimplantation and after one year of CI use, as well as an evaluation of the scores of the quality of life with the APHAB questionnaire, the scores for CAP and the professional/academic status in pre- and post-implantation conditions. Major and minor complications at surgery have been recorded. ResultsIn total, 590 patients (447 adults and 143 children) with an off-label indication for CIs were included in this study from the EPIIC registry (11.7% of the whole cohort of EPIIC). For adults, the median percentage of comprehension using monosyllabic word lists was 41% in preimplantation condition versus 53% after one year of CI use (P<0.001) and 60% versus 71% in dissyllabic word lists (P<0.001). The CAP scores were 5 versus 6 in pre- and post-implantation conditions respectively (P<0.001) and the APHAB scores were statistically lower after implantation (P<0.001). In the children cohort, the median percentage of comprehension using monosyllabic word lists was 51% in preimplantation condition and 65% after CI (P<0.001), and 48% versus 82% (P<0.001) for dissyllabic word lists. The CAP scores were 5 versus 7 respectively in pre- and post-CI conditions (P<0.001). Thirty-two minor complications (5.4%) and 17 major complications (2.8%) were reported in our panel of off-label indication patients. ConclusionThese results suggest that a revision of the cochlear implantation candidacy criteria is necessary to allow more patients with severe or asymmetric hearing loss to benefit from a CI when there is an impact on quality of life despite the use of an optimal hearing aid.

Long-Term Influence of Electrode Array Length on Speech Recognition in Cochlear Implant Users.

Results from a prospective trial demonstrated better speech recognition for cochlear implant (CI) recipients implanted with a long lateral wall electrode array compared to subjects with a short array after 1 year of listening experience. As short array recipients may require an extended adaptation period, this study investigated whether differences in speech recognition continued through 4 years of CI use. Long-term follow-up of a prospective randomized trial. Subjects were randomized to receive a MED-EL medium (24 mm) or standard (31.5 mm) array. Linear mixed models compared speech recognition between cohorts with word recognition in quiet and sentence recognition in noise at 1, 3, 6, 12, 24, and 48 months postactivation. Postoperative imaging and electric frequency filters were reviewed to assess the influence of frequency-to-place mismatch and angular separation between neighboring contacts, a metric associated with peripheral spectral selectivity. Long (31.5 mm) array recipients demonstrated superior speech recognition out to 4 years postactivation. There was a significant effect of angular separation between contacts, with more closely spaced contacts associated with poorer speech recognition. There was no significant effect of mismatch, yet this may have been obscured by changes in frequency filters over time. Conventional MED-EL CI recipients implanted with 31.5-mm arrays experience better speech recognition than 24-mm array recipients, initially and with long-term listening experience. The benefit conferred by longer arrays in the present cohort can be partially attributed to more widely spaced electrode contacts, presumably a result of reduced channel interaction. 2 Laryngoscope, 131:892-897, 2021.

Evaluating the Long-Term Hearing Outcomes of Cochlear Implant Users With Single-Sided Deafness.

To investigate the long-term outcomes of cochlear implantation in individuals with single-sided deafness (SSD) in terms of speech perception, subjective hearing performance, and sound localization. Thirty-four subjects with SSD were recruited across two large cochlear implant (CI) centers (Antwerp, Belgium and Perth, Australia). The long-term hearing outcomes (between 4 and 10 years of CI use) were evaluated using speech in noise tests, a subjective hearing performance questionnaire (Speech, Spatial and Qualities Questionnaire [SSQ12]), and sound localization tests. Statistically significant improvements were observed in speech perception in noise and sound localization results postoperatively with the use of a CI in comparison to preoperative measurements. Subjective hearing abilities also significantly improved after long-term CI use. Access to binaural hearing is important for subjects with SSD. CI users with SSD experience long-term benefits in speech understanding, sound localization, and quality of life.

Establishing a mental lexicon with cochlear implants: an ERP study with young children

In the present study we explore the implications of acquiring language when relying mainly or exclusively on input from a cochlear implant (CI), a device providing auditory input to otherwise deaf individuals. We focus on the time course of semantic learning in children within the second year of implant use; a period that equals the auditory age of normal hearing children during which vocabulary emerges and extends dramatically. 32 young bilaterally implanted children saw pictures paired with either matching or non-matching auditory words. Their electroencephalographic responses were recorded after 12, 18 and 24 months of implant use, revealing a large dichotomy: Some children failed to show semantic processing throughout their second year of CI use, which fell in line with their poor language outcomes. The majority of children, though, demonstrated semantic processing in form of the so-called N400 effect already after 12 months of implant use, even when their language experience relied exclusively on the implant. This is slightly earlier than observed for normal hearing children of the same auditory age, suggesting that more mature cognitive faculties at the beginning of language acquisition lead to faster semantic learning.

Cochlear implant in postlingual children: functional results 10 years after the surgery

The benefits of cochlear implants (CI) for communication skills are obtained over the years. There are but a few studies regarding the long-term outcomes in postlingual deaf children who grew up using the electronic device. AimTo assess the functional results in a group of postlingual children, 10 years after using a CI. MethodsTen postlingual deaf children, implanted before 18 years of age, participated in this study. We assessed: sentence recognition and speech intelligibility. We documented: device use and function and the patient's academic/occupational status. Study design: series. ResultsThe mean scores were 73% for sentence recognition in silence and 40% in noise. The average write-down intelligibility score was 92% and the average rating-scale intelligibility score was 4.15. There were no cases of device failure. Regarding educational/vocational status, three subjects graduated from the University. Five quit education after completing high school. Eight subjects had a professional activity. ConclusionThis study showed that cochlear implantation is a safe and reliable procedure. The postlingual profoundly hearing-impaired children after 10 years of CI use developed satisfactory levels regarding speech perception and intelligibility, and completed at least high school and were inserted in the labor market. Clinical Trials Registry: NCT01400178.

Event-related potentials for better speech perception in noise by cochlear implant users

Speech perception in noise is still difficult for cochlear implant (CI) users even with many years of CI use. This study aimed to investigate neurophysiological and behavioral foundations for CI-dependent speech perception in noise. Seventeen post-lingual CI users and twelve age-matched normal hearing adults participated in two experiments. In Experiment 1, CI users' auditory-only word perception in noise (white noise, two-talker babble; at 10 dB SNR) degraded by about 15%, compared to that in quiet (48% accuracy). CI users' auditory-visual word perception was generally better than auditory-only perception. Auditory-visual word perception was degraded under information masking by the two-talker noise (69% accuracy), compared to that in quiet (77%). Such degradation was not observed for white noise (77%), suggesting that the overcoming of information masking is an important issue for CI users' speech perception improvement. In Experiment 2, event-related cortical potentials were recorded in an auditory oddball task in quiet and noise (white noise only). Similarly to the normal hearing participants, the CI users showed the mismatch negative response (MNR) to deviant speech in quiet, indicating automatic speech detection. In noise, the MNR disappeared in the CI users, and only the good CI performers (above 66% accuracy) showed P300 (P3) like the normal hearing participants. P3 amplitude in the CI users was positively correlated with speech perception scores. These results suggest that CI users’ difficulty in speech perception in noise is associated with the lack of automatic speech detection indicated by the MNR. Successful performance in noise may begin with attended auditory processing indicated by P3.

Subjective evaluation of cochlear implants through a questionnaire survey in 100 long term adult cochlear implant users

The satisfaction level is one of the important parameters to evaluate the effectiveness of cochlear implant (CI) in adult CI users. The purpose of this study is to investigate what factor improves the satisfaction level in adult CI users. Questionnaires were used to evaluate the items concerning the satisfaction level. One hundred patients who underwent cochlear implant placement at or over the age of 20 years were enrolled in this study. All patients had an experience of at least 5 years of CI use. To evaluate the effect of CI, questionnaire items were answered about the common communicative methods, listening under various situations, points of dissatisfaction, useful level, anxiety level without CI, satisfaction level, and the duration of CI usage. Sixty two percent of the patients were satisfied with the effect of CI and 80% felt that their CI was useful. Their listening results tended to be better in quieter environments or conversation in small groups. Furthermore, listening was related to the useful and satisfaction levels. Therefore, the better they could hear, the more they were satisfied with their CI, and appreciated its usefulness. The frequency of using CI as a communicative method (application level of CI) was statistically related to useful level, but no statistical relationship was seen between the application level of CI and anxiety level or satisfaction levels. These results suggest that other factors such as psychological status might affect the satisfaction level in addition to the CI application level. We concluded that it was necessary for us to understand the listening level before CI surgery in order to predict the postoperative course and to give an appropriate explanation to the patients.

Spoken English Language Development Among Native Signing Children With Cochlear Implants

Bilingualism is common throughout the world, and bilingual children regularly develop into fluently bilingual adults. In contrast, children with cochlear implants (CIs) are frequently encouraged to focus on a spoken language to the exclusion of sign language. Here, we investigate the spoken English language skills of 5 children with CIs who also have deaf signing parents, and so receive exposure to a full natural sign language (American Sign Language, ASL) from birth, in addition to spoken English after implantation. We compare their language skills with hearing ASL/English bilingual children of deaf parents. Our results show comparable English scores for the CI and hearing groups on a variety of standardized language measures, exceeding previously reported scores for children with CIs with the same age of implantation and years of CI use. We conclude that natural sign language input does no harm and may mitigate negative effects of early auditory deprivation for spoken language development.

The mismatch negativity (MMN) brain response to sound frequency changes in adult cochlear implant recipients: a follow-up study

Conclusion: Plasticity of auditory pitch discrimination driven by cochlear implant (CI) use uring a 2.5-year follow-up was indicated by an enhancement of the amplitude of mismatch negativity (MMN) event-related brain potential (ERP) to pure tone frequency changes. Objectives: To follow up changes in MMN elicited to frequency and duration changes in tones during 2.5 years of CI use and to compare MMN results with audiometric speech recognition scores (SRSs). Methods: Postlingually deafened adults with Cochlear Nucleus CI-22 and spectra processor with SPEAK strategy were recruited. MMN was measured at 1 and 2.5 years after CI activation. Repetitive 100 ms standard tones with a frequency of 500, 1000, 2000 or 4000 Hz in separate sequences were delivered to participants concentrating on a silent movie. Deviant tones occurring infrequently among standard tones were 20% lower in frequency or 50% shorter in duration than the standards. Speech recognition ability was followed with SRSs. Results: Both time from CI activation and the frequency range of tones had significant effects on the MMN amplitude. A significant enhancement was observed for the MMN elicited by 3200 Hz deviant tones among 4000 Hz standards. Also SRSs significantly increased with time and correlated with MMN amplitudes to the 3200 Hz deviants in both measurements.

A Longitudinal Study of Lexical and Grammar Development in Deaf Italian Children Provided With Early Cochlear Implantation

A growing number of studies on deaf children with cochlear implant (CI) document a significant improvement in receptive and expressive language skills after implantation, even if they show language delay when compared with normal-hearing peers. Data on language acquisition in CI Italian children are still scarce and limited to only certain aspects of language. The purpose of this study is to prospectively describe the trajectories of language development in early CI Italian children, with particular attention to the transition from first words to combinatorial speech and to acquisition of complex grammar in a language with rich morphology, such as Italian. Six children, with profound prelingual deafness, provided with CI, between 16 and 24 months of age were prospectively assessed and followed over a mean period of up to 34.8 months postimplant. During follow-up, each child received between four to five individual language evaluations through a combination of indirect procedures (parent reports of early lexical and grammar development) and direct ones (administration of standardized receptive and expressive language tests with Italian norms and collection of spontaneous language samples). In relation to chronological age, the acquisition of expressive vocabulary was delayed. However, considering the duration of hearing experience, most CI participants showed an earlier start and faster growth of expressive rather than receptive vocabulary in comparison with typically developing children. This quite atypical result persisted right up until the end of the follow-up. The acquisition of expressive grammar was delayed relative to chronological age, though all but one CI participant achieved the expected grammar level after approximately 3 years of CI use. In addition, the rate of grammar acquisition was not homogeneous during development, showing two different paces: one comparable with normal hearing in the transition from holophrastic to primitive combinatorial speech and a much slower one to attain more advanced levels of morphosyntactic control. From a rehabilitative viewpoint, our results suggest the importance of implementing rehabilitation in lexical comprehension, even when expressive vocabulary appears to be within normal range. Moreover, assessment of language acquisition in CI Italian children should focus on those grammar aspects that are more vulnerable to early acoustic deprivation (such as free and bound morphology) to ensure enhanced language therapy planning.

Effects of Lexical Characteristics and Demographic Factors on Mandarin Chinese Open-Set Word Recognition in Children With Cochlear Implants

The purpose of this study was to examine the open-set word recognition performance of Mandarin Chinese-speaking children who had received a multichannel cochlear implant (CI) and examine the effects of lexical characteristics and demographic factors (i.e., age at implantation and duration of implant use) on Mandarin Chinese open-set word recognition in these children. Participants were 230 prelingually deafened children with CIs. Age at implantation ranged from 0.9 to 16.0 years, with a mean of 3.9 years. The Standard-Chinese version of the Monosyllabic Lexical Neighborhood test and the Multisyllabic Lexical Neighborhood test were used to evaluate the open-set word identification abilities of the children. A two-way analysis of variance was performed to delineate the lexical effects on the open-set word identification, with word difficulty and syllable length as the two main factors. The effects of age at implantation and duration of implant use on open-set, word-recognition performance were examined using correlational/regressional models. First, the average percent-correct scores for the disyllabic "easy" list, disyllabic "hard" list, monosyllabic "easy" list, and monosyllabic "hard" list were 65.0%, 51.3%, 58.9%, and 46.2%, respectively. For both the easy and hard lists, the percentage of words correctly identified was higher for disyllabic words than for monosyllabic words, Second, the CI group scored 26.3%, 31.3%, and 18.8 % points lower than their hearing-age-matched normal-hearing peers for 4, 5, and 6 years of hearing age, respectively. The corresponding gaps between the CI group and the chronological-age-matched normal-hearing group were 47.6, 49.6, and 42.4, respectively. The individual variations in performance were much greater in the CI group than in the normal-hearing group, Third, the children exhibited steady improvements in performance as the duration of implant use increased, especially 1 to 6 years postimplantation. Last, age at implantation had significant effects on postimplantation word-recognition performance. The benefit of early implantation was particularly evident in children 5 years old or younger. First, Mandarin Chinese-speaking pediatric CI users' open-set word recognition was influenced by the lexical characteristics of the stimuli. The score was higher for easy words than for hard words and was higher for disyllabic words than for monosyllabic words, Second, Mandarin-Chinese-speaking pediatric CI users exhibited steady progress in open-set word recognition as the duration of implant use increased. However, the present study also demonstrated that, even after 6 years of CI use, there was a significant deficit in open-set, word-recognition performance in the CI children compared with their normal-hearing peers. Third, age at implantation had significant effects on open-set, word-recognition performance. Early implanted children exhibited better performance than children implanted later.