Years Of Cochlear Implant Experience Research Articles

Children with cochlear implant and additional disabilities benefit from consistent device use.

Although the prevalence of additional disabilities (AD) in children with a cochlear implant (CI) is high, children with such disabilities are often excluded from clinical studies, or their specific characteristics are only partially included. The literature shows that several factors need to be considered in evaluating auditory and language development in CI children with AD, including demographic variables as well as the severity and type of disability. Current findings on device use in children show correlations with auditory and language outcome, but little is known about device use specifically in children with AD. The purpose of this study was to determine the auditory and language outcome of CI children with AD and to analyse their datalogging-based daily device use, both 1 year and 2 years after implantation. In addition, any potential correlations between outcome and device use were to be identified. A cohort of 32 CI children with 5 different types of AD were included in this retrospective analysis. The children's auditory and language outcome was assessed by the parental questionnaires LittlEARS and ELFRA and by the professional observation tool CAP (Categories of Auditory Performance) 1 and 2 years after implantation. Longitudinal device use was analysed by using the CI system-integrated data-logging; daily duration of CI use, number of coil disconnections and exposure to different listening scenes were recorded. Overall, the cohort's auditory and language performance showed significant progress over time, while reduced abilities became more obvious after 2 years of CI experience. The mean daily duration of CI use increased significantly from 7.8±2.8 to 8.2±2.7h after 2 years. High numbers of daily coil disconnections were detected, with a significant mean decrease from 83.4±73.1 to 66.3±54.6 whereas the percentage exposure to different listening environments was widely stable over time. Significant rank correlations were identified between outcomes measured by ELFRA and CAP with daily duration of CI use, numbers of coil disconnections and percentage of exposure to speech-characterised listening scenes. The auditory and language outcome in CI children with AD is variable, but it progresses over time. Children benefit from a consistent daily device use as well as from a high exposure to speech-characterised environments. Device use should be monitored constantly, with particular focus on daily duration of CI use and, in particular, on the number of coil disconnections if children have a severe motor impairment. Objective data-logging is an important addition to outcome assessment by testing, observations and parental questionnaires. Although assessment in children with AD is a major challenge for professionals, comprehensive assessment is needed to improve cochlear implant services with special adaption to children with AD, and this should include audiological, development-related and psychosocial information. A unified system to classify types of disabilities could help to improve procedures for analysing different outcomes.

Evaluation of Automatic Directional Processing with Cochlear Implant Recipients.

For cochlear implant (CI) recipients, speech recognition in noise is consistently poorer compared with recognition in quiet. Directional processing improves performance in noise and can be automatically activated based on acoustic scene analysis. The use of adaptive directionality with CI recipients is new and has not been investigated thoroughly, especially utilizing the recipients' preferred everyday signal processing, dynamic range, and/or noise reduction. This study utilized CI recipients' preferred everyday signal processing to evaluate four directional microphone options in a noisy environment to determine which option provides the best speech recognition in noise. A greater understanding of automatic directionality could ultimately improve CI recipients' speech-in-noise performance and better guide clinicians in programming. Twenty-six unilateral and seven bilateral CI recipients with a mean age of 66 years and approximately 4 years of CI experience were included. Speech-in-noise performance was measured using eight loudspeakers in a 360-degree array with HINT sentences presented in restaurant noise. Four directional options were evaluated (automatic [SCAN], adaptive [Beam], fixed [Zoom], and Omni-directional) with participants' everyday use signal processing options active. A mixed-model analysis of variance (ANOVA) and pairwise comparisons were performed. Automatic directionality (SCAN) resulted in the best speech-in-noise performance, although not significantly better than Beam. Omni-directional performance was significantly poorer compared with the three other directional options. A varied number of participants performed their best with each of the four-directional options, with 16 performing best with automatic directionality. The majority of participants did not perform best with their everyday directional option. The individual variability seen in this study suggests that CI recipients try with different directional options to find their ideal program. However, based on a CI recipient's motivation to try different programs, automatic directionality is an appropriate everyday processing option.

Longer Cochlear Implant Experience Leads to Better Production of Mandarin Tones for Early Implanted Children.

Children with cochlear implants (CIs) face challenges in acquiring tones, since CIs do not transmit pitch information effectively. It has been suggested that longer CI experience provides additional benefits for children implanted early, enabling them to achieve language abilities similar to that of normal-hearing (NH) children (Colletti 2009). Mandarin is a tonal language with four lexical tones and a neutral tone (T0), characterized by distinct pitch and durational patterns. It has been suggested that early implantation (i.e., before 2 years) greatly benefits the acquisition of Mandarin tones by children with CIs (Tang et al. 2019c). In this study, we extend those findings to investigate the effect of CI experience on the acquisition of Mandarin tones for children implanted early. We asked the extent to which they were able to produce distinct pitch and durational patterns of both lexical tones and T0 as a function of CI experience, and the extent to which their tonal productions were acoustically like that of NH children. Forty-four NH 3-year olds and 28 children implanted with CIs between 1 and 2 years, aged 3 to 7, were recruited. The children with CIs were grouped according to the length of CI experience: 3 to 6 years, 2 to 3 years, and 1 to 2 years. Lexical tone and T0 productions were elicited using a picture-naming task. Tonal productions from the children with CIs were acoustically analyzed and compared with those from the NH children. Children with 3 to 6 years of CI experience were able to produce distinct pitch and durational patterns for both lexical tones and T0, with NH-like acoustic realizations. Children with 2 to 3 years of CI experience were also able to produce the expected tonal patterns, although their productions were not yet NH-like. Those with only 1 to 2 years of CI experience, however, were not yet able to produce the distinct acoustic patterns for either lexical tones or T0. These results provide acoustic evidence demonstrating that, when Mandarin-speaking children are implanted before the age of 2, only those with 3 to 6 years of experience were able to produce NH-like tones, including both lexical tone and T0. Children with shorter CI experience (less than 3 years) were unable to produce distinct acoustic patterns for the different tones. This suggests that at least 3 years of CI experience is still needed for early implanted children to acquire tonal distinctions similar to those of NH 3-year olds.

Assessment of Reliability and Validity of the Cochlear Implant Skills Review: A New Measure to Evaluate Cochlear Implant Users' Device Skills and Knowledge.

Purpose The Cochlear Implant Skills Review (CISR) was developed as a measure of cochlear implant (CI) users' skills and knowledge regarding device use. This study aimed to determine intra- and interrater reliability and agreement and establish construct validity for the CISR. Method In this study, the CISR was developed and administered to a cohort of 30 adult CI users. Participants included new CI users with less than 1 year of CI experience and experienced CI users with greater than 1 year of CI experience. The CISR administration required participants to demonstrate skills using the various features of their CI processors. Intra- and interrater reliability were assessed using intraclass correlation coefficients, agreement was assessed using Cohen's kappa, and construct validity was assessed by relating CISR performance to duration of CI use. Results Overall reliability for the entire instrument was 92.7%. Inter- and intrarater agreement were generally substantial or higher. Duration of CI use was a significant predictor of CISR performance. Conclusions The CISR is a reliable and valid assessment measure of device skills and knowledge for adult CI users. Clinicians can use this tool to evaluate areas of needed instruction and counseling and to assess users' skills over time.

Is the cochlear implant a successful long-term solution for single-sided deaf and asymmetric hearing-impaired patients?

PurposeWe investigated the long-term results of cochlear implant (CI) recipients with asymmetric hearing loss (AHL) or single-sided deafness (SSD). We focused on wearing behavior, audiometric hearing rehabilitation, and subjective benefits of the CI. CI is expected to improve audiological results, subjective hearing perception, and tinnitus burden.MethodsSpeech recognition in background noise and sound localization were assessed preoperatively and after at least six years of CI experience. Validated questionnaires determined the subjective benefit of CI use and the subjective evaluation of tinnitus.ResultsOver 80% of the included AHL and SSD CI recipients used their CI between 6 and 10 h daily; four subjects with SSD were non-users. Speech recognition in background noise and sound localization improved significantly compared with the unaided preoperative situation. Additionally, CI improved subjective speech intelligibility and spatial hearing impression while reducing tinnitus burden.ConclusionSubjects with AHL and SSD benefit from CI, subjectively and audiologically. Cochlear implant is a successful long-term treatment for AHL and SSD.

Electric-Acoustic Stimulation Outcomes in Children.

This study investigates outcomes in children fit with electric-acoustic stimulation (EAS) and addresses three main questions: (1) Are outcomes with EAS superior to outcomes with conventional electric-only stimulation in children? (2) Do children with residual hearing benefit from EAS and conventional electric-only stimulation when compared with the preoperative hearing aid (HA) condition? (3) Can children with residual hearing derive benefit from EAS after several years of listening with conventional electric-only stimulation? Sixteen pediatric cochlear implant (CI) recipients between 4 and 16 years of age with an unaided low-frequency pure tone average of 75 dB HL in the implanted ear were included in two study arms. Arm 1 included new recipients, and Arm 2 included children with at least 1 year of CI experience. Using a within-subject design, participants were evaluated unilaterally with the Consonant-Nucleus-Consonant (CNC) word list in quiet and the Baby Bio at a +5 dB SNR using an EAS program and a conventional full electric (FE) program. Arm 1 participants' scores were also compared with preoperative scores. Speech perception outcomes were statistically higher with the EAS program than the FE program. For new recipients, scores were significantly higher with EAS than preoperative HA scores for both the CNC and Baby Bio in noise; however, after 6 months of device use, results in the FE condition were not significantly better than preoperative scores. Long-term FE users benefited from EAS over their FE programs based on CNC word scores. Whether newly implanted or long-term CI users, children with residual hearing after CI surgery can benefit from EAS. Cochlear implantation with EAS fitting is a viable option for children with HAs who have residual hearing but have insufficient access to high-frequency sounds and poor speech perception.

Impaired Cognitive Functioning in Cochlear Implant Recipients Over the Age of 55 Years: A Cross-Sectional Study Using the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing-Impaired Individuals (RBANS-H).

Primary Objective: To compare cognitive functioning among experienced, unilateral cochlear implant (CI) recipients and normal-hearing (NH) controls by means of the Repeatable Battery for the Assessment of Neuropsychological Status for Hearing-impaired individuals (RBANS-H).Methods: Sixty-one post-lingually and bilaterally severely hearing-impaired CI recipients (median age: 71.0, range: 58.3 to 93.9 years) with at least 1 year of CI experience (median: 12.4, range: 1.1 to 18.6 years) and 81 NH control participants (median age: 69.9, range: 50.1 to 87.1 years) took part in this cross-sectional study. The RBANS-H was performed, as well as an audiometric assessment, including best-aided speech audiometry in quiet (monosyllabic words) and in noise (Leuven Intelligibility Sentences test).Results: The RBANS-H performances of the CI recipients (mean: 88.1 ± 14.9) were significantly poorer than the those of the NH participants (mean: 100.5 ± 13.2), with correction of age, sex, and education differences (general linear model: p = 0.001). The mean difference, corrected for the effects of these three demographic factors, was 8.8 (± 2.5) points. Additionally, in both groups, a significant correlation was established between overall cognition and speech perception, both in quiet and in noise, independently of age.Conclusion: Experienced, unilateral CI recipients present subnormal cognitive functioning, beyond the effect of age, sex and education. This has implications for auditory rehabilitation after CI and may highlight the need for additional cognitive rehabilitation in the long term after implantation. Long-term prospective and longitudinal investigations are imperative to improve our understanding of cognitive aging in severely hearing-impaired individuals receiving CIs and its association with CI outcomes.

Simultaneous bilateral cochlear implants: Developmental advances do not yet achieve normal cortical processing.

BackgroundSimultaneous bilateral cochlear implantation promotes symmetric development of bilateral auditory pathways but binaural hearing remains abnormal. To evaluate whether bilateral cortical processing remains impaired in such children, cortical activity to unilateral and bilateral stimuli was assessed in a unique cohort of 16 children who received bilateral cochlear implants (CIs) simultaneously at 1.97 ± 0.86 years of age and had ~4 years of CI experience, providing the first opportunity to assess electrically driven cortical development in the absence of reorganized asymmetries from sequential implantation.MethodsCortical activity to unilateral and bilateral stimuli was measured using multichannel electro‐encephalography. Cortical processing in children with bilateral CIs was compared with click‐elicited activity in 13 normal hearing children matched for time‐in‐sound. Source activity was localized using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer method.ResultsConsistent with dominant crossed auditory pathways, normal P1 activity (~100 ms) was weaker to ipsilateral stimuli relative to contralateral and bilateral stimuli and both auditory cortices preferentially responded to the contralateral ear. Right hemisphere dominance was evident overall. Children with bilateral CIs maintained the expected right dominance but differences from normal included: (i) minimal changes between ipsilateral, contralateral and bilateral stimuli, (ii) weaker than normal contralateral stimulus preference, (iii) symmetric activity to bilateral stimuli, and (iv) increased occipital lobe recruitment during bilateral relative to unilateral stimulation. Between‐group contrasts demonstrated lower than normal activity in the inferior parieto‐occipital lobe (suggesting deficits in sensory integration) and greater than normal left frontal lobe activity (suggesting increased attention), even during passive listening.ConclusionsTogether, findings suggest that early simultaneous bilateral cochlear implantation promotes normal‐like auditory symmetry but that abnormalities in cortical processing consequent to deafness and/or electrical stimulation through two independent speech processors persist.

The Acoustics of Word-Initial Fricatives and Their Effect on Word-Level Intelligibility in Children With Bilateral Cochlear Implants.

Previous research has found that relative to their peers with normal hearing (NH), children with cochlear implants (CIs) produce the sibilant fricatives /s/ and /∫/ less accurately and with less subphonemic acoustic contrast. The present study sought to further investigate these differences across groups in two ways. First, subphonemic acoustic properties were investigated in terms of dynamic acoustic features that indexed more than just the contrast between /s/ and /∫/. Second, the authors investigated whether such differences in subphonemic acoustic contrast between sibilant fricatives affected the intelligibility of sibilant-initial single word productions by children with CIs and their peers with NH. In experiment 1, productions of /s/ and /∫/ in word-initial prevocalic contexts were elicited from 22 children with bilateral CIs (aged 4 to 7 years) who had at least 2 years of CI experience and from 22 chronological age-matched peers with NH. Acoustic features were measured from 17 points across the fricatives: peak frequency was measured to index the place of articulation contrast; spectral variance and amplitude drop were measured to index the degree of sibilance. These acoustic trajectories were fitted with growth-curve models to analyze time-varying spectral change. In experiment 2, phonemically accurate word productions that were elicited in experiment 1 were embedded within four-talker babble and played to 80 adult listeners with NH. Listeners were asked to repeat the words, and their accuracy rate was used as a measure of the intelligibility of the word productions. Regression analyses were run to test which acoustic properties measured in experiment 1 predicted the intelligibility scores from experiment 2. The peak frequency trajectories indicated that the children with CIs produced less acoustic contrast between /s/ and /∫/. Group differences were observed in terms of the dynamic aspects (i.e., the trajectory shapes) of the acoustic properties. In the productions by children with CIs, the peak frequency and the amplitude drop trajectories were shallower, and the spectral variance trajectories were more asymmetric, exhibiting greater increases in variance (i.e., reduced sibilance) near the fricative-vowel boundary. The listeners' responses to the word productions indicated that when produced by children with CIs, /∫/-initial words were significantly more intelligible than /s/-initial words. However, when produced by children with NH, /s/-initial words and /∫/-initial words were equally intelligible. Intelligibility was partially predicted from the acoustic properties (Cox & Snell pseudo-R > 0.190), and the significant predictors were predominantly dynamic, rather than static, ones. Productions from children with CIs differed from those produced by age-matched NH controls in terms of their subphonemic acoustic properties. The intelligibility of sibilant-initial single-word productions by children with CIs is sensitive to the place of articulation of the initial consonant (/∫/-initial words were more intelligible than /s/-initial words), but productions by children with NH were equally intelligible across both places of articulation. Therefore, children with CIs still exhibit differential production abilities for sibilant fricatives at an age when their NH peers do not.

Early Expressive Language Skills Predict Long-Term Neurocognitive Outcomes in Cochlear Implant Users: Evidence from the MacArthur-Bates Communicative Development Inventories.

The objective of the present article was to document the extent to which early expressive language skills (measured using the MacArthur-Bates Communicative Development Inventories [CDI; Fenson et al., 2006]) predict long-term neurocognitive outcomes in a sample of early-implanted prelingually deaf cochlear implant (CI) users. The CDI was used to index the early expressive language skills of 32 pediatric CI users after an average of 1.03 years (SD = 0.56, range = 0.39-2.17) of CI experience. Long-term neurocognitive outcomes were assessed after an average of 11.32 (SD = 2.54, range = 7.08-16.52) years of CI experience. Measures of long-term neurocognitive outcomes were derived from gold-standard performance-based and questionnaire-based assessments of language, executive functioning, and academic skills. Analyses revealed that early expressive language skills, collected on average 1.03 years post cochlear implantation, predicted long-term language, executive functioning, and academic skills up to 16 years later. These findings suggest that early expressive language skills, as indexed by the CDI, are clinically relevant for identifying CI users who may be at high risk for long-term neurocognitive delays and disturbances.

Peripheral and Central Contributions to Cortical Responses in Cochlear Implant Users.

The primary goal of this study was to describe relationships between peripheral and central electrophysiologic measures of auditory processing within individual cochlear implant (CI) users. The distinctiveness of neural excitation patterns resulting from the stimulation of different electrodes, referred to as 'spatial selectivity,' was evaluated. The hypothesis was that if central representations of spatial interactions differed across participants semi-independently of peripheral input, then the within-subject relationships between peripheral and central electrophysiologic measures of spatial selectivity would reflect those differences. Cross-subject differences attributable to processing central to the auditory nerve may help explain why peripheral electrophysiologic measures of spatial selectivity have not been found to correlate with speech perception. Eleven adults participated in this and a companion study. All were peri- or post-lingually deafened with more than 1 year of CI experience. Peripheral spatial selectivity was evaluated at 13 cochlear locations using 13 electrodes as probes to elicit electrically evoked compound action potentials (ECAPs). Masker electrodes were varied across the array for each probe electrode to derive channel-interaction functions. The same 13 electrodes were used to evaluate spatial selectivity represented at a cortical level. Electrode pairs were stimulated sequentially to elicit the auditory change complex (ACC), an obligatory cortical potential suggestive of discrimination. For each participant, the relationship between ECAP channel-interaction functions (quantified as channel-separation indices) and ACC N1-P2 amplitudes was modeled using the saturating exponential function y = a * (1-e). Both a and b coefficients were varied using a least-squares approach to optimize the fits. Electrophysiologic measures of spatial selectivity assessed at peripheral (ECAP) and central (ACC) levels varied across participants. The results indicate that differences in ACC amplitudes observed across participants for the same stimulus conditions were not solely the result of differences in peripheral excitation patterns. This finding supports the view that processing at multiple points along the auditory neural pathway from the periphery to the cortex may vary across individuals with different etiologies and auditory experiences. The distinctiveness of neural excitation resulting from electrical stimulation varies across CI recipients, and this variability was observed in both peripheral and cortical electrophysiologic measures. The ACC amplitude differences observed across participants were partially independent from differences in peripheral neural spatial selectivity. These findings are clinically relevant because they imply that there may be limits (1) to the predictive ability of peripheral measures and (2) in the extent to which improving the selectivity of electrical stimulation via programming options (e.g., current focusing/steering) will result in more specific central neural excitation patterns or will improve speech perception.

Environmental sound training in cochlear implant users.

The study investigated the effect of a short computer-based environmental sound training regimen on the perception of environmental sounds and speech in experienced cochlear implant (CI) patients. Fourteen CI patients with the average of 5 years of CI experience participated. The protocol consisted of 2 pretests, 1 week apart, followed by 4 environmental sound training sessions conducted on separate days in 1 week, and concluded with 2 posttest sessions, separated by another week without training. Each testing session included an environmental sound test, which consisted of 40 familiar everyday sounds, each represented by 4 different tokens, as well as the Consonant Nucleus Consonant (CNC) word test, and Revised Speech Perception in Noise (SPIN-R) sentence test. Environmental sounds scores were lower than for either of the speech tests. Following training, there was a significant average improvement of 15.8 points in environmental sound perception, which persisted 1 week later after training was discontinued. No significant improvements were observed for either speech test. The findings demonstrate that environmental sound perception, which remains problematic even for experienced CI patients, can be improved with a home-based computer training regimen. Such computer-based training may thus provide an effective low-cost approach to rehabilitation for CI users, and potentially, other hearing impaired populations.

Self-Assessment of Hearing Disabilities in Cochlear Implant Users Using the SSQ and the Reduced SSQ5 Version

Routine clinical assessment to evaluate the hearing performance in a cochlear implant (CI) population should include individual self-assessment tools. Because of pragmatic and psychometric considerations, there's a growing need for reduced self-assessment questionnaires. The aim of the study is twofold. First, the study aims to ascertain a disability profile, using the Speech, Spatial and Qualities of Hearing Scale (SSQ), in a CI population and to compare this profile with a hearing impaired group with similar average hearing thresholds. The second aim of the study is to investigate the degree of agreement between the total SSQ scores and the total scores of the reduced 5-item version of the SSQ, namely, the SSQ5. This cross-sectional study uses the SSQ obtained from CI patients from the Ear, Nose and Throat (ENT) department of the Antwerp University Hospital. Fifty-four postlingually deaf CI patients completed the SSQ questionnaire. All subjects were implanted with a CI at an average age of 55 years. At the time they completed the questionnaire, they had, on average, 3 (SD, 3) years of CI experience. To determine the disability profile in a CI population, the following criteria were assayed: standard values, internal consistency, sensitivity, and floor (or ceiling) effects of the SSQ. These criteria were compared with those of a hearing-impaired group (n = 153) reported in the original study.Second, Spearman correlations coefficients and intraclass correlations coefficients (ICCs) were used to determine the degree of agreement between the total SSQ scores and the total SSQ5 scores. Analysis of internal consistency, sensitivity, and floor and ceiling effects showed that self-assessment using the SSQ is feasible in a CI population. The obtained disability profile presents a mean total SSQ(C I group) of 4:25 ( S D = 1:65). When comparing item results, significant differences were found between CI users and moderate hearing-impaired patients (SSQ(hearing impaired group) = 5.5; S D1:9). Intraclass correlation (ICC = 0.78; p < 0.01) and Spearman correlations coefficients (R = 0.77; p < 0.01) indicate a significantly high degree of agreement between the total SSQ scores and the total SSQ5 scores. This article shows the disability profile in a CI population, using SSQ. Significant differences regarding dynamic aspects of hearing between CI users and moderate hearing-impaired patients were found, to the detriment of the CI users. The static aspects of hearing represented in the Speech section, on the other hand, showed more similarities. The reduced 5-item version of the SSQ, namely, the SSQ5, is robust to effectively measure evolutions in hearing (dis)abilities in CI users.

Beginning to Talk Like an Adult: Increases in Speech-Like Utterances in Young Cochlear Implant Recipients and Typically Developing Children

Speech-like utterances containing rapidly combined consonants and vowels eventually dominate the prelinguistic and early word productions of typically developing (TD) toddlers. It seems reasonable to expect a similar phenomenon in young recipients of cochlear implants (CIs). The authors of this study sought to determine the number of months of robust hearing experience needed to achieve a majority of speech-like utterances in both of these groups. Speech samples were recorded from CI recipients at 3-month intervals during the first 2 years of CI experience, and from TD children at time points between 6 and 24 months of age. Speech-like utterances were operationally defined as those belonging to the basic canonical syllables (BCS) or advanced forms (AF) levels of the Consolidated Stark Assessment of Early Vocal Development-Revised ( Ertmer, Young, & Nathani, 2007). On average, the CI group achieved a majority of speech-like utterances after 12 months of robust hearing experience and the TD group after 18 months. The CI group produced greater percentages of speech-like utterances at each interval until 24 months, when both groups approximated 80%. Auditory deprivation did not limit progress in vocal development as young CI recipients showed more-rapid-than-typical speech development during the first 2 years of device use. Implications for the infraphonological model of speech development are considered.

Consonant Production Accuracy in Young Cochlear Implant Recipients: Developmental Sound Classes and Word Position Effects

To compare young cochlear implant (CI) recipients' consonant production accuracy with that of age- and gender-matched peers who were typically developing (TD). In addition to examining initial consonants, the authors compiled new data regarding the accuracy of final consonants and the order of consonant acquisition. Eleven young CI recipients with 24 months of CI experience and 11 age- and gender-matched TD peers produced target words in short sentences. Consonant production accuracy was examined for total scores, initial and final word positions, and three developmental sound classes: Early, Middle, and Late. Initial consonants were produced with relatively greater accuracy than were final consonants by the TD and CI groups. Whereas initial consonants appeared to be acquired in a typical order, descriptive data suggest that this might not be the case for final consonants. Although still delayed compared to age-matched peers, young CI recipients showed substantial progress in consonant acquisition. Their accuracy levels after 2 years of CI experience support the notion that implantation at a young age has added value for phonological development.

Psychoacoustic Performance and Music and Speech Perception in Prelingually Deafened Children with Cochlear Implants

The number of pediatric cochlear implant (CI) recipients has increased substantially over the past 10 years, and it has become more important to understand the underlying mechanisms of the variable outcomes in this population. In this study, psychoacoustic measures of spectral-ripple and Schroeder-phase discrimination, the Clinical Assessment of Music Perception, and consonant-nucleus-consonant (CNC) word recognition in quiet and spondee reception threshold (SRT) in noise tests have been presented to 11 prelingually deafened CI users, aged 8–16 years with at least 5 years of CI experience. The children’s performance was compared to the previously reported results of postlingually deafened adult CI users. The average spectral-ripple threshold (n = 10) was 2.08 ripples/octave. The average Schroeder-phase discrimination was 67.3% for 50 Hz and 56.5% for 200 Hz (n = 9). The Clinical Assessment of Music Perception test showed that the average complex pitch direction discrimination was 2.98 semitones. The mean melody score was at a chance level, and the mean timbre score was 34.1% correct. The mean CNC word recognition score was 68.6%, and the mean SRT in steady noise was –8.5 dB SNR. The children’s spectral-ripple resolution, CNC word recognition, and SRT in noise performances were, within statistical bounds, the same as in a population of postlingually deafened adult CI users. However, Schroeder-phase discrimination and music perception were generally poorer than in the adults. It is possible then that this poorer performance seen in the children might be partly accounted for by the delayed maturation in their temporal processing ability, and because of this, the children’s performance may have been driven more by their spectral sensitivity.

Measures of digit span and verbal rehearsal speed in deaf children after more than 10 years of cochlear implantation.

Conventional assessments of outcomes in deaf children with cochlear implants (CIs) have focused primarily on endpoint or product measures of speech and language. Little attention has been devoted to understanding the basic underlying core neurocognitive factors involved in the development and processing of speech and language. In this study, we examined the development of factors related to the quality of phonological information in immediate verbal memory, including immediate memory capacity and verbal rehearsal speed, in a sample of deaf children after >10 yrs of CI use and assessed the correlations between these two process measures and a set of speech and language outcomes. Of an initial sample of 180 prelingually deaf children with CIs assessed at ages 8 to 9 yrs after 3 to 7 yrs of CI use, 112 returned for testing again in adolescence after 10 more years of CI experience. In addition to completing a battery of conventional speech and language outcome measures, subjects were administered the Wechsler Intelligence Scale for Children-III Digit Span subtest to measure immediate verbal memory capacity. Sentence durations obtained from the McGarr speech intelligibility test were used as a measure of verbal rehearsal speed. Relative to norms for normal-hearing children, Digit Span scores were well below average for children with CIs at both elementary and high school ages. Improvement was observed over the 8-yr period in the mean longest digit span forward score but not in the mean longest digit span backward score. Longest digit span forward scores at ages 8 to 9 yrs were significantly correlated with all speech and language outcomes in adolescence, but backward digit spans correlated significantly only with measures of higher-order language functioning over that time period. While verbal rehearsal speed increased for almost all subjects between elementary grades and high school, it was still slower than the rehearsal speed obtained from a control group of normal-hearing adolescents. Verbal rehearsal speed at ages 8 to 9 yrs was also found to be strongly correlated with speech and language outcomes and Digit Span scores in adolescence. Despite improvement after 8 additional years of CI use, measures of immediate verbal memory capacity and verbal rehearsal speed, which reflect core fundamental information processing skills associated with representational efficiency and information processing capacity, continue to be delayed in children with CIs relative to NH peers. Furthermore, immediate verbal memory capacity and verbal rehearsal speed at 8 to 9 yrs of age were both found to predict speech and language outcomes in adolescence, demonstrating the important contribution of these processing measures for speech-language development in children with CIs. Understanding the relations between these core underlying processes and speech-language outcomes in children with CIs may help researchers to develop new approaches to intervention and treatment of deaf children who perform poorly with their CIs. Moreover, this knowledge could be used for early identification of deaf children who may be at high risk for poor speech and language outcomes after cochlear implantation as well as for the development of novel targeted interventions that focus selectively on these core elementary information processing variables.

Speech Production Accuracy and Variability in Young Cochlear Implant Recipients: Comparisons With Typically Developing Age-Peers

The speech production accuracy and variability scores of 6 young cochlear implant (CI) recipients with 2 years of device experience were compared with those of typically developing (TD) age-peers. Words from the First Words Speech Test (FWST; Ertmer, 1999) were imitated 3 times to assess the accuracy and variability of initial consonants, vowels, and words. The initial consonants in the 4 sets of the FWST followed a typical order of development. The TD group produced targets with high accuracy and low variability. Their scores across FWST sets reflected the expected order of development. The CI group produced most targets less accurately and with more variability than the TD children. Relatively high accuracy for the consonants of Sets 1 and 2 indicated that these phonemes were acquired early and in a typical developmental order. A trend toward greater accuracy for Set 4 as compared with Set 3 suggested that later-emerging consonants were not acquired in the expected order. Variability was greatest for later-emerging initial consonants and whole words. Although considerable speech production proficiency was evident, age-level performance was not attained after 2 years of CI experience. Factors that might influence the order of consonant acquisition are discussed.

Validation of the Common Objects Token (COT) Test for Children With Cochlear Implants

Changes in selection criteria have meant that children are being provided with cochlear implants (CI) at increasingly younger ages. However, there is a paucity of measures that are appropriate for testing complex listening skills — most tests are too cognitively complex for such young children. The Common Objects Token (COT) Test was developed as a complex closed-set test for children with profound hearing losses. This test was assessed for its usefulness in assessing children with cochlear implants. The test was administered to 20 implanted children over a period of two months. Results indicated that some subtests were equal and there was not a hierarchical subtest order. Based on these findings, the test was modified and then re-assessed on 85 children. Outcomes showed that all subtests assessed the same construct. Two subtests were able to predict the total score of the COT test. The test was modified to include two levels, one with easier tests suitable for younger children, and a shorter, quicker version for instances where there may be attention span or time constraints. Outcomes showed that the test may be suitable for children aged three and above and that children with less than two years of CI experience are able to perform on the test. The results of this testing indicated that the COT test is a useful addition to the test battery for assessing young implanted children. Copyright © 2005 John Wiley & Sons, Ltd.