Effects of Segmental and Suprasegmental Speech Perception on Reading in Pediatric Cochlear Implant Recipients.

PURPOSE: The aim of this study was to determine whether suprasegmental speech perception contributes unique variance in predictions of reading decoding and comprehension for prelingually deaf children using two devices, at least one of which is a cochlear implant (CI). METHOD: A total of 104, 5- to 9-year-old CI recipients completed tests of segmental perception (e.g., word recognition in quiet and noise, recognition of vowels and consonants in quiet), suprasegmental perception (e.g., talker and stress discrimination, nonword stress repetition, and emotion identification), and nonverbal intelligence. Two years later, participants completed standardized tests of reading decoding and comprehension. Using regression analyses, the unique contribution of suprasegmental perception to reading skills was determined after controlling for demographic characteristics and segmental perception performance. RESULTS: Standardized reading scores of the CI recipients increased with nonverbal intelligence for both decoding and comprehension. Female gender was associated with higher comprehension scores. After controlling for gender and nonverbal intelligence, segmental perception accounted for approximately 4% and 2% of the variance in decoding and comprehension, respectively. After controlling for nonverbal intelligence, gender, and segmental perception, suprasegmental perception accounted for an extra 4% and 7% unique variance in reading decoding and reading comprehension, respectively. CONCLUSIONS: Suprasegmental perception operates independently from segmental perception to facilitate good reading outcomes for these children with CIs. Clinicians and educators should be mindful that early perceptual skills may have long-term benefits for literacy. Research on how to optimize suprasegmental perception, perhaps through hearing-device programming and/or training strategies, is needed.

Spectral Modulation Detection Performance and Speech Perception in Pediatric Cochlear Implant Recipients.

PURPOSE: The aims of this study were, for pediatric cochlear implant (CI) recipients, (a) to determine the effect of age on their spectral modulation detection (SMD) ability and compare their age effect to that of their typically hearing (TH) peers; (b) to identify demographic, cognitive, and audiological factors associated with SMD ability; and (c) to determine the unique contribution of SMD ability to segmental and suprasegmental speech perception performance. METHOD: A total of 104 pediatric CI recipients and 38 TH peers (ages 6-11 years) completed a test of SMD. CI recipients completed tests of segmental (e.g., word recognition in noise and vowels and consonants in quiet) and suprasegmental (e.g., talker discrimination, stress discrimination, and emotion identification) perception, nonverbal intelligence, and working memory. Regressions analyses were used to examine the effects of group and age on percent-correct SMD scores. For the CI group, the effects of demographic, audiological, and cognitive variables on SMD performance and the effects of SMD on speech perception were examined. RESULTS: The TH group performed significantly better than the CI group on SMD. Both groups showed better performance with increasing age. Significant predictors of SMD performance for the CI group were age and nonverbal intelligence. SMD performance predicted significant variance in segmental and suprasegmental perception. The variance predicted by SMD performance was nearly double for suprasegmental than for segmental perception. CONCLUSIONS: Children in the CI group, on average, scored lower than their TH peers. The slopes of improvement in SMD with age did not differ between the groups. The significant effect of nonverbal intelligence on SMD performance in CI recipients indicates that difficulties inherent in the task affect outcomes. SMD ability predicted speech perception scores, with a more prominent role in suprasegmental than in segmental speech perception. SMD ability may provide a useful nonlinguistic tool for predicting speech perception benefit, with cautious interpretation based on age and cognitive function.

Effects of Early Acoustic Hearing on Speech Perception and Language for Pediatric Cochlear Implant Recipients.

Purpose The overall goal of the current study was to identify an optimal level and duration of acoustic experience that facilitates language development for pediatric cochlear implant (CI) recipients-specifically, to determine whether there is an optimal duration of hearing aid (HA) use and unaided threshold levels that should be considered before proceeding to bilateral CIs. Method A total of 117 pediatric CI recipients (ages 5-9 years) were given speech perception and standardized tests of receptive vocabulary and language. The speech perception battery included tests of segmental perception (e.g., word recognition in quiet and noise, and vowels and consonants in quiet) and of suprasegmental perception (e.g., talker and stress discrimination, and emotion identification). Hierarchical regression analyses were used to determine the effects of speech perception on language scores, and the effects of residual hearing level (unaided pure-tone average [PTA]) and duration of HA use on speech perception. Results A continuum of residual hearing levels and the length of HA use were represented by calculating the unaided PTA of the ear with the longest duration of HA use for each child. All children wore 2 devices: Some wore bimodal devices, while others received their 2nd CI either simultaneously or sequentially, representing a wide range of HA use (0.03-9.05 years). Regression analyses indicate that suprasegmental perception contributes unique variance to receptive language scores and that both segmental and suprasegmental skills each contribute independently to receptive vocabulary scores. Also, analyses revealed an optimal duration of HA use for each of 3 ranges of hearing loss severity (with mean PTAs of 73, 92, and 111 dB HL) that maximizes suprasegmental perception. Conclusions For children with the most profound losses, early bilateral CIs provide the greatest opportunity for developing good spoken language skills. For those with moderate-to-severe losses, however, a prescribed period of bimodal use may be more advantageous for developing good spoken language skills.

Effects of Early Auditory Deprivation on Working Memory and Reasoning Abilities in Verbal and Visuospatial Domains for Pediatric Cochlear Implant Recipients.

OBJECTIVES: The overall goal of this study was to compare verbal and visuospatial working memory in children with normal hearing (NH) and with cochlear implants (CI). The main questions addressed by this study were (1) Does auditory deprivation result in global or domain-specific deficits in working memory in children with CIs compared with their NH age mates? (2) Does the potential for verbal recoding affect performance on measures of reasoning ability in children with CIs relative to their NH age mates? and (3) Is performance on verbal and visuospatial working memory tasks related to spoken receptive language level achieved by children with CIs? DESIGN: A total of 54 children ranging in age from 5 to 9 years participated; 25 children with CIs and 29 children with NH. Participants were tested on both simple and complex measures of verbal and visuospatial working memory. Vocabulary was assessed with the Peabody Picture Vocabulary Test (PPVT) and reasoning abilities with two subtests of the WISC-IV (Wechsler Intelligence Scale for Children, 4th edition): Picture Concepts (verbally mediated) and Matrix Reasoning (visuospatial task). Groups were compared on all measures using analysis of variance after controlling for age and maternal education. RESULTS: Children with CIs scored significantly lower than children with NH on measures of working memory, after accounting for age and maternal education. Differences between the groups were more apparent for verbal working memory compared with visuospatial working memory. For reasoning and vocabulary, the CI group scored significantly lower than the NH group for PPVT and WISC Picture Concepts but similar to NH age mates on WISC Matrix Reasoning. CONCLUSIONS: Results from this study suggest that children with CIs have deficits in working memory related to storing and processing verbal information in working memory. These deficits extend to receptive vocabulary and verbal reasoning and remain even after controlling for the higher maternal education level of the NH group. Their ability to store and process visuospatial information in working memory and complete reasoning tasks that minimize verbal labeling of stimuli more closely approaches performance of NH age mates.

Assessing consonant production in children with cochlear implants.

OBJECTIVE: The objective of this study was to investigate the development of consonant inventory and accuracy in pediatric cochlear implant (CI) recipients and compare their performance to typical hearing (TH) children. METHODS: One hundred and twenty nine children with CIs, implanted between 6-38 months of age, and 30 age-matched children with TH participated in this study. Spontaneous speech samples were collected at 3.5 and 4.5 years chronological age and the first 100 different words spoken by each participant were transcribed. Two consonant production measures were subsequently calculated to assess consonant acquisition and mastery. The percentage of Consonants Correct (CC) was used for measuring accuracy and Consonant Diversity (CD), an inventory measure, was used to identify the number of different consonants spoken by each participant. Repeated measures analyses of variance were conducted to examine the differences in consonant production scores based on presence of CI (participants with CI versus typical hearing (TH) participants), and chronological age at data collection (3.5 years versus 4.5 years). RESULTS: CI recipients displayed lower consonant production scores compared to TH children. Children with the most device experience (32-38 months at 3.5 years) performed on par with their TH peers. CONCLUSIONS: The two measures used in this study together appear capable of comprehensively describing the changes in consonant production skills of children. Results from this study indicate that while most CI participants display lower scores compared to TH children, many of the CI users are able to produce speech sounds on par with TH children.

Sensitivity of expressive linguistic domains to surgery age and audibility of speech in preschoolers with cochlear implants.

OBJECTIVES: To determine whether relative delays among domains exist in the conversational use of vocabulary, syntax, and morphology by children with cochlear implants (CIs) and whether these were differentially affected by age of implantation (AOI) and the audibility of speech. METHODS: Participants in this short-term longitudinal study were 126 children with AOI of 6-38 months and a matched group of 30 children without hearing loss. Language samples of the same children at ages 3.5 and 4.5 were analyzed for the breadth of vocabulary and bound morphemes used, and sentence length. RESULTS: At both test ages, expressive language domains were delayed equally. Higher performance across domains was independently associated with younger AOI and better pre-implant-aided thresholds. No domain was affected differently by very early implantation, but bound morpheme breadth was associated with better CI-aided thresholds. Between 63 and 78% of children with AOI of 6-11 months scored close to hearing age-mates by 4.5, a level achieved by fewer than 25% of those with AOI of 19-24 months or later ages. DISCUSSION: Previous studies indicated greater language delays in the areas of morphology and syntax than those of vocabulary, with the earliest ages of implantation conferring the greatest benefit to those domains. The current design addressed inconsistency across studies in modes of communication used, presence/absence of other disabilities, and differences in language domains chosen as outcome measures. CONCLUSIONS: Linguistic domains benefitted equally from early implantation, regardless of the duration of auditory stimulation. Better pre-CI-aided hearing often compensated for later AOI. Bound morpheme use was greater with better CI-aided thresholds.

Early Sign Language Exposure and Cochlear Implantation Benefits.

BACKGROUND: Most children with hearing loss who receive cochlear implants (CI) learn spoken language, and parents must choose early on whether to use sign language to accompany speech at home. We address whether parents' use of sign language before and after CI positively influences auditory-only speech recognition, speech intelligibility, spoken language, and reading outcomes. METHODS: Three groups of children with CIs from a nationwide database who differed in the duration of early sign language exposure provided in their homes were compared in their progress through elementary grades. The groups did not differ in demographic, auditory, or linguistic characteristics before implantation. RESULTS: Children without early sign language exposure achieved better speech recognition skills over the first 3 years postimplant and exhibited a statistically significant advantage in spoken language and reading near the end of elementary grades over children exposed to sign language. Over 70% of children without sign language exposure achieved age-appropriate spoken language compared with only 39% of those exposed for 3 or more years. Early speech perception predicted speech intelligibility in middle elementary grades. Children without sign language exposure produced speech that was more intelligible (mean = 70%) than those exposed to sign language (mean = 51%). CONCLUSIONS: This study provides the most compelling support yet available in CI literature for the benefits of spoken language input for promoting verbal development in children implanted by 3 years of age. Contrary to earlier published assertions, there was no advantage to parents' use of sign language either before or after CI.

Persistent Language Delay Versus Late Language Emergence in Children With Early Cochlear Implantation.

PURPOSE: The purpose of the present investigation is to differentiate children using cochlear implants (CIs) who did or did not achieve age-appropriate language scores by midelementary grades and to identify risk factors for persistent language delay following early cochlear implantation. MATERIALS AND METHOD: Children receiving unilateral CIs at young ages (12-38 months) were tested longitudinally and classified with normal language emergence (n = 19), late language emergence (n = 22), or persistent language delay (n = 19) on the basis of their test scores at 4.5 and 10.5 years of age. Relative effects of demographic, audiological, linguistic, and academic characteristics on language emergence were determined. RESULTS: Age at CI was associated with normal language emergence but did not differentiate late emergence from persistent delay. Children with persistent delay were more likely to use left-ear implants and older speech processor technology. They experienced higher aided thresholds and lower speech perception scores. Persistent delay was foreshadowed by low morphosyntactic and phonological diversity in preschool. Logistic regression analysis predicted normal language emergence with 84% accuracy and persistent language delay with 74% accuracy. CONCLUSION: CI characteristics had a strong effect on persistent versus resolving language delay, suggesting that right-ear (or bilateral) devices, technology upgrades, and improved audibility may positively influence long-term language outcomes.

The effects of audibility and novel word learning ability on vocabulary level in children with cochlear implants.

OBJECTIVES: A novel word learning (NWL) paradigm was used to explore underlying phonological and cognitive mechanisms responsible for delayed vocabulary level in children with cochlear implants (CIs). METHODS: One hundred and one children using CIs, 6-12 years old, were tested along with 47 children with normal hearing (NH). Tests of NWL, receptive vocabulary, and speech perception at 2 loudness levels were administered to children with CIs. Those with NH completed the NWL task and a receptive vocabulary test. CI participants with good audibility (GA) versus poor audibility (PA) were compared on all measures. Analysis of variance was used to compare performance across the children with NH and the two groups of children with CIs. Multiple regression analysis was employed to identify independent predictors of vocabulary outcomes. RESULTS: Children with CIs in the GA group scored higher in receptive vocabulary and NWL than children in the PA group, although they did not reach NH levels. CI-aided pure tone threshold and performance on the NWL task predicted independent variance in vocabulary after accounting for other known predictors. DISCUSSION: Acquiring spoken vocabulary is facilitated by GA with a CI and phonological learning and memory skills. Children with CIs did not learn novel words at the same rate or achieve the same receptive vocabulary levels as their NH peers. Maximizing audibility for the perception of speech and direct instruction of new vocabulary may be necessary for children with CIs to reach levels seen in peers with NH.

Interdependence of linguistic and indexical speech perception skills in school-age children with early cochlear implantation.

OBJECTIVES: This study documented the ability of experienced pediatric cochlear implant (CI) users to perceive linguistic properties (what is said) and indexical attributes (emotional intent and talker identity) of speech, and examined the extent to which linguistic (LSP) and indexical (ISP) perception skills are related. Preimplant-aided hearing, age at implantation, speech processor technology, CI-aided thresholds, sequential bilateral cochlear implantation, and academic integration with hearing age-mates were examined for their possible relationships to both LSP and ISP skills. DESIGN: Sixty 9- to 12-year olds, first implanted at an early age (12 to 38 months), participated in a comprehensive test battery that included the following LSP skills: (1) recognition of monosyllabic words at loud and soft levels, (2) repetition of phonemes and suprasegmental features from nonwords, and (3) recognition of key words from sentences presented within a noise background, and the following ISP skills: (1) discrimination of across-gender and within-gender (female) talkers and (2) identification and discrimination of emotional content from spoken sentences. A group of 30 age-matched children without hearing loss completed the nonword repetition, and talker- and emotion-perception tasks for comparison. RESULTS: Word-recognition scores decreased with signal level from a mean of 77% correct at 70 dB SPL to 52% at 50 dB SPL. On average, CI users recognized 50% of key words presented in sentences that were 9.8 dB above background noise. Phonetic properties were repeated from nonword stimuli at about the same level of accuracy as suprasegmental attributes (70 and 75%, respectively). The majority of CI users identified emotional content and differentiated talkers significantly above chance levels. Scores on LSP and ISP measures were combined into separate principal component scores and these components were highly correlated (r = 0.76). Both LSP and ISP component scores were higher for children who received a CI at the youngest ages, upgraded to more recent CI technology and had lower CI-aided thresholds. Higher scores, for both LSP and ISP components, were also associated with higher language levels and mainstreaming at younger ages. Higher ISP scores were associated with better social skills. CONCLUSIONS: Results strongly support a link between indexical and linguistic properties in perceptual analysis of speech. These two channels of information appear to be processed together in parallel by the auditory system and are inseparable in perception. Better speech performance, for both linguistic and indexical perception, is associated with younger age at implantation and use of more recent speech processor technology. Children with better speech perception demonstrated better spoken language, earlier academic mainstreaming, and placement in more typically sized classrooms (i.e., >20 students). Well-developed social skills were more highly associated with the ability to discriminate the nuances of talker identity and emotion than with the ability to recognize words and sentences through listening. The extent to which early cochlear implantation enabled these early-implanted children to make use of both linguistic and indexical properties of speech influenced not only their development of spoken language, but also their ability to function successfully in a hearing world.

Spoken language benefits of extending cochlear implant candidacy below 12 months of age.

OBJECTIVE: To test the hypothesis that cochlear implantation surgery before 12 months of age yields better spoken language results than surgery between 12 and 18 months of age. STUDY DESIGN: Language testing administered to children at 4.5 years of age (± 2 mo). SETTING: Schools, speech-language therapy offices, and cochlear implant (CI) centers in the United States and Canada. PARTICIPANTS: Sixty-nine children who received a cochlear implant between ages 6 and 18 months of age. All children were learning to communicate via listening and spoken language in English-speaking families. MAIN OUTCOME MEASURE: Standard scores on receptive vocabulary, expressive, and receptive language (includes grammar). RESULTS: Children with CI surgery at 6 to 11 months (n = 27) achieved higher scores on all measures as compared with those with surgery at 12 to 18 months (n = 42). Regression analysis revealed a linear relationship between age of implantation and language outcomes throughout the 6- to 18-month surgery-age range. CONCLUSION: For children in intervention programs emphasizing listening and spoken language, cochlear implantation before 12 months of age seems to provide a significant advantage for spoken language achievement observed at 4.5 years of age.

Enduring advantages of early cochlear implantation for spoken language development.

PURPOSE: In this article, the authors sought to determine whether the precise age of implantation (AOI) remains an important predictor of spoken language outcomes in later childhood for those who received a cochlear implant (CI) between 12 and 38 months of age. Relative advantages of receiving a bilateral CI after age 4.5 years, better pre-CI-aided hearing, and longer CI experience were also examined. METHOD: Sixty children participated in a prospective longitudinal study of outcomes at 4.5 and 10.5 years of age. Twenty-nine children received a sequential second CI. Test scores were compared with normative samples of hearing age mates, and predictors of outcomes were identified. RESULTS: Standard scores on language tests at 10.5 years of age remained significantly correlated with age of first cochlear implantation. Scores were not associated with receipt of a second, sequentially acquired CI. Significantly higher scores were achieved for vocabulary as compared with overall language, a finding not evident when the children were tested at younger ages. CONCLUSION: Age-appropriate spoken language skills continued to be more likely with younger AOI, even after an average of 8.6 years of additional CI use. Receipt of a second implant between ages 4 and 10 years and longer duration of device use did not provide significant added benefit.

A longitudinal study of speech perception skills and device characteristics of adolescent cochlear implant users.

BACKGROUND: For pediatric cochlear implant (CI) users, CI processor technology, map characteristics, and fitting strategies are known to have a substantial impact on speech perception scores at young ages. It is unknown whether these benefits continue over time as these children reach adolescence. PURPOSE: To document changes in CI technology, map characteristics, and speech perception scores in children between elementary grades and high school, and to describe relations between map characteristics and speech perception scores over time. RESEARCH DESIGN: A longitudinal design with participants 8-9-yr-old at session 1 and 15-18-yr-old at session 2. STUDY SAMPLE: Participants were 82 adolescents with unilateral CIs, who are a subset of a larger longitudinal study. Mean age at implantation was 3.4 yr (range: 1.7-5.4), and mean duration of device use was 5.5 yr (range: 3.8-7.5) at session 1 and 13.3 yr (range: 10.9-15) at session 2. DATA COLLECTION AND ANALYSIS: Speech perception tests at sessions 1 and 2 were the Lexical Neighborhood Test (LNT) presented at 70 dB SPL (LNT-70) and Bamford-Kowal-Bench sentences in quiet (BKB-Q) presented at 70 dB SPL. At session 2, the LNT was also administered at 50 dB SPL (LNT-50), and BKB sentences were administered in noise with a +10 dB SNR (BKB-N). CI processor technology type and CI map characteristics (coding strategy, number of electrodes, threshold levels, and comfort levels) were obtained at both sessions. Electrical dynamic range was computed, and descriptive statistics, correlations, and repeated-measures ANOVAs were employed. RESULTS: Participants achieved significantly higher LNT and BKB scores, at 70 dB SPL, at ages 15-18 than at ages 8-9 yr. Forty-two participants had 1-3 electrodes either activated or deactivated in their map between test sessions, and 40 had no change in number of active electrodes (mean change: -0.5; range: -3 to +2). After conversion from arbitrary clinical map units to charge-per-phase in nanocoulombs (nC), no significant difference was found for T levels across time. Average comfort levels (C levels) decreased by 19 nC. Seventy-three participants (89%) upgraded their CI processor technology type. At both sessions, significant correlations were found between electrical dynamic range (EDR) and all speech perception measures except LNT-50 (r range: .31 to .47; p < 0.01). Similarly, significant correlations were also found between C levels and all speech perception measures (r range: .29 to .49; p < 0.01). At session 2, a significant correlation was found between processor technology type and the LNT-50 scores (r = .38; p < 0.01). CONCLUSIONS: Significant improvement in speech scores was observed between elementary grades and high school for children who had used a CI since preschool. On average, T levels (nC) and electrode function remained stable for these long-term pediatric users. Analyses of maps did not allow for the determination of the exact cause of C level reductions, though power limitations in new processor systems and changes in perceived loudness over time are possible. Larger EDRs and higher C levels were associated with better speech scores. Newer speech processor technology was associated with better speech scores at a softer level.

Long-term outcomes of cochlear implantation in early childhood: sample characteristics and data collection methods.

OBJECTIVES: This article describes participants in a follow-up study of a nationwide sample of children who had used a cochlear implant (CI) since preschool. The children were originally tested when they were in early elementary grades, and results were published in a monograph supplement of Ear and Hearing. Recently, many of these children returned for follow-up testing when they were in high school with >10 yrs experience with a CI. This introductory article will (1) discuss the extent to which the sample tested is representative of typical populations and (2) describe how sample characteristics changed over time for the 112 students tested in both elementary grades and high school. DESIGN: Over a 4-yr period, 112 teenagers from across North America, accompanied by a parent, attended a research camp that was similar to one in which they had participated 8 yrs earlier. A battery of auditory, speech, language, and reading tests was administered, and responses to questionnaires and written language samples were obtained and are described in the following articles in this issue. This article summarizes child, family, and educational characteristics that were quantified so that their role in outcome levels achieved could be examined statistically. For example, metrics were devised to reflect the extent to which a student's language improved when sign language was added to spoken language (i.e., sign enhancement) based on test results obtained in elementary grades and in high school. RESULTS: Comparisons of early characteristics of the 112 students who returned for follow-up testing with the 72 who did not return indicated comparable Performance Intelligence Quotients, communication mode ratings, family education/income, and age at implant. However, follow-up participants had better speech perception, speech intelligibility, and language skills at 8 or 9 yrs of age. Seventy-five percent of returning teenagers were fully mainstreamed in high school (compared with 63% in elementary grades). Only 5% of adolescents were in full-time special education. Grade placement of the teenagers was appropriate to their chronologic age. Estimates of sign enhancement, family characteristics, and Performance Intelligence Quotient were consistent over the two test sessions. CONCLUSIONS: A large proportion of the original sample returned for follow-up testing in adolescence, but they were a more selective group than nonreturning subjects, and their scores may overestimate long-term CI outcomes for the general population. On the other hand, CI-HS students who participated in this study received their device >10 yrs ago and did not have some of the advantages available to more recently implanted children, so their results may underestimate those outcomes.

Factors contributing to speech perception scores in long-term pediatric cochlear implant users.

OBJECTIVES: The objectives of this report are to (1) describe the speech perception abilities of long-term pediatric cochlear implant (CI) recipients by comparing scores obtained at elementary school (CI-E, 8 to 9 yrs) with scores obtained at high school (CI-HS, 15 to 18 yrs); (2) evaluate speech perception abilities in demanding listening conditions (i.e., noise and lower intensity levels) at adolescence; and (3) examine the relation of speech perception scores to speech and language development over this longitudinal timeframe. DESIGN: All 112 teenagers were part of a previous nationwide study of 8- and 9-yr-olds (N = 181) who received a CI between 2 and 5 yrs of age. The test battery included (1) the Lexical Neighborhood Test (LNT; hard and easy word lists); (2) the Bamford Kowal Bench sentence test; (3) the Children's Auditory-Visual Enhancement Test; (4) the Test of Auditory Comprehension of Language at CI-E; (5) the Peabody Picture Vocabulary Test at CI-HS; and (6) the McGarr sentences (consonants correct) at CI-E and CI-HS. CI-HS speech perception was measured in both optimal and demanding listening conditions (i.e., background noise and low-intensity level). Speech perception scores were compared based on age at test, lexical difficulty of stimuli, listening environment (optimal and demanding), input mode (visual and auditory-visual), and language age. RESULTS: All group mean scores significantly increased with age across the two test sessions. Scores of adolescents significantly decreased in demanding listening conditions. The effect of lexical difficulty on the LNT scores, as evidenced by the difference in performance between easy versus hard lists, increased with age and decreased for adolescents in challenging listening conditions. Calculated curves for percent correct speech perception scores (LNT and Bamford Kowal Bench) and consonants correct on the McGarr sentences plotted against age-equivalent language scores on the Test of Auditory Comprehension of Language and Peabody Picture Vocabulary Test achieved asymptote at similar ages, around 10 to 11 yrs. CONCLUSIONS: On average, children receiving CIs between 2 and 5 yrs of age exhibited significant improvement on tests of speech perception, lipreading, speech production, and language skills measured between primary grades and adolescence. Evidence suggests that improvement in speech perception scores with age reflects increased spoken language level up to a language age of about 10 yrs. Speech perception performance significantly decreased with softer stimulus intensity level and with introduction of background noise. Upgrades to newer speech processing strategies and greater use of frequency-modulated systems may be beneficial for ameliorating performance under these demanding listening conditions.

Factors influencing speech production in elementary and high school-aged cochlear implant users.

OBJECTIVES: The objectives of this study were to (a) evaluate changes in speech intelligibility in a group of 110 adolescent users of cochlear implants who were first assessed in elementary school (CI-E) and later in high school (CI-HS) and (b) examine factors influencing speech intelligibility performance at the CI-E and CI-HS sessions. DESIGN: Participants were 110 adolescents who participated in an earlier study examining 181 young elementary school-aged children. Primary outcome measures included speech intelligibility under quiet and multispeaker background conditions and consonants correct produced in the sentences. Multiple linear regressions were used to evaluate how participant, family, and performance measures influenced their speech production during adolescence. Performance measures included estimates of speech perception, working memory, sign enhancement, and duration of seven-syllable sentences. Participant and family measures included duration of deafness, performance intelligence quotients, gender, family size, and socioeconomic status. Principal component analyses were used to construct common variables across highly intercorrelated measures. Three sets of multiple linear regressions evaluated the contributions of the variables to the variance associated with adolescent speech intelligibility. RESULTS: Speech intelligibility and consonants correct significantly increased nearly 22% between the two test sessions. Speech intelligibility significantly decreased by approximately 20% in the multispeaker babble condition relative to the quiet condition. Duration of seven-syllable sentences significantly decreased during the two test sessions. Data revealed that 65.8% of the variance in adolescent speech intelligibility was predicted from participant, family, and performance measures observed in elementary school. Forty-nine percent of the variance at adolescence was accounted for by the participant, family, and performance measures observed during the high school test session. Evaluation of variance including participant and family measures at both time periods, in conjunction with the adolescent performance measures, accounted for 49% of the variance in adolescence performance. After contributions from participant and family variables at the elementary and adolescent test sessions were removed, 21% of the variance in adolescent speech intelligibility was due to the performance measures at adolescence. Independent predictors of performance at adolescence included negative effects of sign enhancement and duration of seven-syllable sentences. CONCLUSIONS: Substantial improvements were made in consonant accuracy, sentence duration, and speech intelligibility between elementary and high school test sessions. Reductions in speech intelligibility performance suggest that allophonic variations, distortions, or use of speech sounds in a nonambient language may contribute to the reductions observed in multispeaker background conditions. Although a significant amount of variance in adolescent performance is accounted for by participant and family characteristics, elementary school speech production and an early reliance on speaking and listening independently account for variance in adolescence speech intelligibility. Over and beyond all the contributions made by participant, family and performance measures, greater reliance on oral communication, and shorter sentence durations independently account for variance at adolescence.