Word Learning in Children With Cochlear Implants: Examining Performance Relative to Hearing Peers and Relations With Age at Implantation

Retrieval practice and word learning in children who are hard of hearing

PURPOSE

Many children who are deaf and hard of hearing (DHH) show poorer auditory word-learning skills than children with typical hearing (TH). The goal of this study was to test the effect of retrieval practice on word learning in children who are hard of hearing (HH).

METHOD

Twenty-six TH children and 16 children who are HH completed a speech perception and a vocabulary test, and a rapid word-learning game to learn new words under no retrieval, immediate retrieval, and spaced retrieval conditions.

RESULT

Linear mixed-effect models revealed that learning condition and time predicted 48% of the variance in word recognition, and age predicted 15% of word recall variance. We observed no differences in word recognition and recall between TH children and children who are HH. Children learned and remembered more words in the immediate and spaced retrieval practice conditions than in the no retrieval condition.

CONCLUSION

Retrieval practice is more effective for word learning and retention than passive exposure (no retrieval). Clinical and educational practices for children who are DHH could combine explicit instruction using targeted exposures and retrieval of new words with naturalistic approaches. Future studies should assess retrieval practice in real-life interventions to inform clinical and educational practices.

Word Learning in Deaf Adults Who Use Cochlear Implants: The Role of Talker Variability and Attention to the Mouth

OBJECTIVES

Although cochlear implants (CIs) facilitate spoken language acquisition, many CI listeners experience difficulty learning new words. Studies have shown that highly variable stimulus input and audiovisual cues improve speech perception in CI listeners. However, less is known whether these two factors improve perception in a word learning context. Furthermore, few studies have examined how CI listeners direct their gaze to efficiently capture visual information available on a talker's face. The purpose of this study was two-fold: (1) to examine whether talker variability could improve word learning in CI listeners and (2) to examine how CI listeners direct their gaze while viewing a talker speak.

DESIGN

Eighteen adults with CIs and 10 adults with normal hearing (NH) learned eight novel word-object pairs spoken by a single talker or six different talkers (multiple talkers). The word learning task comprised of nonsense words following the phonotactic rules of English. Learning was probed using a novel talker in a two-alternative forced-choice eye gaze task. Learners' eye movements to the mouth and the target object (accuracy) were tracked over time.

RESULTS

Both groups performed near ceiling during the test phase, regardless of whether they learned from the same talker or different talkers. However, compared to listeners with NH, CI listeners directed their gaze significantly more to the talker's mouth while learning the words.

CONCLUSIONS

Unlike NH listeners who can successfully learn words without focusing on the talker's mouth, CI listeners tended to direct their gaze to the talker's mouth, which may facilitate learning. This finding is consistent with the hypothesis that CI listeners use a visual processing strategy that efficiently captures redundant audiovisual speech cues available at the mouth. Due to ceiling effects, however, it is unclear whether talker variability facilitated word learning for adult CI listeners, an issue that should be addressed in future work using more difficult listening conditions.

Does Lexical Stress Pattern Affect Learning and Producing New Words in Greek for Children With Cochlear Implants?

PURPOSE

Τhe lexical stress pattern (trochaic vs. iambic) may affect various aspects of word learning and word production in children with cochlear implants (CIs). This study aimed to investigate lexical stress effects in word learning by Greek-speaking children with CIs.

METHOD

A word learning paradigm, consisting of a word production and a word identification task, was used. A test list of eight pairs of disyllabic nonwords with identical phonological composition and contrasting lexical stress (eight trochaic and eight iambic), along with their referent pictured objects, was constructed and administered to 22 Greek-speaking children with CIs (ages 4;6-12;3 [years;months]) with normal nonverbal IQ and to 22 age-matched controls with normal hearing (NH) and no other difficulties.

RESULTS

Overall, children with CIs exhibited lower performance than their hearing peers in all word-learning tasks, regardless of lexical stress pattern. Specifically, they identified significantly fewer words and exhibited significantly lower accuracy in word production than those of the controls. In the group with CIs, lexical stress pattern affected their production of words but not their word identification. Children with CIs showed more accurate production of iambic than trochaic words, a fact attributed to better vowel production. Yet, production of stress was less accurate for iambic than for trochaic words. Μoreover, stress assignment of iambic words was highly correlated with speech and language tests in children with CIs.

CONCLUSIONS

Greek children with CIs exhibited lower performance in the word-learning task administered than children with NH did. In addition, the performance of children with CIs indicated a dissociation between the perception and production mechanisms and revealed complex relations between the segmental and prosodic aspects of words. Preliminary findings suggest that stress assignment in iambic words can serve as an indicator of speech and language growth.

The Importance of High-Frequency Bandwidth on Speech and Language Development in Children: A Review of Patricia Stelmachowicz's Contributions to Pediatric Audiology

We review the literature related to Patricia Stelmachowicz's research in pediatric audiology, specifically focusing on the influence of audibility in language development and acquisition of linguistic rules. Pat Stelmachowicz spent her career increasing our awareness and understanding of children with mild to severe hearing loss who use hearing aids. Using a variety of novel experiments and stimuli, Pat and her colleagues produced a robust body of evidence to support the hypothesis that development moderates the role of frequency bandwidth on speech perception, particularly for fricative sounds. The prolific research that came out of Pat's lab had several important implications for clinical practice. First, her work highlighted that children require access to more high-frequency speech information than adults in the detection and identification of fricatives such as /s/ and /z/. These high-frequency speech sounds are important for morphological and phonological development. Consequently, the limited bandwidth of conventional hearing aids may delay the formation of linguistic rules in these two domains for children with hearing loss. Second, it emphasized the importance of not merely applying adult findings to the clinical decision-making process in pediatric amplification. Clinicians should use evidence-based practices to verify and provide maximum audibility for children who use hearing aids to acquire spoken language.

Differences in picture naming between children with cochlear implants and children with typical hearing

Increase in the auditory abilities of children with cochlear implants (CIs) has led to an improvement in naming tasks, although divergent results are still being reported; this strongly suggests that further studies are needed. The study aims to compare the responses in a picture-naming activity between the complete population of children aged 5 to 7 with cochlear implants in Catalonia -Spain- (N = 31), without developmental problems, and a matched sample of 31 children with typical hearing. A picture-naming task was used to assess their lexical naming abilities. The results show that children with CIs provide more non-responses, they produce fewer words correctly, they require a longer reaction time and they commit more picture-naming errors than children with typical hearing. The auditory age does significantly affect the results, but not the type of implant. In spite of the hearing gain achieved with the cochlear implant and the listening experience progressively achieved in distinct contexts, further explicit work on lexical naming in speech-therapy intervention is clearly required.

Sonority-Related Novel Word Learning Ability of Children With Cochlear Implants With Optimal Oral Language Exposure

OBJECTIVES

The present study investigated how children with cochlear implants (CIs), with optimal exposure to oral language, perform on sonority-related novel word learning tasks. By optimal oral language exposure, we refer to bilateral cochlear implantation below the age of 2 years. Sonority is the relative perceptual prominence/loudness of speech sounds of the same length, stress, and pitch. The present study is guided by a previous study that investigated the sonority-related novel word learning ability of a group of children with CIs, in the Greek language, of which the majority were implanted beyond the age of 2 unilaterally.

DESIGN

A case-control study with 15 Dutch-speaking participants in each of the three groups, i.e., children with CIs, normal-hearing children (NHC), and normal-hearing adults, was conducted using a sonority-related novel "CVC" word learning task. All children with CIs are implanted before the age of 2 years with preimplant hearing aids. Thirteen out of the 15 children had bilateral CIs. The CVC words were constructed according to four sonority conditions, where N is nonsonorous and S is a sonorous phoneme: NSN, NSS, SSN, and SSS. Outcome measures were accuracy and reaction times (RTs). In addition, the Peabody picture vocabulary test and the digit span forward test were administered to the children.

RESULTS

There were no statistical differences in accuracy or RTs between the children groups on the overall score and across the different conditions. However, children with CIs, unlike NHC, scored statistically less accurately and with longer RTs relative to normal-hearing adults, on the overall task. Within-group comparisons showed that none of the groups performed statistically differently on any of the conditions. The NHC showed higher receptive vocabulary scores relative to children with CIs. In addition, the group of children with CIs entailed a statistically significantly higher number of children with "weak" short-term memory.

CONCLUSIONS

Children with CIs who have optimal oral language exposure showed age-appropriate sonority-related novel word learning abilities and strategies relative to their NH peers. However, children with CIs continue to show lower receptive vocabulary scores than NHC, despite the equivalent novel word learning ability. This suggests that children with CIs may have difficulties in retaining newly learned words. Future work should look into possible causes of the gap in performance. This would eventually aid in rehabilitation tailored to the needs of the individual.

The Impact of Hearing Experience on Children's Use of Phonological and Semantic Information During Lexical Access

Purpose The purpose of this study was to examine the extent to which phonological competition and semantic priming influence lexical access in school-aged children with cochlear implants (CIs) and children with normal acoustic hearing. Method Participants included children who were 5-10 years of age with either normal hearing (n = 41) or bilateral severe to profound sensorineural hearing loss and used CIs (n = 13). All participants completed a two-alternative forced-choice task while eye gaze to visual images was recorded and quantified during a word recognition task. In this task, the target image was juxtaposed with a competitor image that was either a phonological onset competitor (i.e., shared the same initial consonant-vowel-consonant syllable as the target) or an unrelated distractor. Half of the trials were preceded by an image prime that was semantically related to the target image. Results Children with CIs showed evidence of phonological competition during real-time processing of speech. This effect, however, was less and occurred later in the time course of speech processing than what was observed in children with normal hearing. The presence of a semantically related visual prime reduced the effects of phonological competition in both groups of children but to a greater degree in children with CIs. Conclusions Children with CIs were able to process single words similarly to their counterparts with normal hearing. However, children with CIs appeared to have increased reliance on surrounding semantic information compared to their normal-hearing counterparts.

Rehabilitation of Severe to Profound Sensorineural Hearing Loss in Adults: Audiological Outcomes

The aim of this article is to describe the audiological patterns of 71 adult patients presenting severe to profound sensorineural hearing loss, who were rehabilitated by cochlear implants (CIs) and hearing aids. This is a retrospective study in a university setting, where the clinical records of 71 adult patients were reviewed and processed. Speech intelligibility was evaluated at one aided ear (CI) or at both aided ears (double CI or a combination of CI and hearing aid [HA]). Patients with a bilateral CI or with a bimodal hearing setup (CI and HA) performed better than those with a single CI; data from the phonetic matrices test showed that there was a statistically significant difference among patients aided by a single CI versus binaural setup (double CI or CI + HA). In particular, patients aided by a bilateral CI, or by a CI and HA, showed an improvement in the functional results of the speech tests, compared to patients using a single CI. Binaural hearing (either with a bilateral CI or bimodal) allows an improvement in the functional results at the speech tests, compared to the use of a CI only.

Are French Fries a Vegetable? Lexical Typicality Judgement Differences in Deaf and Hearing Learners

Deaf and hard-of-hearing (DHH) learners are known to have vocabulary knowledge and language outcomes more heterogeneous than their hearing peers, with a greater incidence of difficulties presumably related (both as cause and effect) to documented challenges in academic domains. In particular, there is increasing evidence that differences may exist in the ways that semantic networks are structured and accessed in DHH and hearing learners. Individuals' judgments of word typicality offers a window into their semantic networks, revealing internal relationships in the mental lexicon. In the present study, 90 DHH and hearing college-aged learners provided typicality ratings at two points in time for 120 words common words considered to be central, borderline, or non-members of six categories. DHH and hearing participants differed in terms of their word knowledge, rating consistency, and rating magnitudes. Relative to hearing peers, DHH participants reported not knowing more of the words, but rated all words as being more typical than did hearing participants and rated the typicality of items more consistently over time. Implications of these findings for understanding mental lexicon structure for DHH and hearing learners, interpreting previous research, and constructing stimuli for future research are discussed.

Comparing Word Characteristic Effects on Vocabulary of Children with Cochlear Implants

Many studies have evaluated overall vocabulary knowledge of children who use cochlear implants, but there has been minimal focus on how word form characteristics affect this knowledge. This study evaluates the effects of neighborhood density and phonotactic probability on the expressive vocabulary of 81 children between five and seven years old (n = 27 cochlear implant users, n = 27 children matched for chronological age, and n = 27 children matched for vocabulary size). Children were asked to name pictures associated with words that have common and rare phonotactic probability and high and sparse neighborhood density. Results indicate that children with cochlear implants, similar to both groups of children with typical hearing, tend to know words with common probability/high density or with rare probability/ sparse density. Patterns of word knowledge for children with cochlear implants mirrored younger children matched for vocabulary size rather than age-matched children with typical hearing.