Measures of working memory span and verbal rehearsal speed in deaf children after cochlear implantation

Cross-modal digit span and vocabulary proficiency in deaf or hard-of-hearing children

This study aims to examine the relationship between vocabulary proficiency and short-term memory capacity in deaf or hard-of-hearing (DHH) children. We test the hypothesis that the relationship between vocabulary skills and digit span performance could be strengthened when the digit span task encompasses cross-modal integration processes. A group of DHH children performed two types of auditory digit span tasks. Furthermore, they participated in a standardized vocabulary proficiency test, comprising two subtests: Receptive Vocabulary and Expressive Vocabulary. The verbal digit span served as a significant predictor of Expressive Vocabulary among the DHH children. Simultaneously, the auditory-pointing digit span accounted for a substantial portion of performance variation in both Receptive and Expressive Vocabulary. After considering the impact of the duration of auditory-verbal intervention through regression models, likelihood ratio tests demonstrated that the auditory-pointing digit span persisted as a significant determinant of both receptive and expressive vocabulary skills. A positive influence of the intervention was also confirmed by the present results. This study provides evidence that memory span and the ability to integrate cross-modal information could serve as significant cognitive correlates of vocabulary proficiency in DHH children.

Speech Recognition and Spatial Hearing in Young Adults With Down Syndrome: Relationships With Hearing Thresholds and Auditory Working Memory

OBJECTIVES

Individuals with Down syndrome (DS) have a higher incidence of hearing loss (HL) compared with their peers without developmental disabilities. Little is known about the associations between HL and functional hearing for individuals with DS. This study investigated two aspects of auditory functions, "what" (understanding the content of sound) and "where" (localizing the source of sound), in young adults with DS. Speech reception thresholds in quiet and in the presence of interferers provided insight into speech recognition, that is, the "what" aspect of auditory maturation. Insights into "where" aspect of auditory maturation were gained from evaluating speech reception thresholds in colocated versus separated conditions (quantifying spatial release from masking) as well as right versus left discrimination and sound location identification. Auditory functions in the "where" domain develop during earlier stages of cognitive development in contrast with the later developing "what" functions. We hypothesized that young adults with DS would exhibit stronger "where" than "what" auditory functioning, albeit with the potential impact of HL. Considering the importance of auditory working memory and receptive vocabulary for speech recognition, we hypothesized that better speech recognition in young adults with DS, in quiet and with speech interferers, would be associated with better auditory working memory ability and receptive vocabulary.

DESIGN

Nineteen young adults with DS (aged 19 to 24 years) participated in the study and completed assessments on pure-tone audiometry, right versus left discrimination, sound location identification, and speech recognition in quiet and with speech interferers that were colocated or spatially separated. Results were compared with published data from children and adults without DS and HL, tested using similar protocols and stimuli. Digit Span tests assessed auditory working memory. Receptive vocabulary was examined using the Peabody Picture Vocabulary Test Fifth Edition.

RESULTS

Seven participants (37%) had HL in at least 1 ear; 4 individuals had mild HL, and 3 had moderate HL or worse. Participants with mild or no HL had ≥75% correct at 5° separation on the discrimination task and sound localization root mean square errors (mean ± SD: 8.73° ± 2.63°) within the range of adults in the comparison group. Speech reception thresholds in young adults with DS were higher than all comparison groups. However, spatial release from masking did not differ between young adults with DS and comparison groups. Better (lower) speech reception thresholds were associated with better hearing and better auditory working memory ability. Receptive vocabulary did not predict speech recognition.

CONCLUSIONS

In the absence of HL, young adults with DS exhibited higher accuracy during spatial hearing tasks as compared with speech recognition tasks. Thus, auditory processes associated with the "where" pathways appear to be a relative strength than those associated with "what" pathways in young adults with DS. Further, both HL and auditory working memory impairments contributed to difficulties in speech recognition in the presence of speech interferers. Future larger-sized samples are needed to replicate and extend our findings.

How Hearing Loss and Cochlear Implantation Affect Verbal Working Memory: Evidence From Adolescents

PURPOSE

Verbal working memory is poorer for children with hearing loss than for peers with normal hearing (NH), even with cochlear implantation and early intervention. Poor verbal working memory can affect academic performance, especially in higher grades, making this deficit a significant problem. This study examined the stability of verbal working memory across middle childhood, tested working memory in adolescents with NH or cochlear implants (CIs), explored whether signal enhancement can improve verbal working memory, and tested two hypotheses proposed to explain the poor verbal working memory of children with hearing loss: (a) Diminished auditory experience directly affects executive functions, including working memory; (b) degraded auditory inputs inhibit children's abilities to recover the phonological structure needed for encoding verbal material into storage.

DESIGN

Fourteen-year-olds served as subjects: 55 with NH; 52 with CIs. Immediate serial recall tasks were used to assess working memory. Stimuli consisted of nonverbal, spatial stimuli and four kinds of verbal, acoustic stimuli: nonrhyming and rhyming words, and nonrhyming words with two kinds of signal enhancement: audiovisual and indexical. Analyses examined (a) stability of verbal working memory across middle childhood, (b) differences in verbal and nonverbal working memory, (c) effects of signal enhancement on recall, (d) phonological processing abilities, and (e) source of the diminished verbal working memory in adolescents with cochlear implants.

RESULTS

Verbal working memory remained stable across middle childhood. Adolescents across groups performed similarly for nonverbal stimuli, but those with CIs displayed poorer recall accuracy for verbal stimuli; signal enhancement did not improve recall. Poor phonological sensitivity largely accounted for the group effect.

CONCLUSIONS

The central executive for working memory is not affected by hearing loss or cochlear implantation. Instead, the phonological deficit faced by adolescents with CIs denigrates the representation in storage and augmenting the signal does not help.

Two are better than one: Differences in cortical EEG patterns during auditory and visual verbal working memory processing between Unilateral and Bilateral Cochlear Implanted children

Despite the proven effectiveness of cochlear implant (CI) in the hearing restoration of deaf or hard-of-hearing (DHH) children, to date, extreme variability in verbal working memory (VWM) abilities is observed in both unilateral and bilateral CI user children (CIs). Although clinical experience has long observed deficits in this fundamental executive function in CIs, the cause to date is still unknown. Here, we have set out to investigate differences in brain functioning regarding the impact of monaural and binaural listening in CIs compared with normal hearing (NH) peers during a three-level difficulty n-back task undertaken in two sensory modalities (auditory and visual). The objective of this pioneering study was to identify electroencephalographic (EEG) marker pattern differences in visual and auditory VWM performances in CIs compared to NH peers and possible differences between unilateral cochlear implant (UCI) and bilateral cochlear implant (BCI) users. The main results revealed differences in theta and gamma EEG bands. Compared with hearing controls and BCIs, UCIs showed hypoactivation of theta in the frontal area during the most complex condition of the auditory task and a correlation of the same activation with VWM performance. Hypoactivation in theta was also observed, again for UCIs, in the left hemisphere when compared to BCIs and in the gamma band in UCIs compared to both BCIs and NHs. For the latter two, a correlation was found between left hemispheric gamma oscillation and performance in the audio task. These findings, discussed in the light of recent research, suggest that unilateral CI is deficient in supporting auditory VWM in DHH. At the same time, bilateral CI would allow the DHH child to approach the VWM benchmark for NH children. The present study suggests the possible effectiveness of EEG in supporting, through a targeted approach, the diagnosis and rehabilitation of VWM in DHH children.

Delayed auditory experience results in past tense production difficulties and working memory deficits in children with cochlear implants: A comparison with children with developmental language disorder

Extent evidence has shown that morphosyntax is one of the most challenging linguistic areas for children with atypical early language experiences. Over the last couple of years, comparisons between deaf children with CIs and children with DLD have gained interest - as cases of atypical early language experiences, including, but not restricted to, delayed onset of exposure to language input and language-processing difficulties. Evidence suggests that the morphosyntactic difficulties experienced by deaf children with CIs and children with DLD are very similar in nature. However, the few studies that have directly compared both groups are inconclusive, with deaf children with CIs either performing significantly better or on par with children with DLD. These differences in findings can be attributed, in part at least, to a failure to implement essential methodological controls - even more so given that deaf children with CIs comprise a very diverse population. The goal of the present study was to directly compare the performance of deaf children with CIs to that of children with DLD on a morphosyntactic ability known to be particularly difficult for both groups. Specifically, the present study conducted a detailed examination of the past tense marking abilities of deaf children with CIs and children with DLD while controlling for factors specific to deaf children with CIs, for children's basic cognitive abilities as well as for children's age, sex assigned at birth, and SES. Past tense verbs are particularly relevant as they are used as a marker of developmental language disorder (DLD) in children learning French. Moreover, extent evidence shows that deaf children with CIs and children with DLD have important WM difficulties, but also that there is an association between auditory perception, processing abilities, and working memory (WM) abilities as well as with the acquisition of morphological features, including tense marking. Unfortunately, no study has examined the relation between the accurate production of past tense verbs and WM abilities in children with CIs and children with DLD learning French. Fifteen deaf children with CIs between 5 and 7 years of age were compared to 15 children with DLD and to 15 typically-developing monolingual controls (MON), matched on important variables, using a past tense elicitation task as well as measures of phonological and nonverbal WM abilities. The results confirm that the deaf children with CIs and the children with DLD both performed significantly lower than the MON controls on the past tense elicitation task - suggesting that difficulties with past tense verbs in French might not only be a marker of DLD but, instead, a correlate of atypical language acquisition. Of importance, the present study is the first to show that deaf children with CIs perform significantly lower than children with DLD on a past tense elicitation task - highlighting the importance of using methodological controls. As well, significant correlations were found between the performance of the deaf children with CIs and of the children with DLD on the past tense elicitation task and their phonological and nonverbal WM abilities. Taken together with previous studies conducted in the same populations, this represents another evidence suggesting that early atypical language experiences result in language and WM deficits, including morphosyntactic difficulties.

Exposure to sign language prior and after cochlear implantation increases language and cognitive skills in deaf children

Recent evidence suggests that deaf children with CIs exposed to nonnative sign language from hearing parents can attain age-appropriate vocabularies in both sign and spoken language. It remains to be explored whether deaf children with CIs who are exposed to early nonnative sign language, but only up to implantation, also benefit from this input and whether these benefits also extend to memory abilities, which are strongly linked to language development. The present study examined the impact of deaf children's early short-term exposure to nonnative sign input on their spoken language and their phonological memory abilities. Deaf children who had been exposed to nonnative sign input before and after cochlear implantation were compared to deaf children who never had any exposure to sign input as well as to children with typical hearing. The children were between 5;1 and 7;1 years of age at the time of testing and were matched on age, sex, and socioeconomic status. The results suggest that even short-term exposure to nonnative sign input has positive effects on general language and phonological memory abilities as well as on nonverbal working memory-with total length of exposure to sign input being the best predictor of deaf children's performance on these measures. The present data suggest that even access to early short-term nonnative visual language input is beneficial for the language and phonological memory abilities of deaf children with cochlear implants, suggesting also that parents should not be discouraged from learning and exposing their child to sign language. RESEARCH HIGHLIGHTS: This is the first study to examine the effects of early short-term exposure to nonnative sign input on French-speaking children with cochlear implants' spoken language and memory abilities. Early short-term nonnative exposure to sign input can have positive consequences for the language and phonological memory abilities of deaf children with CIs. Extended exposure to sign input has some additional and important benefits, allowing children to perform on par with children with typical hearing.

Impact of SNR, peripheral auditory sensitivity, and central cognitive profile on the psychometric relation between pupillary response and speech performance in CI users

Despite substantial technical advances and wider clinical use, cochlear implant (CI) users continue to report high and elevated listening effort especially under challenging noisy conditions. Among all the objective measures to quantify listening effort, pupillometry is one of the most widely used and robust physiological measures. Previous studies with normally hearing (NH) and hearing-impaired (HI) listeners have shown that the relation between speech performance in noise and listening effort (as measured by peak pupil dilation) is not linear and exhibits an inverted-U shape. However, it is unclear whether the same psychometric relation exists in CI users, and whether individual differences in auditory sensitivity and central cognitive capacity affect this relation. Therefore, we recruited 17 post-lingually deaf CI adults to perform speech-in-noise tasks from 0 to 20 dB SNR with a 4 dB step size. Simultaneously, their pupillary responses and self-reported subjective effort were recorded. To characterize top-down and bottom-up individual variabilities, a spectro-temporal modulation task and a set of cognitive abilities were measured. Clinical word recognition in quiet and Quality of Life (QoL) were also collected. Results showed that at a group level, an inverted-U shape psychometric curve between task difficulty (SNR) and peak pupil dilation (PPD) was not observed. Individual shape of the psychometric curve was significantly associated with some individual factors: CI users with higher clinical word and speech-in-noise recognition showed a quadratic decrease of PPD over increasing SNRs; CI users with better non-verbal intelligence and lower QoL showed smaller average PPD. To summarize, individual differences in CI users had a significant impact on the psychometric relation between pupillary response and task difficulty, hence affecting the interpretation of pupillary response as listening effort (or engagement) at different task difficulty levels. Future research and clinical applications should further characterize the possible effects of individual factors (such as motivation or engagement) in modulating CI users' occurrence of 'tipping point' on their psychometric functions, and develop an individualized method for reliably quantifying listening effort using pupillometry.

Cingulate cortex facilitates auditory perception under challenging listening conditions

We often exert greater cognitive resources (i.e., listening effort) to understand speech under challenging acoustic conditions. This mechanism can be overwhelmed in those with hearing loss, resulting in cognitive fatigue in adults, and potentially impeding language acquisition in children. However, the neural mechanisms that support listening effort are uncertain. Evidence from human studies suggest that the cingulate cortex is engaged under difficult listening conditions, and may exert top-down modulation of the auditory cortex (AC). Here, we asked whether the gerbil cingulate cortex (Cg) sends anatomical projections to the AC that facilitate perceptual performance. To model challenging listening conditions, we used a sound discrimination task in which stimulus parameters were presented in either 'Easy' or 'Hard' blocks (i.e., long or short stimulus duration, respectively). Gerbils achieved statistically identical psychometric performance in Easy and Hard blocks. Anatomical tracing experiments revealed a strong, descending projection from layer 2/3 of the Cg1 subregion of the cingulate cortex to superficial and deep layers of primary and dorsal AC. To determine whether Cg improves task performance under challenging conditions, we bilaterally infused muscimol to inactivate Cg1, and found that psychometric thresholds were degraded for only Hard blocks. To test whether the Cg-to-AC projection facilitates task performance, we chemogenetically inactivated these inputs and found that performance was only degraded during Hard blocks. Taken together, the results reveal a descending cortical pathway that facilitates perceptual performance during challenging listening conditions.

Significance Statement

Sensory perception often occurs under challenging conditions, such a noisy background or dim environment, yet stimulus sensitivity can remain unaffected. One hypothesis is that cognitive resources are recruited to the task, thereby facilitating perceptual performance. Here, we identify a top-down cortical circuit, from cingulate to auditory cortex in the gerbils, that supports auditory perceptual performance under challenging listening conditions. This pathway is a plausible circuit that supports effortful listening, and may be degraded by hearing loss.

Early cochlear implantation supports narrative skills of children with prelingual single-sided deafness

Prelingual single-sided deafness (SSD) not only affects children's hearing skills, but can also lead to speech-language delays and academic underachievement. Early cochlear implantation leads to improved spatial hearing, but the impact on language development is less studied. In our longitudinal study, we assessed the language skills of young children with SSD and a cochlear implant (CI). In particular, we investigated their narrative skills in comparison to two control groups: children with SSD without a CI, and children with bilateral normal hearing. We found that children with SSD and a CI performed in line with their normal-hearing peers with regard to narrative and verbal short-term memory skills. Children with SSD without a CI had worse narrative (group difference = - 0.67, p = 0.02) and verbal short-term memory (group difference = - 0.68, p = 0.03) scores than the implanted group. Verbal short-term memory scores and grammar scores each correlated positively with narrative scores across all groups. Early grammar scores (at 2-3 years of age) could partially predict later narrative scores (at 4-6 years of age). These results show that young children with prelingual SSD can benefit from early cochlear implantation to achieve age-appropriate language skills. They support the provision of a CI to children with prelingual SSD.

Neurocognitive function in children with cochlear implants and hearing aids: a systematic review

Purpose

To systematically review the existing literature that examines the relationship between cognition, hearing, and language in children using cochlear implants and hearing aids.

Method

The review has been registered in Prospero (Registration: CRD 42020203974). The review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis and examined the scientific literature in VHL, MEDLINE, CINAHL, Scopus, WOS, and Embase. It included original observational studies in children using hearing aids and/or cochlear implants who underwent cognitive and auditory and/or language tests. Data were extracted from the studies and their level of evidence was graded with the Oxford Center for Evidence-Based Medicine: Levels of Evidence. Meta-analysis could not be performed due to data heterogeneity. Outcomes are described in narrative and tables synthesis.

Results

The systematic search and subsequent full-text evaluation identified 21 studies, conducted in 10 different countries. Altogether, their samples comprised 1,098 individuals, aged 0.16-12.6 years. The studies assessed the following cognitive domains: memory, nonverbal cognition, reasoning, attention, executive functions, language, perceptual-motor function, visuoconstructive ability, processing speed, and phonological processing/phonological memory. Children with hearing loss using cochlear implants and hearing aids scored significantly lower in many cognitive functions than normal hearing (NH) children. Neurocognitive functions were correlated with hearing and language outcomes.

Conclusion

Many cognitive tools were used to assess cognitive function in children with hearing devices. Results suggest that children with cochlear implants and hearing aids have cognitive deficits; these outcomes are mainly correlated with vocabulary. This study highlights the need to understand children's cognitive function and increase the knowledge of the relationship between cognition, language, and hearing in children using cochlear implants and hearing aids.

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.

Verbal Fluency in Prelingually Deaf, Early Implanted Children and Adolescents With Cochlear Implants

PURPOSE

Verbal fluency tasks assess the ability to quickly and efficiently retrieve words from the mental lexicon by requiring subjects to rapidly generate words within a phonological or semantic category. This study investigated differences between cochlear implant users and normal-hearing peers in the clustering and time course of word retrieval during phonological and semantic verbal fluency tasks.

METHOD

Twenty-eight children and adolescents (aged 9-17 years) with cochlear implants and 33 normal-hearing peers completed measures of verbal fluency, nonverbal intelligence, speech perception, and verbal short-term/working memory. Phonological and semantic verbal fluency tests were scored for total words generated, words generated in each 10-s interval of the 1-min task, latency to first word generated, number of word clusters, average cluster size, and number of word/cluster switches.

RESULTS

Children and adolescents with cochlear implants generated fewer words than normal-hearing peers throughout the entire 60-s time interval of the phonological and semantic fluency tasks. Cochlear implant users also had slower start latency times and produced fewer clusters and switches than normal-hearing peers during the phonological fluency task. Speech perception and verbal working memory scores were more strongly associated with verbal fluency scores in children and adolescents with cochlear implants than in normal-hearing peers.

CONCLUSIONS

Cochlear implant users show poorer phonological and semantic verbal fluency than normal-hearing peers, and their verbal fluency is significantly associated with speech perception and verbal working memory. These findings suggest deficits in fluent retrieval of phonological and semantic information from long-term lexical memory in cochlear implant users.

Neuropsychological Functions and Audiological Findings in Elderly Cochlear Implant Users: The Role of Attention in Postoperative Performance

Objectives: The present study aimed to investigate in a group of elderly CI users working memory and attention, conventionally considered as predictors of better CI performance and to try to disentangle the effects of these cognitive domains on speech perception, finding potential markers of cognitive decline related to audiometric findings. Methods Thirty postlingually deafened CI users aged >60 underwent an audiological evaluation followed by a cognitive assessment of attention and verbal working memory. A correlation analysis was performed to evaluate the associations between cognitive variables while a simple regression investigated the relationships between cognitive and audiological variables. Comparative analysis was performed to compare variables on the basis of subjects’ attention performance. Results: Attention was found to play a significant role in sound field and speech perception. Univariate analysis found a significant difference between poor and high attention performers, while regression analysis showed that attention significantly predicted recognition of words presented at Signal/Noise +10. Further, the high attention performers showed significantly higher scores than low attentional performers for all working memory tasks. Conclusion: Overall findings confirmed that a better cognitive performance may positively contribute to better speech perception outcomes, especially in complex listening situations. WM may play a crucial role in storage and processing of auditory-verbal stimuli and a robust attention may lead to better performance for speech perception in noise. Implementation of cognitive training in auditory rehabilitation of CI users should be investigated in order to improve cognitive and audiological performance in elderly CI users.

Association of Aging and Cognition With Complex Speech Understanding in Cochlear-Implanted Adults: Use of a Modified National Institutes of Health (NIH) Toolbox Cognitive Assessment

Importance

The association between cognitive function and outcomes in cochlear implant (CI) users is not completely understood, partly because some cognitive tests are confounded by auditory status. It is important to determine appropriate cognitive tests to use in a cohort of CI recipients.

Objective

To provide proof-of-concept for using an adapted version of the National Institutes of Health (NIH) Toolbox Cognition Battery in a cohort of patients with CIs and to explore how hearing in noise with a CI is affected by cognitive status using the adapted test.

Design, Setting, and Participants

In this prognostic study, participants listened to sentences presented in a speech-shaped background noise. Cognitive tests consisted of 7 subtests of the NIH Toolbox Cognition Battery that were adapted for hearing impaired individuals by including written instructions and visual stimuli. Participants were prospectively recruited from and evaluated at a tertiary medical center. All participants had at least 6 months' experience with their CI.

Main Outcomes and Measures

The main outcomes were performance on the adapted cognitive test and a speech recognition in noise task.

Results

Participants were 20 adult perilingually or postlingually deafened CI users (50% male participants; median [range] age, 66 [26-80] years old). Performance on a sentence recognition in noise task was negatively associated with the chronological age of the listener (R2 = 0.29; β = 0.16; standard error, SE = 0.06; t = 2.63; 95% confidence interval, 0.03-0.27). Testing using the adapted version of the NIH Toolbox Cognition Battery revealed that a test of processing speed was also associated with performance, using a standardized score that accounted for contributions of other demographic factors (R2 = 0.28; 95% confidence interval, -0.42 to -0.05).

Conclusions and Relevance

In this prognostic study, older CI users showed poorer performance on a sentence-in-noise test compared with younger users. This poorer performance was correlated with a cognitive deficit in processing speed when cognitive function was assessed using a test battery adapted for participants with hearing loss. These results provide initial proof-of-concept results for using a standardized and adapted cognitive test battery in CI recipients.

The 100 Most-Cited Manuscripts in Hearing Implants: A Bibliometrics Analysis

The aim of the study was to characterise the most frequently cited articles on the topic of hearing implants. A systematic search was carried out using the Thomson Reuters Web of Science Core Collection database. Eligibility criteria restricted the results to primary studies and reviews published from 1970 to 2022 in English dealing primarily with hearing implants. Data including the authors, year of publication, journal, country of origin, number of citations and average number of citations per year were extracted, as well as the impact factors and five-year impact factor of journals publishing the articles. The top 100 papers were published across 23 journals and were cited 23,139 times. The most-cited and influential article describes the first use of the continuous interleaved sampling (CIS) strategy utilised in all modern cochlear implants. More than half of the studies on the list were produced by authors from the United States, and the Ear and Hearing journal had both the greatest number of articles and the greatest number of total citations. To conclude, this research serves as a guide to the most influential articles on the topic of hearing implants, although bibliometric analyses mainly focus on citations. The most-cited article was an influential description of CIS.

The effect of sentence length on question comprehension in children with cochlear implants

OBJECTIVES

The present study investigated the comprehension of subject and object who and which questions in children with cochlear implants (CI).

METHODS

Growth Curve Analysis (GCA) was used to compare eye gaze fixations and gaze patterns to the appropriate subject or object nouns within a four-picture array between 16 children with CI and 31 children with typical hearing (aged 7;0-12;0) on wh-questions with and without added adjectives to increase length. Offline accuracy was also compared.

RESULTS

Findings indicated children with typical hearing exhibited more fixations to the target noun across all conditions, supporting higher comprehension accuracy. Both groups of children demonstrated more fixations to the target noun in object questions and questions without added length. Patterns of eye movement were significantly different between groups, suggesting different patterns of eye gaze across the array before fixation on the target noun. Children with CI exhibited fewer fixations, slower speed to fixation, and differences in gaze patterns that may imply the presence of processing limitations. Error analyses also suggested that children with CI frequently fixated on a picture similar to the target noun.

CONCLUSIONS

Results indicate children with CI comprehend questions more slowly than their hearing peers, which may be related to limitations in working memory.

Speaking Rate, Immediate Memory, and Grammatical Processing in Prelingual Cochlear Implant Recipients

PURPOSE

This study examined the extent to which prelingual cochlear implant (CI) users show a slowed speaking rate compared with typical-hearing (TH) talkers when repeating various speech stimuli and whether the slowed speech of CI users relates to their immediate verbal memory.

METHOD

Participants included 10 prelingually deaf teenagers who received CIs before the age of 5 years and 10 age-matched TH teenagers. Participants repeated nonword syllable strings, word strings, and center-embedded sentences, with conditions balanced for syllable length and metrical structure. Participants' digit span forward and backward scores were collected to measure immediate verbal memory. Speaking rate data were analyzed using a mixed-design, repeated-measures analysis of variance, and the relationships between speaking rate and digit spans were evaluated by Pearson correlation.

RESULTS

Participants with CIs spoke more slowly than their TH peers during the sentence repetition task but not in the nonword string and word string repetition tasks. For the CI group, significant correlations emerged between speaking rate and digit span scores (both forward and backward) for the sentence repetition task but not for the nonword string or word string repetition task. For the TH group, no significant correlations were found.

CONCLUSIONS

The findings indicate a relation between slowed speech production, reduced immediate verbal memory, and diminished language capabilities of prelingual CI users, particularly for syntactic processing. These results support theories claiming that immediate memory, including components of a central executive, influences the speaking rate of these talkers. Implications for therapies designed to increase speech fluency in CI recipients are discussed.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21644795.

Music and Speech Perception in Prelingually Deafened Young Listeners With Cochlear Implants: A Preliminary Study Using Sung Speech

PURPOSE

In the context of music and speech perception, this study aimed to assess the effect of variation in one of two auditory attributes-pitch contour and timbre-on the perception of the other in prelingually deafened young cochlear implant (CI) users, and the relationship between pitch contour perception and two cognitive functions of interest.

METHOD

Nine prelingually deafened CI users, aged 8.75-22.17 years, completed a melodic contour identification (MCI) task using stimuli of piano notes or sung speech with a fixed timbre (same word for each note) or a mixed timbre (different words for each note), a speech perception task identifying matrix-styled sentences naturally intonated or sung with a fixed pitch (same pitch for each word) or a mixed pitch (different pitches for each word), a forward digit span test indexing auditory short-term memory (STM), and the matrices section of the Kaufman Brief Intelligence Test-Second Edition indexing nonverbal IQ.

RESULTS

MCI was significantly poorer for the mixed timbre condition. Speech perception was significantly poorer for the fixed and mixed pitch conditions than for the naturally intonated condition. Auditory STM positively correlated with MCI at 2- and 3-semitone note spacings. Relative to their normal-hearing peers from a related study using the same stimuli and tasks, the CI participants showed comparable MCI at 2- or 3-semitone note spacing, and a comparable level of significant decrement in speech perception across three pitch contour conditions.

CONCLUSION

Findings suggest that prelingually deafened CI users show similar trends of normal-hearing peers for the effect of variation in pitch contour or timbre on the perception of the other, and that cognitive functions may underlie these outcomes to some extent, at least for the perception of pitch contour.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.21217937.

Gamma-Band Modulation in Parietal Area as the Electroencephalographic Signature for Performance in Auditory-Verbal Working Memory: An Exploratory Pilot Study in Hearing and Unilateral Cochlear Implant Children

This pilot study investigates the neurophysiological patterns of visual and auditory verbal working memory (VWM) in unilateral cochlear implant users (UCIs). We compared the task-related electroencephalogram (EEG) power spectral density of 7- to 13-year-old UCIs (n = 7) with a hearing control group (HC, n = 10) during the execution of a three-level n-back task with auditory and visual verbal (letters) stimuli. Performances improved as memory load decreased regardless of sensory modality (SM) and group factors. Theta EEG activation over the frontal area was proportionally influenced by task level; the left hemisphere (LH) showed greater activation in the gamma band, suggesting lateralization of VWM function regardless of SM. However, HCs showed stronger activation patterns in the LH than UCIs regardless of SM and in the parietal area (PA) during the most challenging audio condition. Linear regressions for gamma activation in the PA suggest the presence of a pattern-supporting auditory VWM only in HCs. Our findings seem to recognize gamma activation in the PA as the signature of effective auditory VWM. These results, although preliminary, highlight this EEG pattern as a possible cause of the variability found in VWM outcomes in deaf children, opening up new possibilities for interdisciplinary research and rehabilitation intervention.

The relationships between language, working memory and rapid naming in children with mild to moderate hearing loss

OBJECTIVE

Hearing loss is associated with reduced quality and quantity of auditory input, and difficulty in cognitive and language skills. This study aimed to investigate the relationship between language, working memory, and rapid naming skills in children with mild to moderate sensorineural hearing loss (MMHL).

METHODS

Twenty children with MMHL with the same auditory experience and demographical conditions using bilateral hearing aids were included. Verbal memory subscale of the Working Memory Scale (WMS), consisting of verbal short-term memory (V-STM) and verbal working memory (V-WM) subtests, was administered to all participants. They also completed rapid automatized naming tasks and standardized language measures.

RESULTS

The language score showed a moderate and significant correlation with verbal memory (VM) score (p = 0.03, r = 0.48) and a moderate and negative correlation with rapid automatized naming (RAN) duration (p = 0.06, r = -0.61). The VM score showed a moderate and significant negative correlation with RAN duration (p = 0.01, r = -0.67). The language level has a strong and significant positive correlation with V-STM (p = 0.007, r = 0.60), V-WM (p = 0.009, r = 0.58), and VM level (p = 0.003, r = 0.65). VM subtests levels have a strong and significant positive correlation with each other (p = 0.017, r = 0.53). RAN level has a strong and significant negative correlation with VM (p = 0.001, r = -0.70), V-WM (p = 0.001, r = -0.76), V-STM (p = 0.001, r = -0.69), and language level (p = 0.001, r = -0.77).

CONCLUSION

The results suggest that the language, verbal working memory, and rapid naming skills of children with MMHL are closely related. It is recommended that the relationship between verbal short-term memory, verbal working memory, rapid naming skills, and language skills should be considered in therapeutic and educational settings. To the best of our knowledge, this is the first study to examine the relationships between verbal-short-term -working memory, duration of rapid automatized naming, and language skills in children with MMHL.

Auditory processing remains sensitive to environmental experience during adolescence in a rodent model

Elevated neural plasticity during development contributes to dramatic improvements in perceptual, motor, and cognitive skills. However, malleable neural circuits are vulnerable to environmental influences that may disrupt behavioral maturation. While these risks are well-established prior to sexual maturity (i.e., critical periods), the degree of neural vulnerability during adolescence remains uncertain. Here, we induce transient hearing loss (HL) spanning adolescence in gerbils, and ask whether behavioral and neural maturation are disrupted. We find that adolescent HL causes a significant perceptual deficit that can be attributed to degraded auditory cortex processing, as assessed with wireless single neuron recordings and within-session population-level analyses. Finally, auditory cortex brain slices from adolescent HL animals reveal synaptic deficits that are distinct from those typically observed after critical period deprivation. Taken together, these results show that diminished adolescent sensory experience can cause long-lasting behavioral deficits that originate, in part, from a dysfunctional cortical circuit.

Amount of Hearing Aid Use Impacts Neural Oscillatory Dynamics Underlying Verbal Working Memory Processing for Children With Hearing Loss

OBJECTIVES

Children with hearing loss (CHL) may exhibit spoken language delays and may also experience deficits in other cognitive domains including working memory. Consistent hearing aid use (i.e., more than 10 hours per day) ameliorates these language delays; however, the impact of hearing aid intervention on the neural dynamics serving working memory remains unknown. The objective of this study was to examine the association between the amount of hearing aid use and neural oscillatory activity during verbal working memory processing in children with mild-to-severe hearing loss.

DESIGN

Twenty-three CHL between 8 and 15 years-old performed a letter-based Sternberg working memory task during magnetoencephalography (MEG). Guardians also completed a questionnaire describing the participants' daily hearing aid use. Each participant's MEG data was coregistered to their structural MRI, epoched, and transformed into the time-frequency domain using complex demodulation. Significant oscillatory responses corresponding to working memory encoding and maintenance were independently imaged using beamforming. Finally, these whole-brain source images were correlated with the total number of hours of weekly hearing aid use, controlling for degree of hearing loss.

RESULTS

During the encoding period, hearing aid use negatively correlated with alpha-beta oscillatory activity in the bilateral occipital cortices and right precentral gyrus. In the occipital cortices, this relationship suggested that with greater hearing aid use, there was a larger suppression of occipital activity (i.e., more negative relative to baseline). In the precentral gyrus, greater hearing aid use was related to less synchronous activity (i.e., less positive relative to baseline). During the maintenance period, hearing aid use significantly correlated with alpha activity in the right prefrontal cortex, such that with greater hearing aid use, there was less right prefrontal maintenance-related activity (i.e., less positive relative to baseline).

CONCLUSIONS

This study is the first to investigate the impact of hearing aid use on the neural dynamics that underlie working memory function. These data show robust relationships between the amount of hearing aid use and phase-specific neural patterns during working memory encoding and maintenance after controlling for degree of hearing loss. Furthermore, our data demonstrate that wearing hearing aids for more than ~8.5 hours/day may serve to normalize these neural patterns. This study also demonstrates the potential for neuroimaging to help determine the locus of variability in outcomes in CHL.

Executive Function Training for Deaf Children: Impact of a Music Intervention

Several studies have reported poor executive function (EF) development in deaf children with subsequent impacts on their social and academic attainment. This paper describes the results of a music-based EF intervention designed for deaf children and carried out in two sets of primary schools. This is the first classroom-based EF training study with deaf children, and it also incorporates a replication phase. The intervention was a within-subject crossover design, with 29 deaf children aged 7-11 years who participated in both an EF and an art class control activity, each lasting 10 hours over 5 weeks. Non-verbal EF skills were assessed at pre-test, the crossover point, and post-test. Findings indicated that the EF intervention led to an improvement in participants' working memory and inhibitory skills in comparison with their performance on the same tasks after the control activity. The findings were not uniform for all EFs targeted nor for all cognitive ability levels in the sample. We discuss the implications of our findings for deaf children with different ability levels and for how EF interventions can be further improved.

Variables influencing executive functioning in preschool hearing-impaired children implanted within 24 months of age: an observational cohort study

PURPOSE

Executive Functions (EFs) are fundamental to every aspect of life. The present study was implemented to evaluate factors influencing their development in a group of preschools orally educated profoundly deaf children of hearing parents, who received CI within 2 years of age.

METHODS

Twenty-five preschool CI children were tested using the Battery for Assessment of Executive Functions (BAFE) to assess their flexibility, inhibition, and non-verbal visuo-spatial working memory skills. The percentage of children performing in normal range was reported for each of the EF subtests. Mann-Whitney and Kruskal-Wallis were performed to assess differences between gender, listening mode, and degree of parents' education subgroups. The Spearman Rank Correlation Coefficient was calculated to investigate the relationship between EF scores of audiological and linguistic variables.

RESULTS

Percentages ranging from 76 to 92% of the children reached adequate EF scores at BAFE. Significant relations (p < 0.05) were found between EFs and early intervention, listening, and linguistic skills. Furthermore, CI children from families with higher education level performed better at the response shifting, inhibitory control, and attention flexibility tasks. Economic income correlated significantly with flexibility and inhibitory skills. Females performed better than males only in the attention flexibility task.

CONCLUSIONS

The present study is one of the first to focus attention on the development of EFs in preschool CI children, providing an initial understanding of the characteristics of EFs at the age when these skills emerge. Clinical practice must pay increasing attention to these aspects which are becoming the new emerging challenge of rehabilitation programs.

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.

Links of Prosodic Stress Perception and Musical Activities to Language Skills of Children With Cochlear Implants and Normal Hearing

OBJECTIVES

A major issue in the rehabilitation of children with cochlear implants (CIs) is unexplained variance in their language skills, where many of them lag behind children with normal hearing (NH). Here, we assess links between generative language skills and the perception of prosodic stress, and with musical and parental activities in children with CIs and NH. Understanding these links is expected to guide future research and toward supporting language development in children with a CI.

DESIGN

Twenty-one unilaterally and early-implanted children and 31 children with NH, aged 5 to 13, were classified as musically active or nonactive by a questionnaire recording regularity of musical activities, in particular singing, and reading and other activities shared with parents. Perception of word and sentence stress, performance in word finding, verbal intelligence (Wechsler Intelligence Scale for Children (WISC) vocabulary), and phonological awareness (production of rhymes) were measured in all children. Comparisons between children with a CI and NH were made against a subset of 21 of the children with NH who were matched to children with CIs by age, gender, socioeconomic background, and musical activity. Regression analyses, run separately for children with CIs and NH, assessed how much variance in each language task was shared with each of prosodic perception, the child's own music activity, and activities with parents, including singing and reading. All statistical analyses were conducted both with and without control for age and maternal education.

RESULTS

Musically active children with CIs performed similarly to NH controls in all language tasks, while those who were not musically active performed more poorly. Only musically nonactive children with CIs made more phonological and semantic errors in word finding than NH controls, and word finding correlated with other language skills. Regression analysis results for word finding and VIQ were similar for children with CIs and NH. These language skills shared considerable variance with the perception of prosodic stress and musical activities. When age and maternal education were controlled for, strong links remained between perception of prosodic stress and VIQ (shared variance: CI, 32%/NH, 16%) and between musical activities and word finding (shared variance: CI, 53%/NH, 20%). Links were always stronger for children with CIs, for whom better phonological awareness was also linked to improved stress perception and more musical activity, and parental activities altogether shared significantly variance with word finding and VIQ.

CONCLUSIONS

For children with CIs and NH, better perception of prosodic stress and musical activities with singing are associated with improved generative language skills. In addition, for children with CIs, parental singing has a stronger positive association to word finding and VIQ than parental reading. These results cannot address causality, but they suggest that good perception of prosodic stress, musical activities involving singing, and parental singing and reading may all be beneficial for word finding and other generative language skills in implanted children.

The impact of mild-to-severe hearing loss on the neural dynamics serving verbal working memory processing in children

Children with hearing loss (CHL) exhibit delays in language function relative to children with normal hearing (CNH). However, evidence on whether these delays extend into other cognitive domains such as working memory is mixed, with some studies showing decrements in CHL and others showing CHL performing at the level of CNH. Despite the growing literature investigating the impact of hearing loss on cognitive and language development, studies of the neural dynamics that underlie these cognitive processes are notably absent. This study sought to identify the oscillatory neural responses serving verbal working memory processing in CHL compared to CNH. To this end, participants with and without hearing loss performed a verbal working memory task during magnetoencephalography. Neural oscillatory responses associated with working memory encoding and maintenance were imaged separately, and these responses were statistically evaluated between CHL and CNH. While CHL performed as well on the task as CNH, CHL exhibited significantly elevated alpha-beta activity in the right frontal and precentral cortices during encoding relative to CNH. In contrast, CHL showed elevated alpha maintenance-related activity in the right precentral and parieto-occipital cortices. Crucially, right superior frontal encoding activity and right parieto-occipital maintenance activity correlated with language ability across groups. These data suggest that CHL may utilize compensatory right-hemispheric activity to achieve verbal working memory function at the level of CNH. Neural behavior in these regions may impact language function during crucial developmental ages.

The development of phonological memory and language: A multiple groups approach

Pierce et al. (2017) have proposed that variations in the timing, quality and quantity of language input during the earliest stages of development are related to variations in the development of phonological working memory and, in turn, to later language learning outcomes. To examine this hypothesis, three groups of children who are at-risk for language learning were examined: children with cochlear implants (CI), children with developmental language disorder (DLD), and internationally-adopted (IA) children, Comparison groups of typically-developing monolingual (MON) children and second language (L2) learners were also included. All groups were acquiring French as a first or second language and were matched on age, gender, and socioeconomic status, as well as other group-specific factors; they were between 5;0-7;3 years of age at time of testing. The CI and DLD groups scored significantly more poorly on the memory measures than the other groups; while the IA and L2 groups did not differ from one another. While the IA group performed more poorly than the MON group, there was no difference between the L2 and MON groups. We also found differential developmental relationships between phonological memory and language among the groups of interest in comparison to the typically-developing MON and L2 groups supporting the hypothesis that language experiences early in life are consequential for language development because of their effects on the development of phonological memory.

Cross-modal plasticity and central deficiencies: the case of deafness and the use of cochlear implants

The primary objective of this chapter is to describe the consequences of central deficiencies on the neurodevelopment of children. We approach this topic from the standpoint of congenital deafness. Thus we first present the current state of knowledge on cortical reorganization following congenital deafness. The allocation of auditory cortices to other sensory systems can enhance sensory processing and therefore the cognitive functions related to them. Second, we explore the linguistic development of deaf children. Given that the English written system is speech-based, its acquisition is complex and atypical for deaf children, usually leading to poorer achievements. Next, we explore the impact of a neural prosthesis named the cochlear implant on the neurocognitive and linguistic development of deaf children. In some cases, it allows the individuals to, at least partially, regain access to the lost sense. We also comment on the specific needs of the deaf population when it comes to neuropsychological assessment. Finally, we touch on the specific context of deaf children born of deaf parents, and therefore naturally exposed to sign language as the only means of communication.

The Limits of "Communication Mode" as a Construct

Questions about communication mode (a.k.a. "communication options" or "communication opportunities") remain among the most controversial issues in the many fields that are concerned with the development and well-being of children (and adults) who are d/Deaf or hard of hearing. In this manuscript, we argue that a large part of the reason that this debate persists is due to limitations of the construct itself. We focus on what we term "the crucial question": namely, what kind of experience with linguistic input during infancy and toddlerhood is most likely to result in mastery of at least one language (spoken or signed) by school entry. We argue that the construct of communication mode-as currently construed-actively prevents the discovery of compelling answers to that question. To substantiate our argument, we present a review of a relevant subset of the recent empirical literature and document the prevalence of our concerns. We conclude by articulating the desiderata of an alternative construct that, if appropriately measured, would have the potential to yield answers to what we identify as "the crucial question."

Global Regulatory Review Needed for Cochlear Implants: A Call for FDA Leadership

INTRODUCTION

Using the United States Food and Drug Administration (FDA) as example, we argue that regulatory agencies worldwide should review their guidance on cochlear implants (CIs).

METHODS

This is a position paper, thus the methods are strictly argumentation. Here we give the motivation for our recommendation. The FDA's original approval of implantation in prelingually deaf children was granted without full benefit of information on language acquisition, on childcaregiver communication, and on the lived experience of being deaf. The CI clinical trials, accordingly, did not address risks of linguistic deprivation, especially when the caregiver's communication is not fully accessible to the prelingually deaf child. Wide variability in the effectiveness of CIs since initial and updated approval has been indicated but has not led to new guidance. Children need to be exposed frequently and regularly to accessible natural language while their brains are still plastic enough to become fluent in any language. For the youngest infants, who are not yet producing anything that could be called language although they might be producing salient social signals (Goldstein et al. Child Dev 80:636-644, 2009), good comprehension of communication from caregiver to infant is critical to the development of language. Sign languages are accessible natural languages that, because they are visual, allow full immersion for deaf infants, and they supply the necessary support for this comprehension. The main language contributor to health outcomes is this combination of natural visual language and comprehension in communication. Accordingly, in order to prevent possible language deprivation, all prelingually deaf children should be exposed to both sign and spoken languages when their auditory status is detected, with sign language being critical during infancy and early childhood. Additionally, all caregivers should be given support to learn a sign language if it is new to them so that they can comprehend their deaf children's language expressions fully. However, both languages should be made accessible in their own right, not combined in a simultaneous or total communication approach since speaking one language and signing the other at the same time is problematic.

RESULTS

Again, because this is a position paper, our results are our recommendations. We call for the FDA (and similar agencies in other countries) to review its approval of cochlear implantation in prelingually deaf children who are within the sensitive period for language acquisition. In the meantime, the FDA should require manufacturers to add a highlighted warning to the effect that results with CI vary widely and CIs should not be relied upon to provide adequate auditory input for complete language development in all deaf children. Recent best information on users' experience with CIs (including abandonment) should be clearly provided so that informed decisions can be made. The FDA should require manufacturers' guidance and information materials to include encouragement to parents of deaf children to offer auditory input of a spoken language and visual input of a sign language and to have their child followed closely from birth by developmental specialists in language and cognition. In this way parents can align with providers to prioritize cognitive development and language access in both audio-vocal and visuo-gestural modalities.

DISCUSSION

The arguments and recommendations in this paper are discussed at length as they come up.

Rhythmic Abilities of Children With Hearing Loss

OBJECTIVES

Children with hearing loss (HL), in spite of early cochlear implantation, often struggle considerably with language acquisition. Previous research has shown a benefit of rhythmic training on linguistic skills in children with HL, suggesting that improving rhythmic capacities could help attenuating language difficulties. However, little is known about general rhythmic skills of children with HL and how they relate to speech perception. The aim of this study is twofold: (1) to assess the abilities of children with HL in different rhythmic sensorimotor synchronization tasks compared to a normal-hearing control group and (2) to investigate a possible relation between sensorimotor synchronization abilities and speech perception abilities in children with HL.

DESIGN

A battery of sensorimotor synchronization tests with stimuli of varying acoustic and temporal complexity was used: a metronome, different musical excerpts, and complex rhythmic patterns. Synchronization abilities were assessed in 32 children (aged from 5 to 10 years) with a severe to profound HL mainly fitted with one or two cochlear implants (n = 28) or with hearing aids (n = 4). Working memory and sentence repetition abilities were also assessed. Performance was compared to an age-matched control group of 24 children with normal hearing. The comparison took into account variability in working memory capacities. For children with HL only, we computed linear regressions on speech, sensorimotor synchronization, and working memory abilities, including device-related variables such as onset of device use, type of device, and duration of use.

RESULTS

Compared to the normal-hearing group, children with HL performed poorly in all sensorimotor synchronization tasks, but the effect size was greater for complex as compared to simple stimuli. Group differences in working memory did not explain this result. Linear regression analysis revealed that working memory, synchronization to complex rhythms performances, age, and duration of device use predicted the number of correct syllables produced in a sentence repetition task.

CONCLUSION

Despite early cochlear implantation or hearing aid use, hearing impairment affects the quality of temporal processing of acoustic stimuli in congenitally deaf children. This deficit seems to be more severe with stimuli of increasing rhythmic complexity highlighting a difficulty in structuring sounds according to a temporal hierarchy.

Discourse Prosody in Children's Rhyme Speech Produced by Prelingually Deaf Mandarin-Speaking Children With Cochlear Implants

Purpose This study aimed to obtain a comprehensive understanding about how Mandarin-speaking children with cochlear implants (CIs) performed speech prosody in a connected discourse and to what extent their prosodic scenario differed from those normal-hearing (NH) peers. Method Fifteen prelingually deaf Mandarin-speaking children with unilateral multichannel CIs were chosen and 15 age-matched NH controls were recruited. Speech samples were spontaneously elicited by children's rhyme speech genre and subject to phonetic annotation. Acoustic analysis was conducted on all speech samples, mainly focusing on the measurements of duration and fundamental frequency (F0). Tempo measures included temporal fluency, syllable-lengthening, and rhythm metrics, whereas melodic measures included both local and global F0 variations under different prosodic domains. Results The CI children generally achieved compatible temporal performance with the NH children in spontaneous discourse, except that they were somewhat arbitrary when operationalizing lengthening strategy and pausing strategy at different prosodic boundaries. With regard to melodic performance, CI children may not sufficiently modulate local phonetic nuances of F0 variation, and meanwhile, they performed atypically in the global F0 declination pattern and overall F0 resetting pattern, failing to signal the specific structure of children's rhyme discourse. Early age at implantation and longer CI experience did not play a significant role in the temporal performance of the CI children but did facilitate their articulation of dynamic pitch variation in the spontaneous discourse to some extent. Conclusion CI children did exhibit atypical prosodic patterns in discourse context, especially the overall mapping between the prosodic manifestation and the discourse structure.

Interactions Between Item Set and Vocoding in Serial Recall

OBJECTIVES

Serial recall of digits is frequently used to measure short-term memory span in various listening conditions. However, the use of digits may mask the effect of low quality auditory input. Digits have high frequency and are phonologically distinct relative to one another, so they should be easy to identify even with low quality auditory input. In contrast, larger item sets reduce listener ability to strategically constrain their expectations, which should reduce identification accuracy and increase the time and/or cognitive resources needed for identification when auditory quality is low. This diminished accuracy and increased cognitive load should interfere with memory for sequences of items drawn from large sets. The goal of this work was to determine whether this predicted interaction between auditory quality and stimulus set in short-term memory exists, and if so, whether this interaction is associated with processing speed, vocabulary, or attention.

DESIGN

We compared immediate serial recall within young adults with normal hearing across unprocessed and vocoded listening conditions for multiple stimulus sets. Stimulus sets were lists of digits (1 to 9), consonant-vowel-consonant (CVC) words (chosen from a list of 60 words), and CVC nonwords (chosen from a list of 50 nonwords). Stimuli were unprocessed or vocoded with an eight-channel noise vocoder. To support interpretation of responses, words and nonwords were selected to minimize inclusion of multiple phonemes from within a confusion cluster. We also measured receptive vocabulary (Peabody Picture Vocabulary Test [PPVT-4]), sustained attention (test of variables of attention [TOVA]), and repetition speed for individual items from each stimulus set under both listening conditions.

RESULTS

Vocoding stimuli had no impact on serial recall of digits, but reduced memory span for words and nonwords. This reduction in memory span was attributed to an increase in phonological confusions for nonwords. However, memory span for vocoded word lists remained reduced even after accounting for common phonetic confusions, indicating that lexical status played an additional role across listening conditions. Principal components analysis found two components that explained 84% of the variance in memory span across conditions. Component one had similar load across all conditions, indicating that participants had an underlying memory capacity, which was common to all conditions. Component two was loaded by performance in the vocoded word and nonword conditions, representing the sensitivity of memory span to vocoding of these stimuli. The order in which participants completed listening conditions had a small effect on memory span that could not account for the effect of listening condition. Repetition speed was fastest for digits, slower for words, and slowest for nonwords. On average, vocoding slowed repetition speed for all stimuli, but repetition speed was not predictive of individual memory span. Vocabulary and attention showed no correlation with memory span.

CONCLUSIONS

Our results replicated previous findings that low quality auditory input can impair short-term memory, and demonstrated that this impairment is sensitive to stimulus set. Using multiple stimulus sets in degraded listening conditions can isolate memory capacity (in digit span) from impaired item identification (in word and nonword span), which may help characterize the relationship between memory and speech recognition in difficult listening conditions.

Neurophysiological Differences in Emotional Processing by Cochlear Implant Users, Extending Beyond the Realm of Speech

OBJECTIVE

Cochlear implants (CIs) restore a sense of hearing in deaf individuals. However, they do not transmit the acoustic signal with sufficient fidelity, leading to difficulties in recognizing emotions in voice and in music. The study aimed to explore the neurophysiological bases of these limitations.

DESIGN

Twenty-two adults (18 to 70 years old) with CIs and 22 age-matched controls with normal hearing participated. Event-related potentials (ERPs) were recorded in response to emotional bursts (happy, sad, or neutral) produced in each modality (voice or music) that were for the most part correctly identified behaviorally.

RESULTS

Compared to controls, the N1 and P2 components were attenuated and prolonged in CI users. To a smaller degree, N1 and P2 were also attenuated and prolonged in music compared to voice, in both populations. The N1-P2 complex was emotion-dependent (e.g., reduced and prolonged response to sadness), but this was also true in both populations. In contrast, the later portion of the response, between 600 and 850 ms, differentiated happy and sad from neutral stimuli in normal hearing but not in CI listeners.

CONCLUSIONS

The early portion of the ERP waveform reflected primarily the general reduction in sensory encoding by CI users (largely due to CI processing itself), whereas altered emotional processing (by CI users) could be found in the later portion of the ERP and extended beyond the realm of speech.

High-Variability Sentence Recognition in Long-Term Cochlear Implant Users: Associations With Rapid Phonological Coding and Executive Functioning

OBJECTIVES

The objective of the present study was to determine whether long-term cochlear implant (CI) users would show greater variability in rapid phonological coding skills and greater reliance on slow-effortful compensatory executive functioning (EF) skills than normal-hearing (NH) peers on perceptually challenging high-variability sentence recognition tasks. We tested the following three hypotheses: First, CI users would show lower scores on sentence recognition tests involving high speaker and dialect variability than NH controls, even after adjusting for poorer sentence recognition performance by CI users on a conventional low-variability sentence recognition test. Second, variability in fast-automatic rapid phonological coding skills would be more strongly associated with performance on high-variability sentence recognition tasks for CI users than NH peers. Third, compensatory EF strategies would be more strongly associated with performance on high-variability sentence recognition tasks for CI users than NH peers.

DESIGN

Two groups of children, adolescents, and young adults aged 9 to 29 years participated in this cross-sectional study: 49 long-term CI users (≥7 years) and 56 NH controls. All participants were tested on measures of rapid phonological coding (Children's Test of Nonword Repetition), conventional sentence recognition (Harvard Sentence Recognition Test), and two novel high-variability sentence recognition tests that varied the indexical attributes of speech (Perceptually Robust English Sentence Test Open-set test and Perceptually Robust English Sentence Test Open-set test-Foreign Accented English test). Measures of EF included verbal working memory (WM), spatial WM, controlled cognitive fluency, and inhibition concentration.

RESULTS

CI users scored lower than NH peers on both tests of high-variability sentence recognition even after conventional sentence recognition skills were statistically controlled. Correlations between rapid phonological coding and high-variability sentence recognition scores were stronger for the CI sample than for the NH sample even after basic sentence perception skills were statistically controlled. Scatterplots revealed different ranges and slopes for the relationship between rapid phonological coding skills and high-variability sentence recognition performance in CI users and NH peers. Although no statistically significant correlations between EF strategies and sentence recognition were found in the CI or NH sample after use of a conservative Bonferroni-type correction, medium to high effect sizes for correlations between verbal WM and sentence recognition in the CI sample suggest that further investigation of this relationship is needed.

CONCLUSIONS

These findings provide converging support for neurocognitive models that propose two channels for speech-language processing: a fast-automatic channel that predominates whenever possible and a compensatory slow-effortful processing channel that is activated during perceptually-challenging speech processing tasks that are not fully managed by the fast-automatic channel (ease of language understanding, framework for understanding effortful listening, and auditory neurocognitive model). CI users showed significantly poorer performance on measures of high-variability sentence recognition than NH peers, even after simple sentence recognition was controlled. Nonword repetition scores showed almost no overlap between CI and NH samples, and correlations between nonword repetition scores and high-variability sentence recognition were consistent with greater reliance on engagement of fast-automatic phonological coding for high-variability sentence recognition in the CI sample than in the NH sample. Further investigation of the verbal WM-sentence recognition relationship in CI users is recommended. Assessment of fast-automatic phonological processing and slow-effortful EF skills may provide a better understanding of speech perception outcomes in CI users in the clinical setting.

Rethinking Emergent Literacy in Children With Hearing Loss

Long-term literacy outcomes for children with hearing loss, particularly those with severe-to-profound deafness who are fitted with cochlear implants (CIs) lag behind those of children with normal hearing (NH). The causes for these long-term deficits are not fully clear, though differences in auditory access between children who use CIs and those with NH may be a partial cause. This paper briefly reviews the emergent literacy model as proposed by Whitehurst and Lonigan (1998). We then examine the development of each of Whitehurst and Lonigan’s identified factors in children who use CIs and how the extant knowledge of language and literacy development in children who use CIs may bear on the emergent literacy model. We then propose to modify the model for children who use CIs based on their unique developmental trajectories, influenced at least in part by their unique auditory access. We conclude with future directions for further development of an evidence-based emergent literacy model for children who use CIs and how this model could be used to inform intervention.

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 Higher Order Language Processing in Long-Term Cochlear Implant Users

Purpose The purpose of this study was to describe and explain individual differences in complex/higher order language processing in long-term cochlear implant (CI) users relative to normal-hearing (NH) peers. Method Measures of complex/higher order language processing indexed by the Clinical Evaluation of Language Fundamentals-Fourth Edition (CELF-4) Core Language subtests were obtained from 53 long-term (≥ 7 years) CI users aged 9-29 years and 60 NH controls who did not differ in age, gender, or nonverbal IQ. Vocabulary knowledge and fast, automatic language processing (rapid phonological coding, verbal rehearsal speed, and speech intelligibility) were also assessed. Results CI users showed weaker performance than NH controls on all CELF-4 Core Language subtests. These differences remained for Formulated Sentences and Recalling Sentences even when vocabulary knowledge was statistically controlled. About 50% of the CI sample scored within the range of the NH sample on Formulated Sentences and Recalling Sentences, while the remaining 50% scored well below the NH sample on these subtests. Vocabulary knowledge, rapid phonological coding, verbal rehearsal speed, and speech intelligibility were more strongly correlated with CELF-4 subtest scores in the CI sample than in the NH sample. Conclusions Weaknesses in complex, higher order language processing shown by a subgroup of CI users compared to NH peers may result from delays in fast, automatic processing of language. These at-risk domains of language functioning could serve as targets for novel interventions for deaf children who experience suboptimal spoken language outcomes following cochlear implantation.

Speech-in-Noise Perception in Children With Cochlear Implants, Hearing Aids, Developmental Language Disorder and Typical Development: The Effects of Linguistic and Cognitive Abilities

Children with hearing loss, and those with language disorders, can have excellent speech recognition in quiet, but still experience unique challenges when listening to speech in noisy environments. However, little is known about how speech-in-noise (SiN) perception relates to individual differences in cognitive and linguistic abilities in these children. The present study used the Norwegian version of the Hearing in Noise Test (HINT) to investigate SiN perception in 175 children aged 5.5-12.9 years, including children with cochlear implants (CI, n = 64), hearing aids (HA, n = 37), developmental language disorder (DLD, n = 16) and typical development (TD, n = 58). Further, the study examined whether general language ability, verbal memory span, non-verbal IQ and speech perception of monosyllables and sentences in quiet were predictors of performance on the HINT. To allow comparisons across ages, scores derived from age-based norms were used for the HINT and the tests of language and cognition. There were significant differences in SiN perception between all the groups except between the HA and DLD groups, with the CI group requiring the highest signal-to-noise ratios (i.e., poorest performance) and the TD group requiring the lowest signal-to-noise ratios. For the full sample, language ability explained significant variance in HINT performance beyond speech perception in quiet. Follow-up analyses for the separate groups revealed that language ability was a significant predictor of HINT performance for children with CI, HA, and DLD, but not for children with TD. Memory span and IQ did not predict variance in SiN perception when language ability and speech perception in quiet were taken into account. The finding of a robust relation between SiN perception and general language skills in all three clinical groups call for further investigation into the mechanisms that underlie this association.

Rhyme Awareness in Children With Normal Hearing and Children With Cochlear Implants: An Exploratory Study

Phonological awareness is a critical component of phonological processing that predicts children’s literacy outcomes. Phonological awareness skills enable children to think about the sound structure of words and facilitates decoding and the analysis of words during spelling. Past research has shown that children’s vocabulary knowledge and working memory capacity are associated with their phonological awareness skills. Linguistic characteristics of words, such as phonological neighborhood density and orthography congruency have also been found to influence children’s performance in phonological awareness tasks. Literacy is a difficult area for deaf and hard of hearing children, who have poor phonological awareness skills. Although cochlear implantation (CI) has been found to improve these children’s speech and language outcomes, limited research has investigated phonological awareness in children with CI. Rhyme awareness is the first level of phonological awareness to develop in children with normal hearing (NH). The current study investigates whether rhyme awareness in children with NH (n = 15, median age = 5; 5, IQR = 11 ms) and a small group of children with CI (n = 6, median age = 6; 11.5, IQR = 3.75 ms) is associated with individual differences in vocabulary and working memory. Using a rhyme oddity task, well-controlled for perceptual similarity, we also explored whether children’s performance was associated with linguistic characteristics of the task items (e.g., rhyme neighborhood density, orthographic congruency). Results indicate that there is an association between vocabulary and working memory and performance in a rhyme awareness task in NH children. Only working memory was correlated with rhyme awareness performance in CI children. Linguistic characteristics of the task items, on the other hand, were not found to be associated with success. Implications of the results and future directions are discussed.

Auditory memory span in Mandarin-speaking preschoolers with congenital hearing loss: Impact of task structure

Objective: The current research was conducted to test the prediction that children who have hearing loss and are developing spoken language can perform at the same level as hearing children in an auditory memory span task if actual production of speech is excluded from task requirement.Method: A listen-and-point digit span task and two sub-tests of Wechsler Intelligence Scale for Children-IV (Verbal Digit Span and Matrix Reasoning) were administered to thirty hearing children and thirty-three children with hearing loss. A language assessment instrument for Mandarin-speaking preschool children was also administered to the participants with hearing loss.Results: The listen-and-point task not only correlated with the Verbal Digit Span sub-test, but also correlated with the comprehension sub-test of the language assessment instrument. The size of auditory memory span was similar in both groups of participants in the listen-and-point task. Moreover, the memory span estimated in the listen-and-point task was smaller than that estimated in the Verbal Digit Span task. The correlation coefficients between chronological age and the listen-and-point task were also similar in both groups of children.Conclusions: When speech processes are not required in an auditory working memory task, demand for the phonological loop is reduced and the children with hearing loss are able to perform as well as the hearing children. Moreover, the auditory memory span develops at the same rate for the children with hearing loss as for the hearing children.

Predicting Speech Recognition Using the Speech Intelligibility Index and Other Variables for Cochlear Implant Users

Purpose Although the speech intelligibility index (SII) has been widely applied in the field of audiology and other related areas, application of this metric to cochlear implants (CIs) has yet to be investigated. In this study, SIIs for CI users were calculated to investigate whether the SII could be an effective tool for predicting speech perception performance in a population with CI. Method Fifteen pre- and postlingually deafened adults with CI participated. Speech recognition scores were measured using the AzBio sentence lists. CI users also completed questionnaires and performed psychoacoustic (spectral and temporal resolution) and cognitive function (digit span) tests. Obtained SIIs were compared with predicted SIIs using a transfer function curve. Correlation and regression analyses were conducted on perceptual and demographic predictor variables to investigate the association between these factors and speech perception performance. Result Because of the considerably poor hearing and large individual variability in performance, the SII did not predict speech performance for this CI group using the traditional calculation. However, new SII models were developed incorporating predictive factors, which improved the accuracy of SII predictions in listeners with CI. Conclusion Conventional SII models are not appropriate for predicting speech perception scores for CI users. Demographic variables (aided audibility and duration of deafness) and perceptual-cognitive skills (gap detection and auditory digit span outcomes) are needed to improve the use of the SII for listeners with CI. Future studies are needed to improve our CI-corrected SII model by considering additional predictive factors. Supplemental Material https://doi.org/10.23641/asha.8057003.

Evaluating Pediatric Cochlear Implant Users' Encoding, Storage, and Retrieval Strategies in Verbal Working Memory

Purpose The current study adopts a systematic approach to the examination of working memory components in pediatric cochlear implant (CI) users by separately assessing contributions of encoding, storage, and retrieval. Method Forty-nine long-term CI users and 56 typically hearing controls completed forward and backward span tasks with 3 stimulus sets: visually presented digits, pictures of concrete nouns, and novel symbols. In addition, measures associated with each memory stage were collected: Rapid digit naming provided an estimate of phonological recoding speed, nonword repetition assessed the robustness of representations within phonological storage, and vocabulary knowledge (as measured by the Peabody Picture Vocabulary Test; Dunn & Dunn, 1997 ) estimated redintegration abilities during retrieval. Results Linear mixed modeling revealed that digit naming speed and vocabulary knowledge were consistently related to short-term and working memory span in both CI users and typically hearing controls. However, nonword repetition only contributed to the model for short-term memory. Conclusions Nonword repetition, an index of phonological storage, explained little of the individual variability inworking memory differences between CI users and typically hearing peers. On the other hand, individual differences in encoding and retrieval explained a significant amount of outcome variability in both short-term and working memory tasks. Differences between CI users and typically hearing peers in working memory therefore appear to reflect process components of encoding and retrieval and not simply differences in memory storage. Supplemental Material https://doi.org/10.23641/asha.7849394.

Verbal Learning and Memory in Early-Implanted, Prelingually Deaf Adolescent and Adult Cochlear Implant Users

Purpose The purpose of this study was to investigate the information-processing strategies of early-implanted, prelingually deaf cochlear implant (CI) users with the California Verbal Learning Test-Second Edition (CVLT-II; Delis, Kramer, Kaplan, & Ober, 2000 ), a well-established normed measure of verbal learning and memory used in neuropsychological assessments of memory loss. Method Verbal learning and memory skills were compared in 20 older adolescent and young adult prelingually deaf long-term early-implanted CI users and their 24 normal hearing (NH) peers using the CVLT-II, a widely used multitrial free recall test of verbal learning and memory. Results On average, CI users recalled fewer words than their NH peers across the immediate, delayed, and cued recall trials of the CVLT-II but were comparable to their NH peers on yes/no recognition memory. CI users showed little evidence of semantic clustering of words during free recall but greater serial clustering compared to their NH peers, suggesting fundamental disturbances in automatic semantic activation of words from long-term memory. No differences were found in verbal memory between CI users and their NH peers on measures of retroactive interference and encoding/retrieval interactions. Performance on the 2nd word list of the CVLT-II (List B) and amount of semantic clustering of words during recall were correlated with sentence recognition in the CI group. Conclusion Study findings demonstrate significant differences in free recall performance and information-processing strategies that early-implanted, prelingually deaf CI users use to encode, organize, store, and retrieve spoken words in conventional verbal list learning paradigms, compared to their NH peers. Because verbal learning and memory are core foundational processes routinely used in daily functioning for a wide range of neurocognitive and language processing operations, these findings suggest potential domains for assessment and novel interventions to promote the development of optimal outcomes in prelingually deaf early-implanted long-term CI users.

Effect of fine and gross motor training or motor imagery, delivered via novel or routine modes, on cognitive function

There is extensive literature linking motor activity to cognitive effects at various stages in life, promoting both development and the reduction of aging associated pathologies. It is unclear whether the benefits of this activity on the cognitive level are associated with brain functions that are necessary for their performance or recurrence of activity or type of activity itself. The aim of this study was to evaluate whether the type of motor activity (fine, gross, and motor imagery) in two modes (novel and routine) can affect cognitive functions such as attention, executive functions, and praxis in college students. A 2 × 3 factorial design with repeated measures was used without a control group and pre- and post-training evaluation. Fifty-three young people (14 men and 39 women) participated, with mean age of 18.94 years (SD = 1.61 years) and were divided into six groups. Each of the groups performed relevant training 20 minutes per day for five days depending on the group. Measures were taken pre and post-training for attention tests, attention span, working memory, visual constructive skills, procedural memory, and motor skills. The results show a "learning effect" from the exposure to the tests in measurements after training. It was also found that between groups, there is a difference in some of the variables of procedural memory (number of errors) and working memory. More extensive training could better reflect the effects of the training, and longitudinal evaluation could show the rate of change of functions. The main clinical implication could be the evaluation of training programs for recovery and motor training in cerebral plasticity having effect on the cognitive aspects.

Visual habituation in deaf and hearing infants

Early cognitive development relies on the sensory experiences that infants acquire as they explore their environment. Atypical experience in one sensory modality from birth may result in fundamental differences in general cognitive abilities. The primary aim of the current study was to compare visual habituation in infants with profound hearing loss, prior to receiving cochlear implants (CIs), and age-matched peers with typical hearing. Two complementary measures of cognitive function and attention maintenance were assessed: the length of time to habituate to a visual stimulus, and look-away rate during habituation. Findings revealed that deaf infants were slower to habituate to a visual stimulus and demonstrated a lower look-away rate than hearing infants. For deaf infants, habituation measures correlated with language outcomes on standardized assessments before cochlear implantation. These findings are consistent with prior evidence suggesting that habituation and look-away rates reflect efficiency of information processing and may suggest that deaf infants take longer to process visual stimuli relative to the hearing infants. Taken together, these findings are consistent with the hypothesis that hearing loss early in infancy influences aspects of general cognitive functioning.

Assessing Cognitive Abilities in High-Performing Cochlear Implant Users

Despite being considered one of the most successful neural prostheses, cochlear implants (CIs) provide recipients with a wide range of speech perception performance. While some CI users can understand speech in the absence of visual cues, other recipients exhibit more limited speech perception. Cognitive skills have been documented as a contributor to complex auditory processing, such as language understanding; however, there are no normative data for existing standardized clinical tests assessing cognitive abilities in CI users. Here, we assess the impact of modality of presentation (i.e., auditory-visual versus visual) for the administration of working memory tests in high-performing CI users in addition to measuring processing speed, cognitive efficiency and intelligence quotient (IQ). Second, we relate performance on these cognitive measures to clinical CI speech perception outcomes.

Methods: Twenty one post-lingually deafened, high-performing, adult CI users [age range: 52–88 years; 3 unilateral CI, 13 bimodal (i.e., CI with contralateral hearing aid), 5 bilateral CI] with clinical speech perception scores (i.e., AzBio sentences in quiet for the first-ear CI) of ≥60% were recruited. A cognitive test battery assessing auditory-visual working memory (AVWM), visual working memory (VWM), processing speed, cognitive efficiency and IQ was administered, in addition to clinical measures of speech perception in quiet (i.e., AzBio sentences in quiet). AzBio sentences were assessed in two conditions: first-ear CI only, and best-aided everyday wearing condition. Subjects also provided self-reported measures of performance and benefit from their CI using standardized materials, including the Glasgow Benefit Inventory (GBI) and the Nijmegen Cochlear Implant questionnaire (NCIQ).

Results: High-performing CI users demonstrated greater VWM than AVWM recall. VWM was positively related to AzBio scores when measured in the first-ear CI only. AVWM, processing speed, cognitive efficiency, and IQ did not relate to either measure of speech perception (i.e., first-ear CI or best-aided conditions). Subjects’ self-reported benefit as measured by the GBI predicted best-aided CI speech perception performance.

Conclusion: In high-performing CI recipients, visual presentation of working memory tests may improve our assessment of cognitive function.