Audiovisual Processing Skills Before Cochlear Implantation Predict Postoperative Speech Recognition in Adults.

OBJECTIVES: Adults with hearing loss (HL) demonstrate greater benefits of adding visual cues to auditory cues (i.e., "visual enhancement" [VE]) during recognition of speech presented in a combined audiovisual (AV) fashion when compared with normal-hearing peers. For patients with moderate-to-profound sensorineural HL who receive cochlear implants (CIs), it is unclear whether the restoration of audibility results in a decrease in the VE provided by visual cues during AV speech recognition. Moreover, it is unclear whether increased VE during the experience of HL before CI is beneficial or maladaptive to ultimate speech recognition abilities after implantation. It is conceivable that greater VE before implantation contributes to the enormous variability in speech recognition outcomes demonstrated among patients with CIs. This study took a longitudinal approach to test two hypotheses: (H1) Adult listeners with HL who receive CIs would demonstrate a decrease in VE after implantation; and (H2) The magnitude of pre-CI VE would predict post-CI auditory-only speech recognition abilities 6 months after implantation, with the direction of that relation supporting a beneficial, redundant, or maladaptive effect on outcomes. DESIGN: Data were collected from 30 adults at two time points: immediately before CI surgery and 6 months after device activation. Pre-CI speech recognition performance was measured in auditory-only (A-only), visual-only, and combined AV fashion for City University of New York (CUNY) sentences. Scores of VE during AV sentence recognition were computed. At 6 months after CI activation, participants were again tested on CUNY sentence recognition in the same conditions as pre-CI. H1 was tested by comparing post- versus pre-CI VE scores. At 6 months of CI use, additional open-set speech recognition measures were also obtained in the A-only condition, including isolated words, words in meaningful AzBio sentences, and words in AzBio sentences in multitalker babble. To test H2, correlation analyses were performed to assess the relation between post-CI A-only speech recognition scores and pre-CI VE scores. RESULTS: Inconsistent with H1, after CI, participants did not demonstrate a significant decrease in VE scores. Consistent with H2, preoperative VE scores positively predicted postoperative scores of A-only sentence recognition for both sentences in quiet and in babble (rho = 0.40 to 0.45, p < 0.05), supporting a beneficial effect of pre-CI VE on post-CI auditory outcomes. Pre-CI VE was not significantly related to post-CI isolated word recognition. The raw pre-CI CUNY AV scores also predicted post-CI A-only speech recognition scores to a similar degree as VE scores. CONCLUSIONS: After implantation, CI users do not demonstrate a decrease in VE from before surgery. The degree of VE during AV speech recognition before CI positively predicts A-only sentence recognition outcomes after implantation, suggesting the potential value of AV testing of CI patients preoperatively to help predict and set expectations for postoperative outcomes.

Using Complex Networks in the Hearing Sciences.

In this Point of View, we review a number of recent discoveries from the emerging, interdisciplinary field of Network Science , which uses graph theoretic techniques to understand complex systems. In the network science approach, nodes represent entities in a system, and connections are placed between nodes that are related to each other to form a web-like network . We discuss several studies that demonstrate how the micro-, meso-, and macro-level structure of a network of phonological word-forms influence spoken word recognition in listeners with normal hearing and in listeners with hearing loss. Given the discoveries made possible by this new approach and the influence of several complex network measures on spoken word recognition performance we argue that speech recognition measures-originally developed in the late 1940s and routinely used in clinical audiometry-should be revised to reflect our current understanding of spoken word recognition. We also discuss other ways in which the tools of network science can be used in Speech and Hearing Sciences and Audiology more broadly.

Preoperative Visual Measures of Verbal Learning and Memory and their Relations to Speech Recognition After Cochlear Implantation.

OBJECTIVES: This study examined the performance of a group of adult cochlear implant (CI) candidates (CIC) on visual tasks of verbal learning and memory. Preoperative verbal learning and memory abilities of the CIC group were compared with a group of older normal-hearing (ONH) control participants. Relations between preoperative verbal learning and memory measures and speech recognition outcomes after 6 mo of CI use were also investigated for a subgroup of the CICs. DESIGN: A group of 80 older adult participants completed a visually presented multitrial free recall task. Measures of word recall, repetition learning, and the use of self-generated organizational strategies were collected from a group of 49 CICs, before cochlear implantation, and a group of 31 ONH controls. Speech recognition outcomes were also collected from a subgroup of 32 of the CIC participants who returned for testing 6 mo after CI activation. RESULTS: CICs demonstrated poorer verbal learning performance compared with the group of ONH control participants. Among the preoperative verbal learning and memory measures, repetition learning slope and measures of self-generated organizational clustering strategies were the strongest predictors of post-CI speech recognition outcomes. CONCLUSIONS: Older adult CI candidates present with verbal learning and memory deficits compared with older adults without hearing loss, even on visual tasks that are independent from the direct effects of audibility. Preoperative verbal learning and memory processes reflecting repetition learning and self-generated organizational strategies in free recall were associated with speech recognition outcomes 6 months after implantation. The pattern of results suggests that visual measures of verbal learning may be a useful predictor of outcomes in postlingual adult CICs.

Functional hearing quality in prelingually deaf school-age children and adolescents with cochlear implants.

OBJECTIVE: This study investigated differences in functional hearing quality between youth with cochlear implants (CIs) and normal hearing (NH) peers, as well as associations between functional hearing quality and audiological measures, speech perception, language and executive functioning (EF). DESIGN: Youth with CIs and NH peers completed measures of audiological functioning, speech perception, language and EF. Parents completed the Quality of Hearing Scale (QHS), a questionnaire measure of functional hearing quality. STUDY SAMPLE: Participants were 43 prelingually-deaf, early-implanted, long-term CI users and 43 NH peers aged 7-17 years. RESULTS: Compared to NH peers, youth with CIs showed poorer functional hearing quality on the QHS Speech, Localization, and Sounds subscales and more hearing effort on the QHS Effort subscale. QHS scores did not correlate significantly with audiological/hearing history measures but were significantly correlated with most speech perception, language and EF scores in the CI sample. In the NH sample, QHS scores were uncorrelated with speech perception and language and were inconsistently correlated with EF. CONCLUSIONS: The QHS is a valid measure of functional hearing quality that is distinct from office-based audiometric or hearing history measures. Functional hearing outcomes are associated with speech-language and EF outcomes in CI users.

Family Environment in Children With Hearing Aids and Cochlear Implants: Associations With Spoken Language, Psychosocial Functioning, and Cognitive Development.

OBJECTIVES: To examine differences in family environment and associations between family environment and key speech, language, and cognitive outcomes in samples of children with normal hearing and deaf and hard-of-hearing (DHH) children who use hearing aids and cochlear implants. DESIGN: Thirty families of children with normal hearing (n = 10), hearing aids (n = 10), or cochlear implants (n = 10) completed questionnaires evaluating executive function, social skills, and problem behaviors. Children's language and receptive vocabulary were evaluated using standardized measures in the children's homes. In addition, families were administered a standardized in-home questionnaire and observational assessment regarding the home environment. RESULTS: Family environment overall was similar across hearing level and sensory aid, although some differences were found on parental responsivity and physical environment. The level of supportiveness and enrichment within family relationships accounted for much of the relations between family environment and the psychosocial and neurocognitive development of DHH children. In contrast, the availability of objects and experiences to stimulate learning in the home was related to the development of spoken language. CONCLUSIONS: Whereas broad characteristics of the family environments of DHH children may not differ from those of hearing children, variability in family functioning is related to DHH children's at-risk speech, language, and cognitive outcomes. Results support the importance of further research to clarify and explain these relations, which might suggest novel methods and targets of family-based interventions to improve developmental outcomes.

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.

Extrinsic Cognitive Load Impairs Spoken Word Recognition in High- and Low-Predictability Sentences.

OBJECTIVES: Listening effort (LE) induced by speech degradation reduces performance on concurrent cognitive tasks. However, a converse effect of extrinsic cognitive load on recognition of spoken words in sentences has not been shown. The aims of the present study were to (a) examine the impact of extrinsic cognitive load on spoken word recognition in a sentence recognition task and (b) determine whether cognitive load and/or LE needed to understand spectrally degraded speech would differentially affect word recognition in high- and low-predictability sentences. Downstream effects of speech degradation and sentence predictability on the cognitive load task were also examined. DESIGN: One hundred twenty young adults identified sentence-final spoken words in high- and low-predictability Speech Perception in Noise sentences. Cognitive load consisted of a preload of short (low-load) or long (high-load) sequences of digits, presented visually before each spoken sentence and reported either before or after identification of the sentence-final word. LE was varied by spectrally degrading sentences with four-, six-, or eight-channel noise vocoding. Level of spectral degradation and order of report (digits first or words first) were between-participants variables. Effects of cognitive load, sentence predictability, and speech degradation on accuracy of sentence-final word identification as well as recall of preload digit sequences were examined. RESULTS: In addition to anticipated main effects of sentence predictability and spectral degradation on word recognition, we found an effect of cognitive load, such that words were identified more accurately under low load than high load. However, load differentially affected word identification in high- and low-predictability sentences depending on the level of sentence degradation. Under severe spectral degradation (four-channel vocoding), the effect of cognitive load on word identification was present for high-predictability sentences but not for low-predictability sentences. Under mild spectral degradation (eight-channel vocoding), the effect of load was present for low-predictability sentences but not for high-predictability sentences. There were also reliable downstream effects of speech degradation and sentence predictability on recall of the preload digit sequences. Long digit sequences were more easily recalled following spoken sentences that were less spectrally degraded. When digits were reported after identification of sentence-final words, short digit sequences were recalled more accurately when the spoken sentences were predictable. CONCLUSIONS: Extrinsic cognitive load can impair recognition of spectrally degraded spoken words in a sentence recognition task. Cognitive load affected word identification in both high- and low-predictability sentences, suggesting that load may impact both context use and lower-level perceptual processes. Consistent with prior work, LE also had downstream effects on memory for visual digit sequences. Results support the proposal that extrinsic cognitive load and LE induced by signal degradation both draw on a central, limited pool of cognitive resources that is used to recognize spoken words in sentences under adverse listening conditions.

Psychosocial Outcomes in Long-Term Cochlear Implant Users.

OBJECTIVES: The objectives of this study were to investigate psychosocial outcomes in a sample of prelingually deaf, early-implanted children, adolescents, and young adults who are long-term cochlear implant (CI) users and to examine the extent to which language and executive functioning predict psychosocial outcomes. DESIGN: Psychosocial outcomes were measured using two well-validated, parent-completed checklists: the Behavior Assessment System for Children and the Conduct Hyperactive Attention Problem Oppositional Symptom. Neurocognitive skills were measured using gold standard, performance-based assessments of language and executive functioning. RESULTS: CI users were at greater risk for clinically significant deficits in areas related to attention, oppositional behavior, hyperactivity-impulsivity, and social-adaptive skills compared with their normal-hearing peers, although the majority of CI users scored within average ranges relative to Behavior Assessment System for Children norms. Regression analyses revealed that language, visual-spatial working memory, and inhibition-concentration skills predicted psychosocial outcomes. CONCLUSIONS: Findings suggest that underlying delays and deficits in language and executive functioning may place some CI users at a risk for difficulties in psychosocial adjustment.

Verbal Learning and Memory After Cochlear Implantation in Postlingually Deaf Adults: Some New Findings with the CVLT-II.

OBJECTIVES: Despite the importance of verbal learning and memory in speech and language processing, this domain of cognitive functioning has been virtually ignored in clinical studies of hearing loss and cochlear implants in both adults and children. In this article, we report the results of two studies that used a newly developed visually based version of the California Verbal Learning Test-Second Edition (CVLT-II), a well-known normed neuropsychological measure of verbal learning and memory. DESIGN: The first study established the validity and feasibility of a computer-controlled visual version of the CVLT-II, which eliminates the effects of audibility of spoken stimuli, in groups of young normal-hearing and older normal-hearing (ONH) adults. A second study was then carried out using the visual CVLT-II format with a group of older postlingually deaf experienced cochlear implant (ECI) users (N = 25) and a group of ONH controls (N = 25) who were matched to ECI users for age, socioeconomic status, and nonverbal IQ. In addition to the visual CVLT-II, subjects provided data on demographics, hearing history, nonverbal IQ, reading fluency, vocabulary, and short-term memory span for visually presented digits. ECI participants were also tested for speech recognition in quiet. RESULTS: The ECI and ONH groups did not differ on most measures of verbal learning and memory obtained with the visual CVLT-II, but deficits were identified in ECI participants that were related to recency recall, the buildup of proactive interference, and retrieval-induced forgetting. Within the ECI group, nonverbal fluid IQ, reading fluency, and resistance to the buildup of proactive interference from the CVLT-II consistently predicted better speech recognition outcomes. CONCLUSIONS: Results from this study suggest that several underlying foundational neurocognitive abilities are related to core speech perception outcomes after implantation in older adults. Implications of these findings for explaining individual differences and variability and predicting speech recognition outcomes after implantation are discussed.

Verbal learning and memory in prelingually deaf children with cochlear implants.

OBJECTIVE: Deaf children with cochlear implants (CIs) show poorer verbal working memory compared to normal-hearing (NH) peers, but little is known about their verbal learning and memory (VLM) processes involving multi-trial free recall. DESIGN: Children with CIs were compared to NH peers using the California Verbal Learning Test for Children (CVLT-C). STUDY SAMPLE: Participants were 21 deaf (before age 6 months) children (6-16 years old) implanted prior to age 3 years, and 21 age-IQ matched NH peers. RESULTS: Results revealed no differences between groups in number of words recalled. However, CI users showed a pattern of increasing use of serial clustering strategies across learning trials, whereas NH peers decreased their use of serial clustering strategies. In the CI sample (but not in the NH sample), verbal working memory test scores were related to resistance to the build-up of proactive interference, and sentence recognition was associated with performance on the first exposure to the word list and to the use of recency recall strategies. CONCLUSIONS: Children with CIs showed robust evidence of VLM comparable to NH peers. However, their VLM processing (especially recency and proactive interference) was related to speech perception outcomes and verbal WM in different ways from NH peers.

Supra-Segmental Changes in Speech Production as a Result of Spectral Feedback Degradation: Comparison with Lombard Speech.

Perturbations to acoustic speech feedback have been typically localized to specific phonetic characteristics, for example, fundamental frequency (F0) or the first two formants (F1/F2), or affect all aspects of the speech signal equally, for example, via the addition of background noise. This paper examines the consequences of a more selective global perturbation: real-time cochlear implant (CI) simulation of acoustic speech feedback. Specifically, we examine the potential similarity between speakers' response to noise vocoding and the characteristics of Lombard speech. An acoustic analysis of supra-segmental characteristics in speaking rate, F0 production, and voice amplitude revealed changes that paralleled the Lombard effect in some domains but not others. Two studies of speech intelligibility complemented the acoustic analysis, finding that intelligibility significantly decreased as a result of CI simulation of speaker feedback. Together, the results point to differences in speakers' responses to these two superficially similar feedback manipulations. In both cases we see a complex, multi-faceted behavior on the part of talkers. We argue that more instances of global perturbation and broader response assessment are needed to determine whether such complexity is present in other feedback manipulations or if it represents a relatively rare exception to the typical compensatory feedback response.

Some Neurocognitive Correlates of Noise-Vocoded Speech Perception in Children With Normal Hearing: A Replication and Extension of ).

OBJECTIVES: Noise-vocoded speech is a valuable research tool for testing experimental hypotheses about the effects of spectral degradation on speech recognition in adults with normal hearing (NH). However, very little research has utilized noise-vocoded speech with children with NH. Earlier studies with children with NH focused primarily on the amount of spectral information needed for speech recognition without assessing the contribution of neurocognitive processes to speech perception and spoken word recognition. In this study, we first replicated the seminal findings reported by ) who investigated effects of lexical density and word frequency on noise-vocoded speech perception in a small group of children with NH. We then extended the research to investigate relations between noise-vocoded speech recognition abilities and five neurocognitive measures: auditory attention (AA) and response set, talker discrimination, and verbal and nonverbal short-term working memory. DESIGN: Thirty-one children with NH between 5 and 13 years of age were assessed on their ability to perceive lexically controlled words in isolation and in sentences that were noise-vocoded to four spectral channels. Children were also administered vocabulary assessments (Peabody Picture Vocabulary test-4th Edition and Expressive Vocabulary test-2nd Edition) and measures of AA (NEPSY AA and response set and a talker discrimination task) and short-term memory (visual digit and symbol spans). RESULTS: Consistent with the findings reported in the original ) study, we found that children perceived noise-vocoded lexically easy words better than lexically hard words. Words in sentences were also recognized better than the same words presented in isolation. No significant correlations were observed between noise-vocoded speech recognition scores and the Peabody Picture Vocabulary test-4th Edition using language quotients to control for age effects. However, children who scored higher on the Expressive Vocabulary test-2nd Edition recognized lexically easy words better than lexically hard words in sentences. Older children perceived noise-vocoded speech better than younger children. Finally, we found that measures of AA and short-term memory capacity were significantly correlated with a child's ability to perceive noise-vocoded isolated words and sentences. CONCLUSIONS: First, we successfully replicated the major findings from the ) study. Because familiarity, phonological distinctiveness and lexical competition affect word recognition, these findings provide additional support for the proposal that several foundational elementary neurocognitive processes underlie the perception of spectrally degraded speech. Second, we found strong and significant correlations between performance on neurocognitive measures and children's ability to recognize words and sentences noise-vocoded to four spectral channels. These findings extend earlier research suggesting that perception of spectrally degraded speech reflects early peripheral auditory processes, as well as additional contributions of executive function, specifically, selective attention and short-term memory processes in spoken word recognition. The present findings suggest that AA and short-term memory support robust spoken word recognition in children with NH even under compromised and challenging listening conditions. These results are relevant to research carried out with listeners who have hearing loss, because they are routinely required to encode, process, and understand spectrally degraded acoustic signals.

Speech rate, rate-matching, and intelligibility in early-implanted cochlear implant users.

An important speech-language outcome for deaf people with cochlear implants is speech intelligibility-how well their speech is understood by others, which also affects social functioning. Beyond simply uttering recognizable words, other speech-language skills may affect communicative competence, including rate-matching or converging toward interlocutors' speech rates. This initial report examines speech rate-matching and its relations to intelligibility in 91 prelingually deaf cochlear implant users and 93 typically hearing peers age 3 to 27 years. Live-voice spoken sentences were repeated and later transcribed by multiple hearing listeners. Speech intelligibility was calculated as proportions of words correctly transcribed. For speech rate-matching measures, speech rates (syllables/s) were normalized as percentages faster or slower than examiners' speech rates. Cochlear implant users had slower speech rates, less accurate and less consistent rate-matching, and poorer speech intelligibility than hearing peers. Among cochlear implant users, speech rate and rate-matching were correlated with intelligibility: faster talkers and better rate-matchers were more intelligible. Rate-matching and intelligibility improved during preschool, with cochlear implant users delayed by about a year compared to hearing peers. By school-age, rate-matching and intelligibility were good overall, but delays persisted for many cochlear implant users. Interventions targeting rate-matching skills are therefore warranted in speech-language therapy for this population.

Speech Intelligibility and Psychosocial Functioning in Deaf Children and Teens with Cochlear Implants.

Deaf children with cochlear implants (CIs) are at risk for psychosocial adjustment problems, possibly due to delayed speech-language skills. This study investigated associations between a core component of spoken-language ability-speech intelligibility-and the psychosocial development of prelingually deaf CI users. Audio-transcription measures of speech intelligibility and parent reports of psychosocial behaviors were obtained for two age groups (preschool, school-age/teen). CI users in both age groups scored more poorly than typically hearing peers on speech intelligibility and several psychosocial scales. Among preschool CI users, five scales were correlated with speech intelligibility: functional communication, attention problems, atypicality, withdrawal, and adaptability. These scales and four additional scales were correlated with speech intelligibility among school-age/teen CI users: leadership, activities of daily living, anxiety, and depression. Results suggest that speech intelligibility may be an important contributing factor underlying several domains of psychosocial functioning in children and teens with CIs, particularly involving socialization, communication, and emotional adjustment.

Long-term musical experience and auditory and visual perceptual abilities under adverse conditions.

Musicians have been shown to have enhanced speech perception in noise skills. It is unclear whether these improvements are limited to the auditory modality, as no research has examined musicians' visual perceptual abilities under degraded conditions. The current study examined associations between long-term musical experience and visual perception under noisy or degraded conditions. The performance of 11 musicians and 11 age-matched nonmusicians was compared on several auditory and visual perceptions in noise measures. Auditory perception tests included speech-in-noise tests and an environmental sound in noise test. Visual perception tasks included a fragmented sentences task, an object recognition task, and a lip-reading measure. Participants' vocabulary knowledge and nonverbal reasoning abilities were also assessed. Musicians outperformed nonmusicians on the speech perception in noise measures as well as the visual fragmented sentences task. Musicians also displayed better vocabulary knowledge in comparison to nonmusicians. Associations were found between perception of speech and visually degraded text. The findings show that long-term musical experience is associated with modality-general improvements in perceptual abilities. Possible systems supporting musicians' perceptual abilities are discussed.

Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production.

OBJECTIVE: To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. DESIGN: Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). RESULTS: Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. CONCLUSIONS: Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks.

Modulating executive functioning: trait motivational reactivity and resting HRV.

This study assessed relationships among individual differences in trait motivational reactivity, executive functioning, and neurovisceral regulation of emotion and attention indexed via resting heart rate variability (rHRV). We derived predictions regarding these relationships according to neurovisceral neural network theory. Because lower rHRV has been suggested as an endophenotype of less adaptive behaviour, low rHRV individuals were predicted to have high aversive and low appetitive trait motivational reactivity, while high rHRV individuals were predicted to have high reactivity in both appetitive and aversive motivational systems. These predictions were supported. Motivational reactivity also was related to executive functioning deficits, although the pattern of results was not in the predicted direction. Results suggest that trait motivational reactivity scores are related to visceral responses proposed in the neurovisceral integration circuit as well as in the modulation of these responses by higher-order cognitive control systems related to executive function.

Concept formation skills in long-term cochlear implant users.

This study investigated if a period of auditory sensory deprivation followed by degraded auditory input and related language delays affects visual concept formation skills in long-term prelingually deaf cochlear implant (CI) users. We also examined if concept formation skills are mediated or moderated by other neurocognitive domains (i.e., language, working memory, and executive control). Relative to normally hearing (NH) peers, CI users displayed significantly poorer performance in several specific areas of concept formation, especially when multiple comparisons and relational concepts were components of the task. Differences in concept formation between CI users and NH peers were fully explained by differences in language and inhibition-concentration skills. Language skills were also found to be more strongly related to concept formation in CI users than in NH peers. The present findings suggest that complex relational concepts may be adversely affected by a period of early prelingual deafness followed by access to underspecified and degraded sound patterns and spoken language transmitted by a CI. Investigating a unique clinical population such as early-implanted prelingually deaf children with CIs can provide new insights into foundational brain-behavior relations and developmental processes.

Influence of early linguistic experience on regional dialect categorization by an adult cochlear implant user: a case study.

To investigate the ability of a cochlear implant user to categorize talkers by region of origin and examine the influence of prior linguistic experience on the perception of regional dialect variation. A postlingually deafened adult cochlear implant user from the Southern region of the United States completed a six-alternative forced-choice dialect categorization task. The cochlear implant user was most accurate at categorizing unfamiliar talkers from his own region and another familiar dialect region, and least accurate at categorizing talkers from less familiar regions. Although the dialect-specific information made available by a cochlear implant may be degraded compared with information available to normal-hearing listeners, this experienced cochlear implant user was able to reliably categorize unfamiliar talkers by region of origin. The participant made use of dialect-specific acoustic-phonetic information in the speech signal and previously stored knowledge of regional dialect differences from early exposure before implantation despite an early hearing loss.