Cochlear Implant Normal Hearing Research Articles

Spanish translation and validation of the Music-Related Quality of Life Questionnaire (MuRQoL) in postlingually deaf cochlear implant users

PurposeThe aim of this study was to translate and validate the “Music-Related Quality of Life Questionnaire” into Spanish (sMuRQoL) and assess its convergent validity and discriminative capacity by comparing its scores with the outcomes of the musical perception test Meludia.MethodsThe sMuRQoL was completed by 129 patients: 55 cochlear implant (CI) users and 74 normal hearing (NH) individuals. Conducted in this study were an exploratory factor analysis, an evaluation of internal consistency, an assessment of score stability through test–retest reliability, a comparison of sMuRQoL scores between CI users and NH individuals and an examination of potential evidence of convergent validity and discriminative capacity of sMuRQoL in relation to other tools. This involved the comparison of the questionnaire scores with the Meludia outcomes.ResultsThe sMuRQoL demonstrated a two-dimensional structure. All the dimensions displayed high internal consistency (α = 0.879–0.945) and score stability (ICC = 0.890–0.942). There were significant differences in the Frequency test between NH and CI users (d = 1.19–1.45). There’s evidence of convergent validity between the scores of the Frequency test and the results of Meludia (r = 0.242–0.645). Additionally, the Frequency test demonstrate a good discriminative capacity to identify patients with poorer musical perception.ConclusionsThe sMuRQoL is a reliable questionnaire, with adequate evidence of validity based on internal structure. This study provides an accessible, cost-effective, and quick-to-administer instrument in Spanish, optimizing available healthcare resources and bringing us closer to the patient needs.

A Comparison of Montreal Cognitive Assessment Scores among Individuals with Normal Hearing and Cochlear Implants.

The Montreal Cognitive Assessment (MoCA) is a cognitive screening tool that has 4 of 10 test items heavily dependent on auditory input, potentially leaving hearing-impaired (HI) individuals at a disadvantage. Previous work found that HI individuals scored lower than normal-hearing (NH) individuals on the MoCA, potentially attributed to the degraded auditory signals negatively impacting the ability to commit auditory information to memory. However, there is no research comparing how cochlear implant (CI) recipients perform on the MoCA relative to NH and HI individuals. This study aimed to (1) examine the effect of implementing three different hearing-adjusted scoring methods for a group of age-matched CI recipients and NH individuals, (2) determine if there is a difference between the two groups in overall scores and hearing-adjusted scores, and (3) compare scores across our CI and NH data to the published HI data for all scoring methods. We hypothesized that (1) scores for CI recipients would improve with implementation of the hearing-adjusted scoring methods over the original method, (2) CI recipients would score lower than NH participants for both original and adjusted scoring methods, and (3) the difference in scores between NH and CI listeners for both adjusted and unadjusted scores would be greater than that reported in the literature between NH and HI individuals due to the greater severity of hearing loss and relatively poor spectral resolution of CIs. A total of 94 adults with CIs and 105 adults with NH were initially enrolled. After age-matching the two groups and excluding those who self-identified as NH but failed a hearing screening, a total of 75 CI participants (mean age 61.2 y) and 74 NH participants (mean age 58.8 y) were administered the MoCA. Scores were compared between the NH and CI groups, as well as to published HI data, using the original MoCA scoring method and three alternative scoring methods that excluded various auditory-dependent test items. MoCA scores improved for all groups when two of the three alternative scoring methods were used, with no significant interaction between scoring method and group. Scores for CI recipients were significantly poorer than those for age-matched NH participants for all scoring methods. CI recipients scored better than the published data for HI individuals; however, the HI group was not age matched to the CI and NH groups. MoCA scores are only partly affected by the potentially greater cognitive processing required to interpret degraded auditory signals. Even with the removal of the auditory-dependent items, CI recipients still did not perform as well as the age-matched NH group. Importantly, removing auditory-dependent items significantly and fundamentally alters the test, thereby reducing its sensitivity. This has important limitations for administration and interpretation of the MoCA for people with hearing loss.

Objective and Subjective Assessment of Music Perception and Musical Experiences in Young Cochlear Implant Users.

For many individuals, music has a significant impact on the quality and enjoyability of life. Cochlear implant (CI) users must cope with the constraints that the CI imposes on music perception. Here, we assessed the musical experiences of young CI users and age-matched controls with normal hearing (NH). CI users and NH peers were divided into subgroups according to age: children and adolescents. Participants were tested on their ability to recognize vocal and instrumental music and instruments. A music questionnaire for pediatric populations (MuQPP) was also used. CI users and NH peers identified a similar percentage of vocal music. CI users were significantly worse at recognizing instruments (p < 0.05) and instrumental music (p < 0.05). CI users scored similarly to NH peers on the MuQPP, except for the musical frequency domain, where CI users in the children subgroup scored higher than their NH peers (p = 0.009). For CI users in the children subgroup, the identification of instrumental music was positively correlated with music importance (p = 0.029). Young CI users have significant deficits in some aspects of music perception (instrumental music and instrument identification) but have similar scores to NH peers in terms of interest in music, frequency of music exposure, and importance of music.

Interpersonal distance preferences: an unexplored consequence of hearing loss

BackgroundInterpersonal distance (IPD), which reflects the physical space between people, ensures the regulation of social behavior in interaction as part of nonverbal communication. Our research aims to reveal whether there is a difference in personal distance preference between individuals with hearing loss and normal hearing (NH).MethodsThirty-five adults (26.54 ± 7.05 years) were divided into three groups according to hearing status: hearing aid (HA) users, cochlear implant (CI) users, and NH individuals. The preferred interpersonal distance scale (PIPDS) and a stop distance paradigm were employed for measurements in various environments. Personal space violations were monitored using an electrodermal activity (EDA) wristband.ResultsOur findings showed a significant relationship between preferred interpersonal distance (PID) and hearing loss duration (r = 571; p < .01) and a significant difference in PIDs between CI users and NH individuals (p = .025). There was a correlation between PIPDS results and interpersonal distance preference in two outdoor conditions where the experimenter was male. However, there was no correlation between interpersonal distance and EDA results.ConclusionsFor the CI group, PIPDS results indicated an increased interpersonal distance preference with the severity of hearing loss, possibly to enhance lip-reading cues and conceal visible hearing aids. Understanding these preferences is essential for effective communication and good interpersonal relationships among individuals with hearing loss.

Assessment of High-Variability Speech Recognition in Adult Cochlear Implant Users using PRESTO.

Speech recognition in adult cochlear implant (CI) users is typically assessed using sentence materials with low talker variability. Little is known about the effects of talker variability on speech recognition in adult CI users, the factors underlying individual differences in speech recognition with high talker variability, or how sentence materials with high talker variability could be utilized clinically. To examine the effects of talker variability on sentence recognition in adult CI users, using sentences from the Perceptually Robust English Sentence Test Open-Set (PRESTO), and to examine the relation between working memory capacity and high-variability speech recognition. Postlingually deafened adult CI users and adults with self-reported normal hearing (NH) under CI simulation completed sentence recognition tests that contained varying levels of talker variability, including Hearing in Noise Test (HINT; low-variability), AzBio (moderate-variability), and PRESTO sentences (high-variability). The tasks were completed in both quiet and multitalker babble (MTB). For the adult CI users only, the relation between sentence recognition accuracy and working memory capacity was assessed. Twenty postlingually deafened adult CI users and 35 NH adults under 8-channel acoustic noise-vocoder simulations of CI hearing. In both CI and NH groups, performance decreased as a function of increased talker variability, with the best scores obtained on HINT (low-variability), then AzBio (moderate-variability), followed by PRESTO (high-variability) in quiet. In MTB, performance was significantly lower on PRESTO sentences, compared with HINT and AzBio sentences, which were not significantly different. Working memory capacity in the CI users was related to sentence recognition accuracy across all materials and conditions. Findings from the current study suggest that the increased talker variability in the PRESTO sentence materials has a detrimental effect on speech recognition in both adult CI users and NH listeners under CI simulation, particularly when speech is further degraded by MTB. For adult CI users, working memory capacity contributes to speech recognition abilities. Sentence recognition testing with high-variability, multitalker materials, as in PRESTO, provides robust assessment of speech recognition abilities for research and clinical application, generating a wide range of scores for evaluating individual differences without ceiling effects when compared with conventional low-variability sentences.

Meta-Analysis Exploring the Effects of Music Training in Cochlear Implant Users by Age.

The present study aimed to explore meaningful change in the musical performance of cochlear implant (CI) users according to age after receiving music training compared to the other CI users who did not receive any music training and normal hearing (NH) listeners. Materials and. Article search was conducted from five journal databases. In accordance with PICOS criteria, 29 articles and 15 articles were included for the CI and NH groups, respectively. A total of 44 articles consisting of 407 CI users and 486 NH participants were then analyzed. Using the data gathered from pre- and post-training, meta-analysis was applied by the random-effects model, and then piecewise meta-regression was employed. CI users with music training showed better performance than those without the training across all ages. The curve change in musical performance when training showed that the CI users was similar to the general pattern of NH performance, indicating that the CI users gained benefits from music training and developed perceptual ability, even though it was not as high as the level of NH counterparts. This finding supports the benefits of active engagement with music for both CI users and NH listeners, while noting the important role of music as one of the primary aural rehabilitation approaches.

Age effects on cognitive functions and speech-in-noise processing: An event-related potential study with cochlear-implant users and normal-hearing listeners.

A cochlear implant (CI) can partially restore hearing in individuals with profound sensorineural hearing loss. However, electrical hearing with a CI is limited and highly variable. The current study aimed to better understand the different factors contributing to this variability by examining how age affects cognitive functions and cortical speech processing in CI users. Electroencephalography (EEG) was applied while two groups of CI users (young and elderly; N = 13 each) and normal-hearing (NH) listeners (young and elderly; N = 13 each) performed an auditory sentence categorization task, including semantically correct and incorrect sentences presented either with or without background noise. Event-related potentials (ERPs) representing earlier, sensory-driven processes (N1-P2 complex to sentence onset) and later, cognitive-linguistic integration processes (N400 to semantically correct/incorrect sentence-final words) were compared between the different groups and speech conditions. The results revealed reduced amplitudes and prolonged latencies of auditory ERPs in CI users compared to NH listeners, both at earlier (N1, P2) and later processing stages (N400 effect). In addition to this hearing-group effect, CI users and NH listeners showed a comparable background-noise effect, as indicated by reduced hit rates and reduced (P2) and delayed (N1/P2) ERPs in conditions with background noise. Moreover, we observed an age effect in CI users and NH listeners, with young individuals showing improved specific cognitive functions (working memory capacity, cognitive flexibility and verbal learning/retrieval), reduced latencies (N1/P2), decreased N1 amplitudes and an increased N400 effect when compared to the elderly. In sum, our findings extend previous research by showing that the CI users' speech processing is impaired not only at earlier (sensory) but also at later (semantic integration) processing stages, both in conditions with and without background noise. Using objective ERP measures, our study provides further evidence of strong age effects on cortical speech processing, which can be observed in both the NH listeners and the CI users. We conclude that elderly individuals require more effortful processing at sensory stages of speech processing, which however seems to be at the cost of the limited resources available for the later semantic integration processes.

Recognizing Voices Through a Cochlear Implant: A Systematic Review of Voice Perception, Talker Discrimination, and Talker Identification.

Some cochlear implant (CI) users report having difficulty accessing indexical information in the speech signal, presumably due to limitations in the transmission of fine spectrotemporal cues. The purpose of this review article was to systematically review and evaluate the existing research on talker processing in CI users. Specifically, we reviewed the performance of CI users in three types of talker- and voice-related tasks. We also examined the different factors (such as participant, hearing, and device characteristics) that might influence performance in these specific tasks. We completed a systematic search of the literature with select key words using citation aggregation software to search Google Scholar. We included primary reports that tested (a) talker discrimination, (b) voice perception, and (c) talker identification. Each report must have had at least one group of participants with CIs. Each included study was also evaluated for quality of evidence. The searches resulted in 1,561 references, which were first screened for inclusion and then evaluated in full. Forty-three studies examining talker discrimination, voice perception, and talker identification were included in the final review. Most studies were focused on postlingually deafened and implanted adult CI users, with fewer studies focused on prelingual implant users. In general, CI users performed above chance in these tasks. When there was a difference between groups, CI users performed less accurately than their normal-hearing (NH) peers. A subset of CI users reached the same level of performance as NH participants exposed to noise-vocoded stimuli. Some studies found that CI users and NH participants relied on different cues for talker perception. Within groups of CI users, there is moderate evidence for a bimodal benefit for talker processing, and there are mixed findings about the effects of hearing experience. The current review highlights the challenges faced by CI users in tracking and recognizing voices and how they adapt to it. Although large variability exists, there is evidence that CI users can process indexical information from speech, though with less accuracy than their NH peers. Recent work has described some of the factors that might ease the challenges of talker processing in CI users. We conclude by suggesting some future avenues of research to optimize real-world speech outcomes.

Lexical Access Changes Based on Listener Needs: Real-Time Word Recognition in Continuous Speech in Cochlear Implant Users.

A key challenge in word recognition is the temporary ambiguity created by the fact that speech unfolds over time. In normal hearing (NH) listeners, this temporary ambiguity is resolved through incremental processing and competition among lexical candidates. Post-lingually deafened cochlear implant (CI) users show similar incremental processing and competition but with slight delays. However, even brief delays could lead to drastic changes when compounded across multiple words in a phrase. This study asks whether words presented in non-informative continuous speech (a carrier phrase) are processed differently than in isolation and whether NH listeners and CI users exhibit different effects of a carrier phrase. In a Visual World Paradigm experiment, listeners heard words either in isolation or in non-informative carrier phrases (e.g., "click on the…" ). Listeners selected the picture corresponding to the target word from among four items including the target word (e.g., mustard ), a cohort competitor (e.g., mustache ), a rhyme competitor (e.g., custard ), and an unrelated item (e.g., penguin ). Eye movements were tracked as an index of the relative activation of each lexical candidate as competition unfolds over the course of word recognition. Participants included 21 post-lingually deafened cochlear implant users and 21 NH controls. A replication experiment presented in the Supplemental Digital Content, http://links.lww.com/EANDH/A999 included an additional 22 post-lingually deafened CI users and 18 NH controls. Both CI users and the NH controls were accurate at recognizing the words both in continuous speech and in isolation. The time course of lexical activation (indexed by the fixations) differed substantially between groups. CI users were delayed in fixating the target relative to NH controls. Additionally, CI users showed less competition from cohorts than NH controls (even as previous studies have often report increased competition). However, CI users took longer to suppress the cohort and suppressed it less fully than the NH controls. For both CI users and NH controls, embedding words in carrier phrases led to more immediacy in lexical access as observed by increases in cohort competition relative to when words were presented in isolation. However, CI users were not differentially affected by the carriers. Unlike prior work, CI users appeared to exhibit "wait-and-see" profile, in which lexical access is delayed minimizing early competition. However, CI users simultaneously sustained competitor activation late in the trial, possibly to preserve flexibility. This hybrid profile has not been observed previously. When target words are heard in continuous speech, both CI users and NH controls more heavily weight early information. However, CI users (but not NH listeners) also commit less fully to the target, potentially keeping options open if they need to recover from a misperception. This mix of patterns reflects a lexical system that is extremely flexible and adapts to fit the needs of a listener.

More Than Words: the Relative Roles of Prosody and Semantics in the Perception of Emotions in Spoken Language by Postlingual Cochlear Implant Users.

The processing of emotional speech calls for the perception and integration of semantic and prosodic cues. Although cochlear implants allow for significant auditory improvements, they are limited in the transmission of spectro-temporal fine-structure information that may not support the processing of voice pitch cues. The goal of the current study is to compare the performance of postlingual cochlear implant (CI) users and a matched control group on perception, selective attention, and integration of emotional semantics and prosody. Fifteen CI users and 15 normal hearing (NH) peers (age range, 18-65 years) 1istened to spoken sentences composed of different combinations of four discrete emotions (anger, happiness, sadness, and neutrality) presented in prosodic and semantic channels-T-RES: Test for Rating Emotions in Speech. In three separate tasks, listeners were asked to attend to the sentence as a whole, thus integrating both speech channels (integration), or to focus on one channel only (rating of target emotion) and ignore the other (selective attention). Their task was to rate how much they agreed that the sentence conveyed each of the predefined emotions. In addition, all participants performed standard tests of speech perception. When asked to focus on one channel, semantics or prosody, both groups rated emotions similarly with comparable levels of selective attention. When the task was called for channel integration, group differences were found. CI users appeared to use semantic emotional information more than did their NH peers. CI users assigned higher ratings than did their NH peers to sentences that did not present the target emotion, indicating some degree of confusion. In addition, for CI users, individual differences in speech comprehension over the phone and identification of intonation were significantly related to emotional semantic and prosodic ratings, respectively. CI users and NH controls did not differ in perception of prosodic and semantic emotions and in auditory selective attention. However, when the task called for integration of prosody and semantics, CI users overused the semantic information (as compared with NH). We suggest that as CI users adopt diverse cue weighting strategies with device experience, their weighting of prosody and semantics differs from those used by NH. Finally, CI users may benefit from rehabilitation strategies that strengthen perception of prosodic information to better understand emotional speech.

The timecourse of multisensory speech processing in unilaterally stimulated cochlear implant users revealed by ERPs

A cochlear implant (CI) is an auditory prosthesis which can partially restore the auditory function in patients with severe to profound hearing loss. However, this bionic device provides only limited auditory information, and CI patients may compensate for this limitation by means of a stronger interaction between the auditory and visual system. To better understand the electrophysiological correlates of audiovisual speech perception, the present study used electroencephalography (EEG) and a redundant target paradigm. Postlingually deafened CI users and normal-hearing (NH) listeners were compared in auditory, visual and audiovisual speech conditions. The behavioural results revealed multisensory integration for both groups, as indicated by shortened response times for the audiovisual as compared to the two unisensory conditions. The analysis of the N1 and P2 event-related potentials (ERPs), including topographic and source analyses, confirmed a multisensory effect for both groups and showed a cortical auditory response which was modulated by the simultaneous processing of the visual stimulus. Nevertheless, the CI users in particular revealed a distinct pattern of N1 topography, pointing to a strong visual impact on auditory speech processing. Apart from these condition effects, the results revealed ERP differences between CI users and NH listeners, not only in N1/P2 ERP topographies, but also in the cortical source configuration. When compared to the NH listeners, the CI users showed an additional activation in the visual cortex at N1 latency, which was positively correlated with CI experience, and a delayed auditory-cortex activation with a reversed, rightward functional lateralisation. In sum, our behavioural and ERP findings demonstrate a clear audiovisual benefit for both groups, and a CI-specific alteration in cortical activation at N1 latency when auditory and visual input is combined. These cortical alterations may reflect a compensatory strategy to overcome the limited CI input, which allows the CI users to improve the lip-reading skills and to approximate the behavioural performance of NH listeners in audiovisual speech conditions. Our results are clinically relevant, as they highlight the importance of assessing the CI outcome not only in auditory-only, but also in audiovisual speech conditions.

Distinct multisensory perceptual processes guide enhanced auditory recognition memory in older cochlear implant users

In naturalistic situations, sounds are often perceived in conjunction with matching visual impressions. For example, we see and hear the neighbor’s dog barking in the garden. Still, there is a good chance that we recognize the neighbor’s dog even when we only hear it barking, but do not see it behind the fence. Previous studies with normal-hearing (NH) listeners have shown that the audio-visual presentation of a perceptual object (like an animal) increases the probability to recognize this object later on, even if the repeated presentation of this object occurs in a purely auditory condition. In patients with a cochlear implant (CI), however, the electrical hearing of sounds is impoverished, and the ability to recognize perceptual objects in auditory conditions is significantly limited. It is currently not well understood whether CI users – as NH listeners – show a multisensory facilitation for auditory recognition. The present study used event-related potentials (ERPs) and a continuous recognition paradigm with auditory and audio-visual stimuli to test the prediction that CI users show a benefit from audio-visual perception. Indeed, the congruent audio-visual context resulted in an improved recognition ability of objects in an auditory-only condition, both in the NH listeners and the CI users. The ERPs revealed a group-specific pattern of voltage topographies and correlations between these ERP maps and the auditory recognition ability, indicating a different processing of congruent audio-visual stimuli in CI users when compared to NH listeners. Taken together, our results point to distinct cortical processing of naturalistic audio-visual objects in CI users and NH listeners, which however allows both groups to improve the recognition ability of these objects in a purely auditory context. Our findings are of relevance for future clinical research since audio-visual perception might also improve the auditory rehabilitation after cochlear implantation.

Individual Hearing Outcomes in Cochlear Implant Users Influence Social Engagement and Listening Behavior in Everyday Life.

The goal of this study was to assess the listening behavior and social engagement of cochlear implant (CI) users and normal-hearing (NH) adults in daily life and relate these actions to objective hearing outcomes. Ecological momentary assessments (EMAs) collected using a smartphone app were used to probe patterns of listening behavior in CI users and age-matched NH adults to detect differences in social engagement and listening behavior in daily life. Participants completed very short surveys every 2 hr to provide snapshots of typical, everyday listening and socializing, as well as longer, reflective surveys at the end of the day to assess listening strategies and coping behavior. Speech perception testing, with accompanying ratings of task difficulty, was also performed in a lab setting to uncover possible correlations between objective and subjective listening behavior. Comparisons between speech intelligibility testing and EMA responses showed poorer performing CI users spending more time at home and less time conversing with others than higher performing CI users and their NH peers. Perception of listening difficulty was also very different for CI users and NH listeners, with CI users reporting little difficulty despite poor speech perception performance. However, both CI users and NH listeners spent most of their time in listening environments they considered "not difficult." CI users also reported using several compensatory listening strategies, such as visual cues, whereas NH listeners did not. Overall, the data indicate systematic differences between how individual CI users and NH adults navigate and manipulate listening and social environments in everyday life.

Accuracy and cue use in word segmentation for cochlear-implant listeners and normal-hearing listeners presented vocoded speech.

Cochlear-implant (CI) listeners experience signal degradation, which leads to poorer speech perception than normal-hearing (NH) listeners. In the present study, difficulty with word segmentation, the process of perceptually parsing the speech stream into separate words, is considered as a possible contributor to this decrease in performance. CI listeners were compared to a group of NH listeners (presented with unprocessed speech and eight-channel noise-vocoded speech) in their ability to segment phrases with word segmentation ambiguities (e.g., "an iceman" vs "a nice man"). The results showed that CI listeners and NH listeners were worse at segmenting words when hearing processed speech than NH listeners were when presented with unprocessed speech. When viewed at a broad level, all of the groups used cues to word segmentation in similar ways. Detailed analyses, however, indicated that the two processed speech groups weighted top-down knowledge cues to word boundaries more and weighted acoustic cues to word boundaries less relative to NH listeners presented with unprocessed speech.

Role of semantic context and talker variability in speech perception of cochlear-implant users and normal-hearing listeners.

This study assessed the impact of semantic context and talker variability on speech perception by cochlear-implant (CI) users and compared their overall performance and between-subjects variance with that of normal-hearing (NH) listeners under vocoded conditions. Thirty post-lingually deafened adult CI users were tested, along with 30 age-matched and 30 younger NH listeners, on sentences with and without semantic context, presented in quiet and noise, spoken by four different talkers. Additional measures included working memory, non-verbal intelligence, and spectral-ripple detection and discrimination. Semantic context and between-talker differences influenced speech perception to similar degrees for both CI users and NH listeners. Between-subjects variance for speech perception was greatest in the CI group but remained substantial in both NH groups, despite the uniformly degraded stimuli in these two groups. Spectral-ripple detection and discrimination thresholds in CI users were significantly correlated with speech perception, but a single set of vocoder parameters for NH listeners was not able to capture average CI performance in both speech and spectral-ripple tasks. The lack of difference in the use of semantic context between CI users and NH listeners suggests no overall differences in listening strategy between the groups, when the stimuli are similarly degraded.

Speech Recognition in Noise in Single-Sided Deaf Cochlear Implant Children on Using Adaptive Digital Microphone Technology.

Previous research demonstrated benefits of adaptive digital microphone technologies (ADMTs) in adults with single-sided deafness (SSD) having a cochlear implant (CI). Children with SSD are especially affected by background noise because of their noise exposure in kindergarten and school. This article aims to evaluate possible effects of ADMT on speech recognition in background noise in children with SSD who use a CI. Ten children between 5 and 11 years of age were included. Speech recognition in noise was assessed for one frontal distant and two lateral speakers. The speech stimulus was presented at a speech level of 65 dB(A) and noise at a level of 55 dB(A). For the presentation condition with one frontal speaker, four listening conditions were assessed: (1) normal-hearing (NH) ear and CI turned off; (2) NH ear and CI; (3) NH ear and CI with ADMT; and (4) NH ear with ADMT and CI. Listening conditions (2) to (4) were also tested for each lateral speaker. The frontal speaker was positioned directly in front of the participant, whereas the lateral speakers were positioned at angles of 90 degrees and -90 degrees to the participant's head. Children with SSD who use a CI significantly benefit from the application of ADMT in speech recognition in noise for frontal distant and for lateral speakers. Speech recognition improved significantly with ADMT at the CI and the NH ears. Application of ADMT significantly improves speech recognition in noise in children with SSD who use a CI and can therefore be highly recommended. The decision of whether to apply ADMT at the CI NH ear or bilaterally should be made for each child individually.

Cognitive factors contribute to speech perception in cochlear-implant users and age-matched normal-hearing listeners under vocoded conditions.

This study examined the contribution of perceptual and cognitive factors to speech-perception abilities in cochlear-implant (CI) users. Thirty CI users were tested on word intelligibility in sentences with and without semantic context, presented in quiet and in noise. Performance was compared with measures of spectral-ripple detection and discrimination, thought to reflect peripheral processing, as well as with cognitive measures of working memory and non-verbal intelligence. Thirty age-matched and thirty younger normal-hearing (NH) adults also participated, listening via tone-excited vocoders, adjusted to produce mean performance for speech in noise comparable to that of the CI group. Results suggest that CI users may rely more heavily on semantic context than younger or older NH listeners, and that non-auditory working memory explains significant variance in the CI and age-matched NH groups. Between-subject variability in spectral-ripple detection thresholds was similar across groups, despite the spectral resolution for all NH listeners being limited by the same vocoder, whereas speech perception scores were more variable between CI users than between NH listeners. The results highlight the potential importance of central factors in explaining individual differences in CI users and question the extent to which standard measures of spectral resolution in CIs reflect purely peripheral processing.

A Randomized Controlled Crossover Study of the Impact of Online Music Training on Pitch and Timbre Perception in Cochlear Implant Users.

Cochlear implant (CI) biomechanical constraints result in impoverished spectral cues and poor frequency resolution, making it difficult for users to perceive pitch and timbre. There is emerging evidence that music training may improve CI-mediated music perception; however, much of the existing studies involve time-intensive and less readily accessible in-person music training paradigms, without rigorous experimental control paradigms. Online resources for auditory rehabilitation remain an untapped potential resource for CI users. Furthermore, establishing immediate value from an acute music training program may encourage CI users to adhere to post-implantation rehabilitation exercises. In this study, we evaluated the impact of an acute online music training program on pitch discrimination and timbre identification. Via a randomized controlled crossover study design, 20 CI users and 21 normal hearing (NH) adults were assigned to one of two arms. Arm-A underwent 1month of online self-paced music training (intervention) followed by 1month of audiobook listening (control). Arm-B underwent 1month of audiobook listening followed by 1month of music training. Pitch and timbre sensitivity scores were taken across three visits: (1) baseline, (2) after 1month of intervention, and (3) after 1month of control. We found that performance improved in pitch discrimination among CI users and NH listeners, with both online music training and audiobook listening. Music training, however, provided slightly greater benefit for instrument identification than audiobook listening. For both tasks, this improvement appears to be related to both fast stimulus learning as well as procedural learning. In conclusion, auditory training (with either acute participation in an online music training program or audiobook listening) may improve performance on untrained tasks of pitch discrimination and timbre identification. These findings demonstrate a potential role for music training in perceptual auditory appraisal of complex stimuli. Furthermore, this study highlights the importance and the need for more tightly controlled training studies in order to accurately evaluate the impact of rehabilitation training protocols on auditory processing.

The effect of delayed auditory feedback (DAF) and frequency altered feedback (FAF) on speech production: cochlear implanted versus normal hearing individuals

ABSTRACTNormal auditory feedback contributes to moment-to-moment control of speech production. Effects of auditory feedback’s absence on hearing-impaired individuals are widely documented, but auditory perturbation has not been investigated. Our objective was to evaluate the effect of delayed auditory feedback (DAF) and frequency altered feedback (FAF) on speech production among prelingual cochlear implant (CI) users and normal hearing (NH) individuals, to evaluate CI users’ reliance on auditory feedback. Twenty young adults (10 CI, 10 NH), without developmental and cognitive impairments, participated in the study. Under variable auditory feedback conditions, speech production (spontaneous or reading aloud) was measured using speech rate, percentage of interruptions, fundamental frequency (F0), and relative intensity. Results showed that (1) both DAF and FAF caused slower speech rates and more interruptions while reading aloud, with DAF having larger effect; (2) altered feedback produced no differences between groups, except an increase in F0 for CI users during DAF; and (3) CI users’ ability to understand speech via phone and without lip-reading was positively correlated with performance under DAF. These findings suggest that auditory perturbation similarly affects speech production among prelingual CI users and NH individuals, indicating CI users depend on auditory feedback to the same degree as normal hearing individuals.

Effect of Compression on Musical Sound Quality in Cochlear Implant Users.

Cochlear implant (CI) users frequently report poor sound quality while listening to music, although the specific parameters responsible for this loss of sound quality remain poorly understood. Audio compression, which reduces the dynamic range (DR) for a given sound, is a ubiquitous component of signal processing used by both CI and hearing aid technology. However, the relative impact of compression for acoustic and electric hearing on music perception has not been well studied, an important consideration especially given that most compression algorithms in CIs were developed to optimize speech perception. The authors hypothesized that normal-hearing (NH) listeners would detect increased levels of compression more easily than CI users, but that both groups would perceive a loss of sound quality with increasing compression levels. The present study utilizes the Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor to evaluate the listener sensitivity to increasing levels of compression applied to music stimuli. The Cochlear Implant-MUltiple Stimulus with Hidden Reference and Anchor is a tool used to assess relative changes in the perceived sound quality of music across increasingly degraded listening conditions, in both CI and NH subjects. In this study, the authors applied multiple iterations of an aggressive compression algorithm to the music clips using Adobe Audition. The test conditions included 1, 3, 5, and 20 iterations sound tokens, with the 20-iteration samples serving as the Anchor stimuli. The compressed excerpts were 5 sec in length, with five clips for each of the five common musical genres (i.e., Classical, Jazz, Country, Rock, and Hip-Hop). Subjects were also presented with a Reference excerpt, which was the original music clip without any additional compression applied. CI recipients (n = 7, 11 ears) and NH listeners (n = 10) were asked to rate the sound quality of additionally compressed music as compared to the Reference. Although both NH and CI groups could detect sound quality differences as a function of compression level, the discriminatory ability of the CI group was blunted compared to the NH group. The CI group had less variability in their responses and overall demonstrated reduced sensitivity to deterioration caused by excessive levels of compression. On average, the CI group rated the Anchor condition as only "Slightly worse" than the Reference. The music clips that were most affected by the compression were from Jazz and Hip-Hop genres and less so for Rock and Country clips. Corollary to this was a small but statistically significant impact of DR of the music clips on sound quality ratings, with narrower DR showing an association with poorer ratings. These results indicate that CI users exhibit less sensitivity to sound quality changes in music attributable to high levels of compression. These findings may account for another contributing factor to the generally poor music perception observed in CI users, particularly when listening to commercially recorded music.