Safety and Early Outcomes of Cochlear Implantation of Nucleus Devices in Infants: A Multi-Centre Study.

This multi-center study examined the safety and effectiveness of cochlear implantation of children between 9 and 11 months of age. The intended impact was to support practice regarding candidacy assessment and prognostic counseling of pediatric cochlear implant candidates. Data in the clinical chart of children implanted at 9-11 months of age with Cochlear Ltd devices at five cochlear implant centers in the United States and Canada were included in analyses. The study included data from two cohorts implanted with one or two Nucleus devices during the periods of January 1, 2012-December 31, 2017 (Cohort 1, n = 83) or between January 1, 2018 and May 15, 2020 (Cohort 2, n = 50). Major adverse events (requiring another procedure/hospitalization) and minor adverse events (managed with medication alone or underwent an expected course of treatment that did not require surgery or hospitalization) out to 2 years post-implant were monitored and outcomes measured by audiometric thresholds and parent-reports on the IT-MAIS and LittlEARS questionnaires were collected. Results revealed 60 adverse events in 41 children and 227 ears implanted (26%) of which 14 major events occurred in 11 children; all were transitory and resolved. Improved hearing with cochlear implant use was shown in all outcome measures. Findings reveal that the procedure is safe for infants and that they show clear benefits of cochlear implantation including increased audibility and hearing development.

Cross-modal plasticity in children with cochlear implant: converging evidence from EEG and functional near-infrared spectroscopy.

Over the first years of life, the brain undergoes substantial organization in response to environmental stimulation. In a silent world, it may promote vision by (i) recruiting resources from the auditory cortex and (ii) making the visual cortex more efficient. It is unclear when such changes occur and how adaptive they are, questions that children with cochlear implants can help address. Here, we examined 7-18 years old children: 50 had cochlear implants, with delayed or age-appropriate language abilities, and 25 had typical hearing and language. High-density electroencephalography and functional near-infrared spectroscopy were used to evaluate cortical responses to a low-level visual task. Evidence for a 'weaker visual cortex response' and 'less synchronized or less inhibitory activity of auditory association areas' in the implanted children with language delays suggests that cross-modal reorganization can be maladaptive and does not necessarily strengthen the dominant visual sense.

Motor Processing in Children With Cochlear Implants as Assessed by Functional Near-Infrared Spectroscopy.

Auditory-motor and visual-motor networks are often coupled in daily activities, such as when listening to music and dancing; but these networks are known to be highly malleable as a function of sensory input. Thus, congenital deafness may modify neural activities within the connections between the motor, auditory, and visual cortices. Here, we investigated whether the cortical responses of children with cochlear implants (CI) to a simple and repetitive motor task would differ from that of children with typical hearing (TH) and we sought to understand whether this response related to their language development. Participants were 75 school-aged children, including 50 with CI (with varying language abilities) and 25 controls with TH. We used functional near-infrared spectroscopy (fNIRS) to record cortical responses over the whole brain, as children squeezed the back triggers of a joystick that vibrated or not with the squeeze. Motor cortex activity was reflected by an increase in oxygenated hemoglobin concentration (HbO) and a decrease in deoxygenated hemoglobin concentration (HbR) in all children, irrespective of their hearing status. Unexpectedly, the visual cortex (supposedly an irrelevant region) was deactivated in this task, particularly for children with CI who had good language skills when compared to those with CI who had language delays. Presence or absence of vibrotactile feedback made no difference in cortical activation. These findings support the potential of fNIRS to examine cognitive functions related to language in children with CI.

Audiovisual integration in children with cochlear implants revealed through EEG and fNIRS.

Sensory deprivation can offset the balance of audio versus visual information in multimodal processing. Such a phenomenon could persist for children born deaf, even after they receive cochlear implants (CIs), and could potentially explain why one modality is given priority over the other. Here, we recorded cortical responses to a single speaker uttering two syllables, presented in audio-only (A), visual-only (V), and audio-visual (AV) modes. Electroencephalography (EEG) and functional near-infrared spectroscopy (fNIRS) were successively recorded in seventy-five school-aged children. Twenty-five were children with normal hearing (NH) and fifty wore CIs, among whom 26 had relatively high language abilities (HL) comparable to those of NH children, while 24 others had low language abilities (LL). In EEG data, visual-evoked potentials were captured in occipital regions, in response to V and AV stimuli, and they were accentuated in the HL group compared to the LL group (the NH group being intermediate). Close to the vertex, auditory-evoked potentials were captured in response to A and AV stimuli and reflected a differential treatment of the two syllables but only in the NH group. None of the EEG metrics revealed any interaction between group and modality. In fNIRS data, each modality induced a corresponding activity in visual or auditory regions, but no group difference was observed in A, V, or AV stimulation. The present study did not reveal any sign of abnormal AV integration in children with CI. An efficient multimodal integrative network (at least for rudimentary speech materials) is clearly not a sufficient condition to exhibit good language and literacy.

Dynamic networks differentiate the language ability of children with cochlear implants.

Background: Cochlear implantation (CI) in prelingually deafened children has been shown to be an effective intervention for developing language and reading skill. However, there is a substantial proportion of the children receiving CI who struggle with language and reading. The current study-one of the first to implement electrical source imaging in CI population was designed to identify the neural underpinnings in two groups of CI children with good and poor language and reading skill. Methods: Data using high density electroencephalography (EEG) under a resting state condition was obtained from 75 children, 50 with CIs having good (HL) or poor language skills (LL) and 25 normal hearing (NH) children. We identified coherent sources using dynamic imaging of coherent sources (DICS) and their effective connectivity computing time-frequency causality estimation based on temporal partial directed coherence (TPDC) in the two CI groups compared to a cohort of age and gender matched NH children. Findings: Sources with higher coherence amplitude were observed in three frequency bands (alpha, beta and gamma) for the CI groups when compared to normal hearing children. The two groups of CI children with good (HL) and poor (LL) language ability exhibited not only different cortical and subcortical source profiles but also distinct effective connectivity between them. Additionally, a support vector machine (SVM) algorithm using these sources and their connectivity patterns for each CI group across the three frequency bands was able to predict the language and reading scores with high accuracy. Interpretation: Increased coherence in the CI groups suggest overall that the oscillatory activity in some brain areas become more strongly coupled compared to the NH group. Moreover, the different sources and their connectivity patterns and their association to language and reading skill in both groups, suggest a compensatory adaptation that either facilitated or impeded language and reading development. The neural differences in the two groups of CI children may reflect potential biomarkers for predicting outcome success in CI children.

Auditory evoked response to an oddball paradigm in children wearing cochlear implants.

OBJECTIVE: Although children with cochlear implants (CI) achieve remarkable success with their device, considerable variability remains in individual outcomes. Here, we explored whether auditory evoked potentials recorded during an oddball paradigm could provide useful markers of auditory processing in this pediatric population. METHODS: High-density electroencephalography (EEG) was recorded in 75 children listening to standard and odd noise stimuli: 25 had normal hearing (NH) and 50 wore a CI, divided between high language (HL) and low language (LL) abilities. Three metrics were extracted: the first negative and second positive components of the standard waveform (N1-P2 complex) close to the vertex, the mismatch negativity (MMN) around Fz and the late positive component (P3) around Pz of the difference waveform. RESULTS: While children with CIs generally exhibited a well-formed N1-P2 complex, those with language delays typically lacked reliable MMN and P3 components. But many children with CIs with age-appropriate skills showed MMN and P3 responses similar to those of NH children. Moreover, larger and earlier P3 (but not MMN) was linked to better literacy skills. CONCLUSIONS: Auditory evoked responses differentiated children with CIs based on their good or poor skills with language and literacy. SIGNIFICANCE: This short paradigm could eventually serve as a clinical tool for tracking the developmental outcomes of implanted children.

Remote Microphone Systems for Cochlear Implant Recipients in Small Group Settings.

PURPOSE: Cochlear implant (CI) recipients often experience speech recognition difficulty in noise in small group settings with multiple talkers. In traditional remote microphones systems, one talker wears a remote microphone that wirelessly delivers speech to the CI processor. This system will not transmit signals from multiple talkers in a small group. However, remote microphone systems with multiple microphones allowing for adaptive beamforming may be beneficial for small group situations with multiple talkers. Specifically, a remote microphone with an adaptive multiple-microphone beamformer may be placed in the center of the small group, and the beam (i.e., polar lobe) may be automatically steered toward the direction associated with the most favorable speech-to-noise ratio. The signal from the remote microphone can then be wirelessly delivered to the CI sound processor. Alternately, each of the talkers in a small group may use a remote microphone that is part of a multi-talker network that wirelessly delivers the remote microphone signal to the CI sound processor. The purpose of this study was to compare the potential benefit of an adaptive multiple-microphone beamformer remote microphone system and a multi-talker network remote microphone system. METHOD: Twenty recipients, ages 12 to 84 years, with Advanced Bionics CIs completed sentence-recognition-in-noise tasks while seated at a desk surrounded by three loudspeakers at 0, 90, and 270 degrees. These speakers randomly presented the target speech while competing noise was presented from four loudspeakers located in the corners of the room. Testing was completed in three conditions: 1) CI alone, 2) Remote microphone system with an adaptive multiple-microphone beamformer, and 3) and a multi-talker network remote microphone system each with five different signal levels (15 total conditions). RESULTS: Significant differences were found across all signal levels and technology conditions. Relative to the CI alone, sentence recognition improvements ranged from 14-23 percentage points with the adaptive multiple-microphone beamformer and 27-47 percentage points with the multi-talker network with superior performance for the latter remote microphone system. CONCLUSIONS: Both remote microphone systems significantly improved speech recognition in noise of CI recipients when listening in small group settings, but the multi-talker network provided superior performance.

Evaluation of Potential Benefits and Limitations of Noise-Management Technologies for Children with Hearing Aids.

BACKGROUND: Children with hearing loss frequently experience difficulty understanding speech in the presence of noise. Although remote microphone systems are likely to be the most effective solution to improve speech recognition in noise, the focus of this study centers on the evaluation of hearing aid noise management technologies including directional microphones, adaptive noise reduction (ANR), and frequency-gain shaping. These technologies can improve children's speech recognition, listening comfort, and/or sound quality in noise. However, individual contributions of these technologies as well as the effect of hearing aid microphone mode on localization abilities in children is unknown. PURPOSE: The objectives of this study were to (1) compare children's speech recognition and subjective perceptions across five hearing aid noise management technology conditions and (2) compare localization abilities across three hearing aid microphone modes. RESEARCH DESIGN: A single-group, repeated measures design was used to evaluate performance differences and subjective ratings. STUDY SAMPLE: Fourteen children with mild to moderately severe hearing loss. DATA COLLECTION AND ANALYSIS: Children's sentence recognition, listening comfort, sound quality, and localization were assessed in a room with an eight-loudspeaker array. RESULTS AND CONCLUSION: The use of adaptive directional microphone technology improves children's speech recognition in noise when the signal of interest arrives from the front and is spatially separated from the competing noise. In contrast, the use of adaptive directional microphone technology may result in a decrease in speech recognition in noise when the signal of interest arrives from behind. The use of a microphone mode that mimics the natural directivity of the unaided auricle provides a slight improvement in speech recognition in noise compared with omnidirectional use with limited decrement in speech recognition in noise when the signal of interest arrives from behind. The use of ANR and frequency-gain shaping provide no change in children's speech recognition in noise. The use of adaptive directional microphone technology, ANR, and frequency-gain shaping improve children's listening comfort, perceived ability to understand speech in noise, and overall listening experience. Children prefer to use each of these noise management technologies regardless of whether the signal of interest arrives from the front or from behind. The use of adaptive directional microphone technology does not result in a decrease in children's localization abilities when compared with the omnidirectional condition. The best localization performance occurred with use of the microphone mode that mimicked the directivity of the unaided auricle.

American Cochlear Implant Alliance Task Force Guidelines for Clinical Assessment and Management of Cochlear Implantation in Children With Single-Sided Deafness.

More children with single-sided deafness (SSD) are receiving cochlear implants (CIs) due to the expansion of CI indications. This unique group of pediatric patients has different needs than the typical recipient with bilateral deafness and requires special consideration and care. The goal of cochlear implantation in these children is to provide bilateral input to encourage the development of binaural hearing. Considerations for candidacy and follow-up care should reflect and measure these goals. The purpose of this document is to review the current evidence and provide guidance for CI candidacy, evaluation, and management in children with SSD.

Low-Level Speech Recognition of Children with Hearing Aids.

BACKGROUND: For children with hearing loss, the primary goal of hearing aids is to provide improved access to the auditory environment within the limits of hearing aid technology and the child's auditory abilities. However, there are limited data examining aided speech recognition at very low (40 decibels A [dBA]) and low (50 dBA) presentation levels. PURPOSE: Due to the paucity of studies exploring aided speech recognition at low presentation levels for children with hearing loss, the present study aimed to (1) compare aided speech recognition at different presentation levels between groups of children with "normal" hearing and hearing loss, (2) explore the effects of aided pure tone average and aided Speech Intelligibility Index (SII) on aided speech recognition at low presentation levels for children with hearing loss ranging in degree from mild to severe, and (3) evaluate the effect of increasing low-level gain on aided speech recognition of children with hearing loss. RESEARCH DESIGN: In phase 1 of this study, a two-group, repeated-measures design was used to evaluate differences in speech recognition. In phase 2 of this study, a single-group, repeated-measures design was used to evaluate the potential benefit of additional low-level hearing aid gain for low-level aided speech recognition of children with hearing loss. STUDY SAMPLE: The first phase of the study included 27 school-age children with mild to severe sensorineural hearing loss and 12 school-age children with "normal" hearing. The second phase included eight children with mild to moderate sensorineural hearing loss. INTERVENTION: Prior to the study, children with hearing loss were fitted binaurally with digital hearing aids. Children in the second phase were fitted binaurally with digital study hearing aids and completed a trial period with two different gain settings: (1) gain required to match hearing aid output to prescriptive targets (i.e., primary program), and (2) a 6-dB increase in overall gain for low-level inputs relative to the primary program. In both phases of this study, real-ear verification measures were completed to ensure the hearing aid output matched prescriptive targets. DATA COLLECTION AND ANALYSIS: Phase 1 included monosyllabic word recognition and syllable-final plural recognition at three presentation levels (40, 50, and 60 dBA). Phase 2 compared speech recognition performance for the same test measures and presentation levels with two differing gain prescriptions. CONCLUSION: In phase 1 of the study, aided speech recognition was significantly poorer in children with hearing loss at all presentation levels. Higher aided SII in the better ear (55 dB sound pressure level input) was associated with higher Consonant-Nucleus-Consonant word recognition at a 40 dBA presentation level. In phase 2, increasing the hearing aid gain for low-level inputs provided a significant improvement in syllable-final plural recognition at very low-level inputs and resulted in a nonsignificant trend toward better monosyllabic word recognition at very low presentation levels. Additional research is needed to document the speech recognition difficulties children with hearing aids may experience with low-level speech in the real world as well as the potential benefit or detriment of providing additional low-level hearing aid gain.

Factors Associated with Speech-Recognition Performance in School-Aged Children with Cochlear Implants and Early Auditory-Verbal Intervention.

BACKGROUND: Considerable variability exists in the speech recognition abilities achieved by children with cochlear implants (CIs) due to varying demographic and performance variables including language abilities. PURPOSE: This article examines the factors associated with speech recognition performance of school-aged children with CIs who were grouped by language ability. RESEARCH DESIGN: This is a single-center cross-sectional study with repeated measures for subjects across two language groups. STUDY SAMPLE: Participants included two groups of school-aged children, ages 7 to 17 years, who received unilateral or bilateral CIs by 4 years of age. The High Language group (N = 26) had age-appropriate spoken-language abilities, and the Low Language group (N = 24) had delays in their spoken-language abilities. DATA COLLECTION AND ANALYSIS: Group comparisons were conducted to examine the impact of demographic characteristics on word recognition in quiet and sentence recognition in quiet and noise. RESULTS: Speech recognition in quiet and noise was significantly poorer in the Low Language compared with the High Language group. Greater hours of implant use and better adherence to auditory-verbal (AV) therapy appointments were associated with higher speech recognition in quiet and noise. CONCLUSION: To ensure maximal speech recognition in children with low-language outcomes, professionals should develop strategies to ensure that families support full-time CI use and have the means to consistently attend AV appointments.

Benefits of Bilateral Hearing on the Telephone for Cochlear Implant Recipients.

BACKGROUND: Cochlear implant (CI) recipients frequently experience difficulty understanding speech over the telephone and rely on hearing assistive technology (HAT) to improve performance. Bilateral inter-processor audio streaming technology using nearfield magnetic induction is an advanced technology incorporated within a hearing aid or CI processor that can deliver telephone audio signals captured at one sound processor to the sound processor at the opposite ear. To date, limited data exist examining the efficacy of this technology in CI users to improve speech understanding on the telephone. PURPOSE: The primary objective of this study was to examine telephone speech recognition outcomes in bilateral CI recipients in a bilateral inter-processor audio streaming condition (DuoPhone) compared with a monaural condition (i.e., telephone listening with one sound processor) in quiet and in background noise. Outcomes in the monaural and bilateral conditions using either a telecoil or T-Mic2 technology were also assessed. The secondary aim was to examine how deactivating microphone input in the contralateral processor in the bilateral wireless streaming conditions, and thereby modifying the signal-to-noise ratio, affected speech recognition in noise. RESEARCH DESIGN: A repeated-measures design was used to evaluate speech recognition performance in quiet and competing noise with the telephone signal transmitted acoustically or via the telecoil to the ipsilateral sound processor microphone in monaural and bilateral wireless streaming listening conditions. STUDY SAMPLE: Nine bilateral CI users with Advanced Bionics HiRes 90K and/or CII devices were included in the study. DATA COLLECTION AND ANALYSIS: The effects of phone input (monaural [DuoPhone Off] vs. bilateral [DuoPhone on]) and processor input (T-Mic2 vs. telecoil) on word recognition in quiet and noise were assessed using separate repeated-measures analysis of variance. Effect of the contralateral device mic deactivation on speech recognition outcomes for the T-Mic2 DuoPhone conditions was assessed using paired Student's t-tests. RESULTS: Telephone speech recognition was significantly better in the bilateral inter-processor streaming conditions relative to the monaural conditions in both quiet and noise. Speech recognition outcomes were similar in quiet and noise when using the T-Mic2 and telecoil in the monaural and bilateral conditions. For the acoustic DuoPhone conditions using the T-Mic2, speech recognition in noise was significantly better when the microphone of the contralateral processor was disabled. CONCLUSION: Inter-processor audio streaming allows for bilateral listening on the telephone and produces better speech recognition in quiet and in noise compared with monaural listening conditions for adult CI recipients.

Specialized and shared functions of diguanylate cyclases and phosphodiesterases in Streptomyces development.

The second messenger bis-3,5-cyclic di-guanosine monophosphate (c-di-GMP) determines when Streptomyces initiate sporulation. c-di-GMP signals are integrated into the genetic differentiation network by the regulator BldD and the sigma factor σWhiG . However, functions of the development-specific diguanylate cyclases (DGCs) CdgB and CdgC, and the c-di-GMP phosphodiesterases (PDEs) RmdA and RmdB, are poorly understood. Here, we provide biochemical evidence that the GGDEF-EAL domain protein RmdB from S. venezuelae is a monofunctional PDE that hydrolyzes c-di-GMP to 5'pGpG. Despite having an equivalent GGDEF-EAL domain arrangement, RmdA cleaves c-di-GMP to GMP and exhibits residual DGC activity. We show that an intact EAL motif is crucial for the in vivo function of both enzymes since strains expressing protein variants with an AAA motif instead of EAL are delayed in development, similar to null mutants. Transcriptome analysis of ∆cdgB, ∆cdgC, ∆rmdA, and ∆rmdB strains revealed that the c-di-GMP specified by these enzymes has a global regulatory role, with about 20% of all S. venezuelae genes being differentially expressed in the cdgC mutant. Our data suggest that the major c-di-GMP-controlled targets determining the timing and mode of sporulation are genes involved in cell division and the production of the hydrophobic sheath that covers Streptomyces aerial hyphae and spores.

Expression Patterns, Genomic Conservation and Input Into Developmental Regulation of the GGDEF/EAL/HD-GYP Domain Proteins in Streptomyces.

To proliferate, antibiotic-producing Streptomyces undergo a complex developmental transition from vegetative growth to the production of aerial hyphae and spores. This morphological switch is controlled by the signaling molecule cyclic bis-(3',5') di-guanosine-mono-phosphate (c-di-GMP) that binds to the master developmental regulator, BldD, leading to repression of key sporulation genes during vegetative growth. However, a systematical analysis of all the GGDEF/EAL/HD-GYP proteins that control c-di-GMP levels in Streptomyces is still lacking. Here, we have FLAG-tagged all 10 c-di-GMP turnover proteins in Streptomyces venezuelae and characterized their expression patterns throughout the life cycle, revealing that the diguanylate cyclase (DGC) CdgB and the phosphodiesterase (PDE) RmdB are the most abundant GGDEF/EAL proteins. Moreover, we have deleted all the genes coding for c-di-GMP turnover enzymes individually and analyzed morphogenesis of the mutants in macrocolonies. We show that the composite GGDEF-EAL protein CdgC is an active DGC and that deletion of the DGCs cdgB and cdgC enhance sporulation whereas deletion of the PDEs rmdA and rmdB delay development in S. venezuelae. By comparing the pan genome of 93 fully sequenced Streptomyces species we show that the DGCs CdgA, CdgB, and CdgC, and the PDE RmdB represent the most conserved c-di-GMP-signaling proteins in the genus Streptomyces.

Colloids for Catalysts: A Concept for the Preparation of Superior Catalysts of Industrial Relevance.

Compared to conventional preparation methods for supported heterogeneous catalysts, the use of colloidal nanoparticles (NPs) allows for a precise control over size, size distribution, and distribution/location of the NPs on the support. However, common colloidal syntheses have restrictions that limit their applicability for industrial catalyst preparation. We present a simple, surfactant-free, and scalable preparation method for colloidal NPs to overcome these restrictions. We demonstrate how precious-metal NPs are prepared in alkaline methanol, how the particle size can be tuned, and how supported catalysts are obtained. The potential of these colloids in the preparation of improved catalysts is demonstrated by two examples from heterogeneous catalysis and electrocatalysis.

The complex co-translational processing of glycoprotein GP5 of type 1 porcine reproductive and respiratory syndrome virus.

GP5 and M, the major membrane proteins of porcine reproductive and respiratory syndrome virus (PRRSV), are the driving force for virus budding and a target for antibodies. We studied co-translational processing of GP5 from an European PRRSV-1 strain. Using mass spectrometry, we show that in virus particles of a Lelystad variant, the signal peptide of GP5 was absent due to cleavage between glycine-34 and asparagine-35. This cleavage site removes an epitope for a neutralizing monoclonal antibody, but leaves intact another epitope recognized by neutralizing pig sera. Upon ectopic expression of this GP5 in cells, signal peptide cleavage was however inefficient. Complete cleavage occurred when cysteine-24 was changed to proline or an unused glycosylation site involving asparagine-35 was mutated. Insertion of proline at position 24 also caused carbohydrate attachment to asparagine-35. Glycosylation sites introduced downstream of residue 35 were used, but did not inhibit signal peptide processing. Co-expression of the M protein rescued this processing defect in GP5, suggesting a novel function of M towards GP5. We speculate that a complex interplay of the co-translational modifications of GP5 affect the N-terminal structure of the mature proteins and hence its antigenicity.

Potential Benefits of an Integrated Electric-Acoustic Sound Processor with Children: A Preliminary Report.

BACKGROUND: A number of published studies have demonstrated the benefits of electric-acoustic stimulation (EAS) over conventional electric stimulation for adults with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. These benefits potentially include better speech recognition in quiet and in noise, better localization, improvements in sound quality, better music appreciation and aptitude, and better pitch recognition. There is, however, a paucity of published reports describing the potential benefits and limitations of EAS for children with functional low-frequency acoustic hearing and severe-to-profound high-frequency hearing loss. PURPOSE: The objective of this study was to explore the potential benefits of EAS for children. RESEARCH DESIGN: A repeated measures design was used to evaluate performance differences obtained with EAS stimulation versus acoustic- and electric-only stimulation. STUDY SAMPLE: Seven users of Cochlear Nucleus Hybrid, Nucleus 24 Freedom, CI512, and CI422 implants were included in the study. DATA COLLECTION AND ANALYSIS: Sentence recognition (assayed using the pediatric version of the AzBio sentence recognition test) was evaluated in quiet and at three fixed signal-to-noise ratios (SNR) (0, +5, and +10 dB). Functional hearing performance was also evaluated with the use of questionnaires, including the comparative version of the Speech, Spatial, and Qualities, the Listening Inventory for Education Revised, and the Children's Home Inventory for Listening Difficulties. RESULTS: Speech recognition in noise was typically better with EAS compared to participants' performance with acoustic- and electric-only stimulation, particularly when evaluated at the less favorable SNR. Additionally, in real-world situations, children generally preferred to use EAS compared to electric-only stimulation. Also, the participants' classroom teachers observed better hearing performance in the classroom with the use of EAS. CONCLUSIONS: Use of EAS provided better speech recognition in quiet and in noise when compared to performance obtained with use of acoustic- and electric-only stimulation, and children responded favorably to the use of EAS implemented in an integrated sound processor for real-world use.

Benefits of Adaptive Signal Processing in a Commercially Available Cochlear Implant Sound Processor.

OBJECTIVE: Cochlear implant recipients often experience difficulty understanding speech in noise. The primary objective of this study was to evaluate the potential improvement in speech recognition in noise provided by an adaptive, commercially available sound processor that performs acoustic scene classification and automatically adjusts input signal processing to maximize performance in noise. RESEARCH DESIGN: Within-subjects, repeated-measures design. SETTING: This multicenter study was conducted across five sites in the U.S.A. and Australia. PATIENTS: Ninety-three adults and children with Nucleus Freedom, CI422, and CI512 cochlear implants. INTERVENTION: Subjects (previous users of the Nucleus 5 sound processor) were fitted with the Nucleus 6 sound processor. Performance was assessed while these subjects used each sound processor in the manufacturer's recommended default program (standard directionality, ASC + ADRO for the Nucleus 5 processor and ASC + ADRO and SNR-NR with SCAN for the Nucleus 6 sound processor). The subjects were also evaluated with the Nucleus 6 with standard directionality, ASC + ADRO and SNR-NR enabled but SCAN disabled. MAIN OUTCOME MEASURES: Speech recognition in noise was assessed with AzBio sentences. RESULTS: Sentence recognition in noise was significantly better with the Nucleus 6 sound processor when used with the default input processing (ASC + ADRO, SNR-NR, and SCAN) compared to performance with the Nucleus 5 sound processor and default input processing (standard directionality, ASC + ADRO). Specifically, use of the Nucleus 6 at default settings resulted in a mean improvement in sentence recognition in noise of 27 percentage points relative to performance with the Nucleus 5 sound processor. Use of the Nucleus 6 sound processor using standard directionality, ASC + ADRO and SNR-NR (SCAN disabled) resulted in a mean improvement of 9 percentage points in sentence recognition in noise compared to performance with the Nucleus 5. CONCLUSION: The results of this study suggest that the Nucleus 6 sound processor with acoustic scene classification, automatic, adaptive directionality, and speech enhancement in noise processing provides significantly better speech recognition in noise when compared to performance with the Nucleus 5 processor.

Evaluation of wideband frequency responses and non-linear frequency compression for children with mild to moderate high-frequency hearing loss.

OBJECTIVE: To evaluate wideband amplification and non-linear frequency compression (NLFC) as a means to improve speech recognition for children with mild/moderate hearing loss. DESIGN: Randomized within-subject design with repeated measures across test conditions. STUDY SAMPLE: Eleven children with mild to moderate hearing loss were evaluated with: (1) Phonak BTE without NLFC, (2) Phonak BTE with NLFC, and (3) Oticon BTE with wideband response extending to 8000 Hz. RESULTS: Use of NLFC provided better detection and recognition of high-frequency stimuli (e.g. /sh/ and /s/). No difference in performance between conditions was observed for speech recognition when measured with the University of Western Ontario (UWO) plurals test and the UWO distinctive features difference test. Finally, there were no differences between conditions on the BKB-SIN test. CONCLUSIONS: Children with mild to moderate hearing loss have good access to high-frequency phonemes presented at fixed levels (e.g. 50 to 60 dBA) with both wideband and NLFC technology. Similarly, sentence recognition in noise was similar with wideband and NLFC. Adaptive test procedures that probe performance at lower input levels showed small but significant improvements in the detection and recognition of the phonemes /s/ and /sh/ with NLFC condition when compared to the NLFC Off and wideband conditions.

Evaluation of wideband frequency responses and nonlinear frequency compression for children with cookie-bite audiometric configurations.

BACKGROUND: Previous research has suggested that use of nonlinear frequency compression (NLFC) can improve audibility for high-frequency sounds and speech recognition of children with moderate to profound high-frequency hearing loss. Furthermore, previous studies have generally found no detriment associated with the use of NLFC. However, there have been no published studies examining the effect of NLFC on the performance of children with cookie-bite audiometric configurations. For this configuration of hearing loss, frequency-lowering processing will likely move high-frequency sounds to a lower frequency range at which a greater degree of hearing loss exists. PURPOSE: The purpose of this study was to evaluate and compare the effects of wideband amplification and NLFC on high-frequency audibility and speech recognition of children with cookie-bite audiometric configurations. RESEARCH DESIGN: This study consisted of a within-participant design with repeated measures across test conditions. STUDY SAMPLE: Seven children, ages 6-13 yr, with cookie-bite audiometric configurations and normal hearing or mild hearing loss at 6000 and 8000 Hz, were recruited. INTERVENTION: Participants were fitted with Phonak Nios S H2O III behind-the-ear hearing aids and Oticon Safari 300 behind-the-ear hearing aids. DATA COLLECTION: The participants were evaluated after three 4-to 6-wk intervals: (1) Phonak Nios S H2O III without NLFC, (2) Phonak Nios S H2O III with NLFC, and (3) Oticon Safari 300 with wideband frequency response extending to 8000 Hz. The order in which each technology was used was counterbalanced across participants. High-frequency audibility was evaluated by assessing aided thresholds (dB SPL) for warble tones and the high-frequency phonemes /sh/ and /s/. Speech recognition in quiet was measured with the University of Western Ontario (UWO) Plurals Test, the UWO Distinctive Features Difference (DFD) Test, and the Phoneme Perception Test vowel-consonant-vowel nonsense syllable test. Sentence recognition in noise was evaluated with the Bamford-Kowal-Bench Speech-In-Noise (BKB-SIN) Test. ANALYSIS: Repeated-measures analyses of variance were used to analyze the data collected in this study. The results across the three different conditions were compared. RESULTS: No difference in performance across conditions was observed for detection of high-frequency warble tones and the speech sounds /sh/ and /s/. No significant difference was seen across conditions for speech recognition in quiet when measured with the UWO Plurals Test, the UWO-DFD Test, and the Phoneme Perception Test vowel-consonant-vowel nonsense syllable test. Finally, there were also no differences across conditions on the BKB-SIN Test. CONCLUSIONS: These results suggest that NLFC does not degrade or improve audibility for and recognition of high-frequency speech sounds as well as sentence recognition in noise when compared with wideband amplification for children with cookie-bite audiometric configurations.