Transcriptional programming of dendritic cells for enhanced MHC class II antigen presentation.

CD11b(+) dendritic cells (DCs) seem to be specialized for presenting antigens via major histocompatibility (MHC) class II complexes to stimulate helper T cells, but the genetic and regulatory basis for this is not established. Conditional deletion of Irf4 resulted in loss of CD11b(+) DCs, impaired formation of peptide-MHC class II complexes and defective priming of helper T cells but not of cytotoxic T lymphocyte (CTL) responses. Gene expression and chromatin immunoprecipitation followed by deep sequencing (ChIP-Seq) analyses delineated an IRF4-dependent regulatory module that programs enhanced MHC class II antigen presentation. Expression of the transcription factor IRF4 but not of IRF8 restored the ability of IRF4-deficient DCs to efficiently process and present antigen to MHC class II-restricted T cells and promote helper T cell responses. We propose that the evolutionary divergence of IRF4 and IRF8 facilitated the specialization of DC subsets for distinct modes of antigen presentation and priming of helper T cell versus CTL responses.

One-pot synthesis of g-C3N4/N-doped CeO2 nanocomposites and their potential visible light-driven photocatalytic degradation of methylene blue dye.

In the pursuit of efficient photocatalytic materials for environmental applications, a new series of g-C3N4/N-doped CeO2 nanocomposites (g-C3N4/N-CeO2 NCs) was synthesized using a straightforward dispersion method. These nanocomposites were systematically characterized to understand their structural, optical, and chemical properties. The photocatalytic performance of g-C3N4/N-CeO2 NCs was evaluated by investigating their ability to degrade methylene blue (MB) dye, a model organic pollutant. The results demonstrate that the integration of g-C3N4 with N-doped CeO2 NCs reduces the optical energy gap compared to pristine N-doped CeO2, leading to enhanced photocatalytic efficiency. It is benefited from the existence of g-C3N4/N-CeO2 NCs not only in promoting the charge separation and inhibits the fast charge recombination but also in improving photocatalytic oxidation performance. Hence, this study highlights the potential of g-C3N4/N-CeO2 NCs as promising candidates for various photocatalytic applications, contributing to the advancement of sustainable environmental remediation technologies.

Acoustic component programming in children with cochlear implants using electrocochleography.

OBJECTIVE: Objective measurements improve reliability and effectiveness of hearing assessment and cochlear implant (CI) programming in young children. In CI recipients with acoustic hearing in the implanted ear, electrocochleography (ECochG) can be conducted using intracochlear electrodes. The cochlear microphonic (CM) portion of ECochG has been shown to correlate with pure-tone audiometric thresholds in adult and paediatric CI recipients. Our goal was to determine if ECochG thresholds can be used to appropriately fit the acoustic component to the implanted ear in children. DESIGN: Prospective. STUDY SAMPLE: Eight children (aged 3.5-15.5 years, 10 ears) implanted with Advanced Bionics HiFocus Mid-Scala electrode array were recruited. CI ear acoustic thresholds were measured behaviourally and via ECochG. Two acoustic component enabled CI programs were created using the two sets of thresholds. Age and language appropriate speech outcomes and subjective feedback were obtained. RESULTS: Speech scores were equivalent with the behavioural and ECochG thresholds programs. Subjectively, the ECochG thresholds program was preferred by 7/8 subjects. One subject preferred to use an electric only program. CONCLUSION: Our data suggest that ECochG thresholds can be used to supplement the behavioural clinical methods and aid the reliable fitting of the acoustic component in paediatric CI recipients.

The Value of Unilateral CIs, CI-CROS and Bilateral CIs, with and without Beamformer Microphones, for Speech Understanding in a Simulation of a Restaurant Environment.

OBJECTIVE: Our primary aim was to determine, in a simulation of a crowded restaurant, the value to speech understanding of (i) a unilateral cochlear implant (CI), (ii) a CI plus CROS (contralateral routing of signals) aid system and (iii) bilateral CIs when tested with and without beamforming microphones. DESIGN: The listeners were 7 CI listeners who had used bilateral CIs for an average of 9 years. The listeners were tested with three device configurations (bilateral CI, unilateral CI + CROS, and unilateral CI), two signal processing conditions (without and with beamformers) and with speech either from +90°, -90°, or from the front. Speech understanding scores for the TIMIT sentences were obtained in the 8-loudspeaker R-SPACETM test environment - an environment which simulates listening in a crowded restaurant. RESULTS: In the unilateral condition, speech understanding, relative to speech directed to the CI ear, fell by 17% when speech was from the front and fell 28% when speech was to the side opposite the CI. These deficits were overcome with both CI-CROS and bilateral CIs, and scores for the two devices did not differ significantly for any location of speech input. Beamformer microphones improved speech understanding for speech from the front and depressed speech understanding for speech from the sides for all device configurations. Patients with bilateral CIs and beamformers achieved slightly, but significantly, higher scores for speech from the front than patients with CI-CROS and beamformers. CONCLUSIONS: CI-CROS is a valuable addition to the hardware options available to patients fit with a single CI. For patients fit with bilateral CIs, bilateral beamformers are a valuable addition in the condition of speech coming from in front of the listener. The small differences in performance in the CI-CROS and bilateral CI conditions suggest that patient preference for bilateral CIs is based largely on factors other than speech understanding in noise.

CROS or hearing aid? Selecting the ideal solution for unilateral CI patients with limited aidable hearing in the contralateral ear.

A hearing aid or a contralateral routing of signal device are options for unilateral cochlear implant listeners with limited hearing in the unimplanted ear; however, it is uncertain which device provides greater benefit beyond unilateral listening alone. Eighteen unilateral cochlear implant listeners participated in this prospective, within-participants, repeated measures study. Participants were tested with the cochlear implant alone, cochlear implant + hearing aid, and cochlear implant + contralateral routing of signal device configurations with a one-month take-home period between each in-person visit. Audiograms, speech perception in noise, and lateralization were evaluated. Subjective feedback was obtained via questionnaires. Marked improvement in speech in noise and non-implanted ear lateralization accuracy were observed with the addition of a contralateral hearing aid. There were no significant differences in speech recognition between listening configurations. However, the chronic device use questionnaires and the final device selection showed a clear preference for the hearing aid in spatial awareness and communication domains. Individuals with limited hearing in their unimplanted ears demonstrate significant improvement with the addition of a contralateral device. Subjective questionnaires somewhat contrast with clinic-based outcome measures, highlighting the delicate decision-making process involved in clinically advising one device or another to maximize communication benefits.

Studies on bilateral cochlear implants at the University of Wisconsin's Binaural Hearing and Speech Laboratory.

This report highlights research projects relevant to binaural and spatial hearing in adults and children. In the past decade we have made progress in understanding the impact of bilateral cochlear implants (BiCIs) on performance in adults and children. However, BiCI users typically do not perform as well as normal hearing (NH) listeners. In this article we describe the benefits from BiCIs compared with a single cochlear implant (CI), focusing on measures of spatial hearing and speech understanding in noise. We highlight the fact that in BiCI listening the devices in the two ears are not coordinated; thus binaural spatial cues that are available to NH listeners are not available to BiCI users. Through the use of research processors that carefully control the stimulus delivered to each electrode in each ear, we are able to preserve binaural cues and deliver them with fidelity to BiCI users. Results from those studies are discussed as well, with a focus on the effect of age at onset of deafness and plasticity of binaural sensitivity. Our work with children has expanded both in number of subjects tested and age range included. We have now tested dozens of children ranging in age from 2 to 14 yr. Our findings suggest that spatial hearing abilities emerge with bilateral experience. While we originally focused on studying performance in free field, where real world listening experiments are conducted, more recently we have begun to conduct studies under carefully controlled binaural stimulation conditions with children as well. We have also studied language acquisition and speech perception and production in young CI users. Finally, a running theme of this research program is the systematic investigation of the numerous factors that contribute to spatial and binaural hearing in BiCI users. By using CI simulations (with vocoders) and studying NH listeners under degraded listening conditions, we are able to tease apart limitations due to the hardware/software of the CI systems from limitations due to neural pathology.

Clinical Practice Patterns of Fitting Advanced Device Features in Children With Cochlear Implants.

PURPOSE: The purpose of this study was to identify common clinical practice patterns for providing advanced noise management features in children with cochlear implants (CIs) and evaluate trends in consideration of clinician experience and comfort with CI manufacturer-specific technology. METHOD: A mixed-model survey including quantitative and qualitative questions regarding providing advanced noise management features in the pediatric CI population was collected electronically via research electronic data capture. Survey questions spanned approach/philosophy toward provision of features, age of provision, and demographics of respondents. Descriptive statistics were completed to define common clinical practice patterns and demographic information. RESULTS: A total of 160 pediatric audiologists from 35 U.S. States and five Canadian provinces completed the survey. Most audiologists (73.8%) reported enabling automatic directional microphones, and a vast majority (91%) reported enabling advanced noise processing features such as automatic noise cancellers, wind noise cancellers, and impulse noise cancellers in recipients' main programs. Audiologists ranked features in terms of importance for a school-age child with the top three ranked as automatic noise reduction, automatic directional microphones, and concha-level microphones. Importance of child-specific factors varied depending upon the specific feature of interest. CONCLUSIONS: Variability exists among providers in enabling advanced noise management features for pediatric CI recipients. Multiple factors, including patient characteristics, provider characteristics, and limited evidence-based guidance, could account for much of the variation. Overall, there is a trend toward automaticity for noise management. Additional studies are warranted to provide the evidence base for confidently programming advanced features for children using CIs.

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.

Can the use of the CROS system provide head shadow effect contribution to unilateral Cochlear Implant Users?

PURPOSE: The aim of this study was to evaluate the contribution of the CROS system on the head shadow effect in unilateral implant users. METHODS: Prospective cross-sectional study, approved by the ethics committee under protocol 2.128.869. Eleven adults with post-lingual deafness users of unilateral Advanced Bionics CI were selected. Speech recognition was evaluated with recorded words presented at 65dBA at 0o azimuth and at 90o on the side contralateral to the CI, with noise at 55dBA, using CI alone and CI + CROS system. The results were analyzed using paired t-test with a 0.05 alpha. RESULTS: The mean speech recognition scores were significantly better with CI + CROS in relation to the condition of CI alone (p <0.05, p <0.005 and p <0.005 respectively). In the presentation at 0o azimuth, no significant differences were found. CONCLUSION: Users of unilateral CI without useful residual hearing for the use of hearing aids or unable to undergo bilateral surgery can benefit from the CROS device for speech recognition, especially when the speech is presented on the side contralateral to the CI.

Transforming growth factor-beta and notch signaling mediate stem cell differentiation into smooth muscle cells.

The differentiation of stem cells into smooth muscle cells (SMCs) plays an important role in vascular development and remodeling. In addition, stem cells represent a potential source of SMCs for regenerative medicine applications such as constructing vascular grafts. Previous studies have suggested that various biochemical factors, including transforming growth factor-beta (TGF-beta) and the Notch pathway, may play important roles in vascular differentiation. However, the interactions of these two signaling pathways in the differentiation of bone marrow mesenchymal stem cells (MSCs) have not been clearly defined. In this study, we profiled the gene expression in MSCs in response to TGF-beta, and showed that TGF-beta induced Notch ligand Jagged 1 (JAG1) and SMC markers, including smooth muscle alpha-actin (ACTA2), calponin 1 (CNN1), and myocardin (MYOCD), which were dependent on the activation of SMAD3 and Rho kinase. In addition, knocking down JAG1 expression partially blocked ACTA2 and CNN1 expression and completely blocked MYOCD expression, suggesting that JAG1 plays an important role in TGF-beta-induced expression of SMC markers. On the other hand, the activation of Notch signaling induced the expression of SMC markers in MSCs and human embryonic stem cells (hESCs). Notch activation in hESCs also resulted in an increase of neural markers and a decrease of endothelial markers. These results suggest that Notch signaling mediates TGF-beta regulation of MSC differentiation and that Notch signaling induces the differentiation of MSCs and hESCs into SMCs, which represents a novel mechanism involved in stem cell differentiation.

The Benefit of Remote and On-Ear Directional Microphone Technology Persists in the Presence of Visual Information.

BACKGROUND: Both the Roger remote microphone and on-ear, adaptive beamforming technologies (e.g., Phonak UltraZoom) have been shown to improve speech understanding in noise for cochlear implant (CI) listeners when tested in audio-only (A-only) test environments. PURPOSE: Our aim was to determine if adult and pediatric CI recipients benefited from these technologies in a more common environment-one in which both audio and visual cues were available and when overall performance was high. STUDY SAMPLE: Ten adult CI listeners (Experiment 1) and seven pediatric CI listeners (Experiment 2) were tested. DESIGN: Adults were tested in quiet and in two levels of noise (level 1 and level 2) in A-only and audio-visual (AV) environments. There were four device conditions: (1) an ear canal-level, omnidirectional microphone (T-mic) in quiet, (2) the T-mic in noise, (3) an adaptive directional mic (UltraZoom) in noise, and (4) a wireless, remote mic (Roger Pen) in noise. Pediatric listeners were tested in quiet and in level 1 noise in A-only and AV environments. The test conditions were: (1) a behind-the-ear level omnidirectional mic (processor mic) in quiet, (2) the processor mic in noise, (3) the T-mic in noise, and (4) the Roger Pen in noise. DATA COLLECTION AND ANALYSES: In each test condition, sentence understanding was assessed (percent correct) and ease of listening ratings were obtained. The sentence understanding data were entered into repeated-measures analyses of variance. RESULTS: For both adult and pediatric listeners in the AV test conditions in level 1 noise, performance with the Roger Pen was significantly higher than with the T-mic. For both populations, performance in level 1 noise with the Roger Pen approached the level of baseline performance in quiet. Ease of listening in noise was rated higher in the Roger Pen conditions than in the T-mic or processor mic conditions in both A-only and AV test conditions. CONCLUSION: The Roger remote mic and on-ear directional mic technologies benefit both speech understanding and ease of listening in a realistic laboratory test environment and are likely do the same in real-world listening environments.

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.

Computational models of the Notch network elucidate mechanisms of context-dependent signaling.

The Notch signaling pathway controls numerous cell fate decisions during development and adulthood through diverse mechanisms. Thus, whereas it functions as an oscillator during somitogenesis, it can mediate an all-or-none cell fate switch to influence pattern formation in various tissues during development. Furthermore, while in some contexts continuous Notch signaling is required, in others a transient Notch signal is sufficient to influence cell fate decisions. However, the signaling mechanisms that underlie these diverse behaviors in different cellular contexts have not been understood. Notch1 along with two downstream transcription factors hes1 and RBP-Jk forms an intricate network of positive and negative feedback loops, and we have implemented a systems biology approach to computationally study this gene regulation network. Our results indicate that the system exhibits bistability and is capable of switching states at a critical level of Notch signaling initiated by its ligand Delta in a particular range of parameter values. In this mode, transient activation of Delta is also capable of inducing prolonged high expression of Hes1, mimicking the "ON" state depending on the intensity and duration of the signal. Furthermore, this system is highly sensitive to certain model parameters and can transition from functioning as a bistable switch to an oscillator by tuning a single parameter value. This parameter, the transcriptional repression constant of hes1, can thus qualitatively govern the behavior of the signaling network. In addition, we find that the system is able to dampen and reduce the effects of biological noise that arise from stochastic effects in gene expression for systems that respond quickly to Notch signaling.This work thus helps our understanding of an important cell fate control system and begins to elucidate how this context dependent signaling system can be modulated in different cellular settings to exhibit entirely different behaviors.

Human frequency-following response to speech-like sounds: correlates of off-frequency masking.

Off-frequency masking of the second formant by energy at the first formant has been shown to influence both identification and discrimination of the second formant in normal-hearing and hearing-impaired listeners. While both excitatory spread and two-tone suppression have been implicated in this simultaneous masking, their relative contribution has been shown to depend on both the level of the masker and the frequency separation between the probe and the masker. Off-frequency masking effects were evaluated in 10 normal-hearing human adults using the frequency-following response (FFR) to two two-tone approximations of vowel stimuli (/a/ and /u/). In the first experiment, the masking effect of F(1) on F(2) was evaluated by attenuating the level of F(1) relative to a fixed F(2) level. In the second experiment, the masking effect was evaluated by increasing the frequency separation between F(1) and F(2) using F(2) frequency as the variable. Results revealed that both attenuation of the F(1) level, and increasing the frequency separation between F(1) and F(2) increased the magnitude of the FFR component at F(2). These results are consistent with a release from off-frequency masking. Given that the results presented here are for high signal and masker levels and for relatively smaller frequency separation between the masker and the probe, it is possible that both suppression and excitatory spread contributed to the masking effects observed in our data.

Effect of age at onset of deafness on binaural sensitivity in electric hearing in humans.

Sensitivity to binaural cues was studied in 11 bilateral cochlear implant users, all of whom received both of their cochlear implants as adults, but who varied in the age at onset of deafness, from pre-lingual to childhood-onset to adult-onset. Sensitivity to interaural timing difference (ITD) and interaural level difference (ILD) cues was measured at basal, middle, and apical pitch-matched places of stimulation along the cochlear arrays, using a stimulation rate of 100 Hz. Results show that there is a trend for people whose onset of deafness occurred during adult life or late childhood to retain at least some sensitivity to ITDs, whereas people with onset of deafness earlier in life were insensitive to ITDs. In contrast, ILD cue sensitivity was present in all subjects. There were no effects of place of stimulation on binaural sensitivity, suggesting that there is no indication of a dependence of ITD sensitivity on apical vs basal electrode location.

Evaluation of a novel bimodal fitting formula in Advanced Bionics cochlear implant recipients.

Purpose: The study's objectives were to (1) evaluate benefit from a novel bimodal fitting formula (Adaptive Phonak Digital Bimodal Fitting Formula [APDB]), and (2) compare outcomes with APDB and a traditional fitting formula (NAL-NL2). Methods: This prospective study evaluated outcomes in ten adults with unilateral Advanced Bionics (AB) cochlear implants (CI). Participants were tested bimodally with NAL-NL2 and APDB programed on Naída Link UP HAs. Measures of speech perception, sound quality, and preference were obtained with two bimodal configurations (CI + HANAL-NL2 and CI + HAAPDB). Participants used the CI + HAAPDB configuration for an acclimation period, after which measures were repeated. Results: Significant bimodal benefit was measured from both HA fitting formulae for speech perception in noise compared to the CI-only condition. Improved individual outcomes with the APDB were observed, but group differences were not statistically significant. Participants reported subjective benefit from APDB on blind comparisons of preference and sound quality. Conclusions: Significant benefit was found with both bimodal conditions compared to the CI-only condition; however, bimodal speech perception results were not significantly different. Users reported benefit from the APDB formula over NAL-NL2 formula. Due to individual improved speech perception and overall subjective preference for APDB, clinicians should consider APDB with AB CI recipients.

Using Microphone Technology to Improve Speech Perception in Noise in Children with Cochlear Implants.

BACKGROUND: Cochlear implant (CI) users are affected more than their normal hearing (NH) peers by the negative consequences of background noise on speech understanding. Research has shown that adult CI users can improve their speech recognition in challenging listening environments by using dual-microphone beamformers, such as adaptive directional microphones (ADMs) and wireless remote microphones (RMs). The suitability of these microphone technologies for use in children with CIs is not well-understood nor widely accepted. PURPOSE: To assess the benefit of ADM or RM technology on speech perception in background noise in children and adolescents with cochlear implants (CIs) with no previous or current use of ADM or RM. RESEARCH DESIGN: Mixed, repeated measures design. STUDY SAMPLE: Twenty (20) children, ten (10) CI users (mean age 14.3 yrs) who used Advanced Bionics HiRes90K implants with research Naida processors, and ten (10) NH age-matched controls participated in this prospective study. INTERVENTION: CI users listened with an ear-canal level microphone, T-Mic (TM), an ADM, and a wireless RM at different audio-mixing ratios. Speech understanding with five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%) was evaluated in quiet and in noise. DATA COLLECTION AND ANALYSIS: Speech perception ability was measured using children's spondee words to obtain a speech recognition threshold for 80% accuracy (SRT80%) in 20-talker babble where the listener sat in a sound booth 1 m (3.28') from the target speech (front) and noise (behind) to test five microphone settings (TM 100%, ADM, RM + TM 50/50, RM + TM 75/25, RM 100%). Group performance-intensity functions were computed for each listening condition to show the effects of microphone configuration with respect to signal-to-noise ratio (SNR). A difference score (CI Group minus NH Group) was computed to show the effect of microphone technology at different SNRs relative to NH. Statistical analysis using a repeated-measures analysis of variance evaluated the effects of the microphone configurations on SRT80% and performance at SNRs. Between-groups analysis of variance was used to compare the CI group with the NH group. RESULTS: The speech recognition was significantly poorer for children with CI than children with NH in quiet and in noise when using the TM alone. Adding the ADM or RM provided a significant improvement in speech recognition for the CI group over use of the TM alone in noise (mean dB advantage ranged from 5.8 for ADM to 16 for RM100). When children with CI used the RM75 or RM100 in background babble, speech recognition was not statistically different from the group with NH. CONCLUSION: Speech recognition in noise performance improved with the use of ADM and RM100 or RM75 over TM-only for children with CIs. Alhough children with CI remain at a disadvantage as compared with NH children in quiet and more favorable SNRs, microphone technology can enhance performance for some children with CI to match that of NH peers in contexts with negative SNRs.

Can the use of the CROS system provide head shadow effect contribution to unilateral Cochlear Implant Users? / O Sistema CROS pode oferecer contribuição do efeito sombra da cabeça a usuários de implante coclear unilateral?

ABSTRACT Purpose The aim of this study was to evaluate the contribution of the CROS system on the head shadow effect in unilateral implant users. Methods Prospective cross-sectional study, approved by the ethics committee under protocol 2.128.869. Eleven adults with post-lingual deafness users of unilateral Advanced Bionics CI were selected. Speech recognition was evaluated with recorded words presented at 65dBA at 0o azimuth and at 90o on the side contralateral to the CI, with noise at 55dBA, using CI alone and CI + CROS system. The results were analyzed using paired t-test with a 0.05 alpha. Results The mean speech recognition scores were significantly better with CI + CROS in relation to the condition of CI alone (p <0.05, p <0.005 and p <0.005 respectively). In the presentation at 0o azimuth, no significant differences were found. Conclusion Users of unilateral CI without useful residual hearing for the use of hearing aids or unable to undergo bilateral surgery can benefit from the CROS device for speech recognition, especially when the speech is presented on the side contralateral to the CI.

RESUMO Objetivo O objetivo deste estudo foi avaliar o efeito do sistema CROS em fenômenos como efeito sombra da cabeça em usuários de implante coclear unilateral. Método Estudo transversal prospectivo, aprovado pelo conselho de ética sob protocolo 2.128.869. Onze adultos com surdez de instalação pós-lingual usuários de IC Advanced Bionics unilateral foram selecionados. O reconhecimento de fala foi avaliado com palavras gravadas apresentadas a 65dBA a 0o azimute e a (90o no lado contralateral ao IC), com ruído a 55dBA, usando somente o IC e IC+sistema CROS. Os resultados foram analisados usando teste t pareado com alfa de 0,05. Resultados Os escores médios de reconhecimento de fala foram significativamente melhores com IC + CROS em relação à condição apenas IC (p <0,05, p <0,005 e p <0,005 respectivamente). Na apresentação à frente não foram encontradas diferenças significantes. Conclusão Os usuários de IC unilateral sem resíduo útil para uso de prótese auditiva ou impossibilitados de submeter-se à cirurgia bilateral podem se beneficiar do dispositivo CROS para o reconhecimento de fala, sobretudo quando a fala for apresentada ao lado contralateral ao IC.

Participant-generated Cochlear Implant Programs: Speech Recognition, Sound Quality, and Satisfaction.

OBJECTIVE: To determine whether patient-derived programming of one's cochlear implant (CI) stimulation levels may affect performance outcomes. BACKGROUND: Increases in patient population, device complexity, outcome expectations, and clinician responsibility have demonstrated the necessity for improved clinical efficiency. METHODS: Eighteen postlingually deafened adult CI recipients (mean = 53 years; range, 24-83 years) participated in a repeated-measures, within-participant study designed to compare their baseline listening program to an experimental program they created. RESULTS: No significant group differences in aided sound-field thresholds, monosyllabic word recognition, speech understanding in quiet, speech understanding in noise, nor spectral modulation detection (SMD) were observed (p > 0.05). Four ears (17%) improved with the experimental program for speech presented at 45 dB SPL and two ears (9%) performed worse. Six ears (27.3%) improved significantly with the self-fit program at +10 dB signal-to-noise ratio (SNR) and four ears (26.6%) improved in speech understanding at +5 dB SNR. No individual scored significantly worse when speech was presented in quiet at 60 dB SPL or in any of the noise conditions tested. All but one participant opted to keep at least one of the self-fitting programs at the completion of this study. Participants viewed the process of creating their program more favorably (t = 2.11, p = 0.012) and thought creating the program was easier than the traditional fitting methodology (t = 2.12, p = 0.003). Average time to create the self-fit program was 10 minutes, 10 seconds (mean = 9:22; range, 4:46-24:40). CONCLUSIONS: Allowing experienced adult CI recipients to set their own stimulation levels without clinical guidance is not detrimental to success.

In situ stem cell therapy: novel targets, familiar challenges.

Tissue engineering approaches for expanding, differentiating and engrafting embryonic or adult stem cells have significant potential for tissue repair but harnessing endogenous stem cell populations offers numerous advantages over these approaches. There has been rapid basic biological progress in the identification of stem cell niches throughout the body and the molecular factors that regulate their function. These niches represent novel therapeutic targets and efforts to use them involve the familiar challenges of delivering molecular medicines in vivo. Here we review recent progress in the use of genes, proteins and small molecules for in situ stem cell control and manipulation, with a focus on using stem cells of the central nervous system for neuroregeneration.