Auditory Dysfunction Among Individuals With Neurofibromatosis Type 1.

Importance: Neurofibromatosis type 1 (NF1) affects hearing through disruption of central auditory processing. The mechanisms, functional severity, and management implications are unclear. Objective: To investigate auditory neural dysfunction and its perceptual consequences in individuals with NF1. Design, Setting, and Participants: This case-control study included children and adults with NF1 and control participants matched on age, sex, and hearing level. Patients were recruited through specialist neurofibromatosis and neurogenetic outpatient clinics between April and September 2019. An evaluation of auditory neural activity, monaural/binaural processing, and functional hearing was conducted. Diffusion-weighted magnetic resonance imaging (MRI) data were collected from a subset of participants (10 children with NF1 and 10 matched control participants) and evaluated using a fixel-based analysis of apparent fiber density. Main Outcomes and Measures: Type and severity of auditory dysfunction evaluated via laboratory testing and questionnaire data. Results: A total of 44 participants (18 [41%] female individuals) with NF1 with a mean (SD) age of 16.9 (10.7) years and 44 control participants (18 [41%] female individuals) with a mean (SD) age of 17.2 (10.2) years were included in the study. Overall, 11 participants (25%) with NF1 presented with evidence of auditory neural dysfunction, including absent, delayed, or low amplitude electrophysiological responses from the auditory nerve and/or brainstem, compared with 1 participant (2%) in the control group (odds ratio [OR], 13.03; 95% CI, 1.59-106.95). Furthermore, 14 participants (32%) with NF1 showed clinically abnormal speech perception in background noise compared with 1 participant (2%) in the control group (OR, 20.07; 95% CI, 2.50-160.89). Analysis of diffusion-weighted MRI data of participants with NF1 showed significantly lower apparent fiber density within the ascending auditory brainstem pathways. The regions identified corresponded to the neural dysfunction measured using electrophysiological assessment. Conclusions and Relevance: The findings of this case-control study could represent new neurobiological and clinical features of NF1. Auditory dysfunction severe enough to impede developmental progress in children and restrict communication in older participants is a common neurobiological feature of the disorder.

Longitudinal auditory pathophysiology following mild blast-induced trauma.

Blast-induced hearing difficulties affect thousands of veterans and civilians. The long-term impact of even a mild blast exposure on the central auditory system is hypothesized to contribute to lasting behavioral complaints associated with mild blast traumatic brain injury (bTBI). Although recovery from mild blast has been studied separately over brief or long time windows, few, if any, studies have investigated recovery longitudinally over short-term and longer-term (months) time windows. Specifically, many peripheral measures of auditory function either recover or exhibit subclinical deficits, masking deficits in processing complex, real-world stimuli that may recover differently. Thus, examining the acute time course and pattern of neurophysiological impairment using appropriate stimuli is critical to better understanding and intervening in bTBI-induced auditory system impairments. Here, we compared auditory brainstem response, middle-latency auditory-evoked potentials, and envelope following responses. Stimuli were clicks, tone pips, amplitude-modulated tones in quiet and in noise, and speech-like stimuli (iterated rippled noise pitch contours) in adult male rats subjected to mild blast and sham exposure over the course of 2 mo. We found that blast animals demonstrated drastic threshold increases and auditory transmission deficits immediately after blast exposure, followed by substantial recovery during the window of 7-14 days postblast, although with some deficits remaining even after 2 mo. Challenging conditions and speech-like stimuli can better elucidate mild bTBI-induced auditory deficit during this period. Our results suggest multiphasic recovery and therefore potentially different time windows for treatment, and deficits can be best observed using a small battery of sound stimuli.NEW & NOTEWORTHY Few studies on blast-induced hearing deficits go beyond simple sounds and sparsely track postexposure. Therefore, the recovery arc for potential therapies and real-world listening is poorly understood. Evidence suggested multiple recovery phases over 2 mo postexposure. Hearing thresholds largely recovered within 14 days and partially explained recovery. However, midlatency responses, responses to amplitude modulation in noise, and speech-like pitch sweeps exhibited extended changes, implying persistent central auditory deficits and the importance of subclinical threshold shifts.

Altered mapping of sound frequency to cochlear place in ears with endolymphatic hydrops provide insight into the pitch anomaly of diplacusis.

A fundamental property of mammalian hearing is the conversion of sound pressure into a frequency-specific place of maximum vibration along the cochlear length, thereby creating a tonotopic map. The tonotopic map makes possible systematic frequency tuning across auditory-nerve fibers, which enables the brain to use pitch to separate sounds from different environmental sources and process the speech and music that connects us to people and the world. Sometimes a tone has a different pitch in the left and right ears, a perceptual anomaly known as diplacusis. Diplacusis has been attributed to a change in the cochlear frequency-place map, but the hypothesized abnormal cochlear map has never been demonstrated. Here we assess cochlear frequency-place maps in guinea-pig ears with experimentally-induced endolymphatic hydrops, a hallmark of Ménière's disease. Our findings are consistent with the hypothesis that diplacusis is due to an altered cochlear map. Map changes can lead to altered pitch, but the size of the pitch change is also affected by neural synchrony. Our data show that the cochlear frequency-place map is not fixed but can be altered by endolymphatic hydrops. Map changes should be considered in assessing hearing pathologies and treatments.

Endoscopic Ossiculoplasty for the Management of Isolated Congenital Ossicular Chain Malformation: Surgical Results in 16 Ears.

OBJECTIVE: The aim of this study is to describe the clinical characteristics and intraoperative findings and further evaluate the efficacy of endoscopic ossiculoplasty for the management of isolated congenital ossicular chain malformation. METHODS: A retrospective study was performed on 16 ears (15 patients) with the isolated congenital ossicular chain malformation who underwent endoscopic ossiculoplasty in our department from May 2017 to January 2019. Endoscopic exploratory tympanotomy was conducted to check the ossicular chain; at the same time, endoscopic ossiculoplasty was performed depending on intraoperative findings. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps (ABGs) were measured before and after surgery, and the hearing outcome was assessed at 6 months postoperatively. RESULTS: The most common malformations of ossicular chain were the missing of the incus long process and stapes suprastructure. A serial assessment of the hearing status was conducted before and 6 months after surgery. It showed the mean postoperative pure-tone average (PTA) was significantly reduced, and the mean postoperative ABG was obviously closed, respectively (P < .001). The mean PTA gain was 36.3 ± 8.6 dB, and the ABG closure was 35.1 ± 8.3 dB; ABG closure to 20 dB or less and ABG closure to 10 dB or less were achieved in 14 cases (87.5%) and 5 cases (31.3%), respectively. No differences were observed in postoperative hearing outcome between type Ⅲ cases and type Ⅳ cases; however, cases with partial ossicular replacement prosthesis implantation showed a larger hearing gain (P = .049) and a higher proportion of postoperative ABG less than 10 dB (P = .021). No facial palsy and significant sensorineural hearing loss occurred; all patients completed the surgery without the need of canalplasty, and the chorda tympani nerve was preserved in all patients. CONCLUSIONS: This research showed endoscopic surgery was effective in the diagnosis and management of isolated congenital ossicular chain malformation; the endoscopic ossiculoplasty provides an alternative method to manage congenital ossicular chain malformation, with comfortable hearing outcome and the advantage of excellent vision and less invasion.

The Prevalence and Severity of Misophonia in a UK Undergraduate Medical Student Population and Validation of the Amsterdam Misophonia Scale.

Misophonia is a condition of abnormal emotional responses to specific auditory stimuli. There is limited information available on the prevalence of this condition. This study aimed to estimate the prevalence of misophonia in an undergraduate medical student population at the University of Nottingham. A secondary aim of this study was to assess the psychometric validity of the Amsterdam Misophonia Scale (A-Miso-S) questionnaire tool in this population. The A-Miso-S was administered online to medical students at the University of Nottingham. To assess the validity of the A-Miso-S, a factor analysis was conducted. To determine prevalence and severity the results of the questionnaire were quantitatively analysed using SPSS. Actor analysis was conducted. Free text responses to one questionnaire item were analysed using a thematic approach. Responses were obtained from 336 individuals. Clinically significant misophonic symptoms appear to be common, effecting 49.1% of the sample population. This is statistically significantly higher prevalence than previous studies have found (p < 0.00001). Using the classification of the A-Miso-S, mild symptoms were seen in 37%, moderate in 12%, severe in 0.3% of participants. No extreme cases were seen. The A-Miso-S was found to be a uni-factorial tool, with good internal consistency. This study has provided new information on misophonia and validity of the A-Miso-S questionnaire in a sample population of UK undergraduate medical students. The results indicate that misophonia is a phenomenon that a significant proportion of medical students experience though only a small subset experience it severely.

Impacts of face coverings on communication: an indirect impact of COVID-19.

OBJECTIVE: To understand the impact of face coverings on hearing and communication. DESIGN: An online survey consisting of closed-set and open-ended questions distributed within the UK to gain insights into experiences of interactions involving face coverings, and of the impact of face coverings on communication. SAMPLE: Four hundred and sixty members of the general public were recruited via snowball sampling. People with hearing loss were intentionally oversampled to more thoroughly assess the effect of face coverings in this group. RESULTS: With few exceptions, participants reported that face coverings negatively impacted hearing, understanding, engagement, and feelings of connection with the speaker. Impacts were greatest when communicating in medical situations. People with hearing loss were significantly more impacted than those without hearing loss. Face coverings impacted communication content, interpersonal connectedness, and willingness to engage in conversation; they increased anxiety and stress, and made communication fatiguing, frustrating and embarrassing - both as a speaker wearing a face covering, and when listening to someone else who is wearing one. CONCLUSIONS: Face coverings have far-reaching impacts on communication for everyone, but especially for people with hearing loss. These findings illustrate the need for communication-friendly face-coverings, and emphasise the need to be communication-aware when wearing a face covering.

Impairment, disability, and handicap associated with hearing problems and voice disorders among Colombian teachers / Deficiencia, discapacidad y minusvalía asociadas a los problemas de voz y audición en profesores colombianos

Objectives: 1. define the occurrence of work-related hearing problems and voice disorders among teachers that have contacted the Colombian National Board of Disability Assessment (NBDA) for follow-up; 2. identify individual associated factors of hearing problems and voice disorders among teachers; 3. assess the limitations and restrictions due to hearing problems and voice disorders among these participants. Methods: Retrospective study. The National Database of the Colombian NBDA was reviewed. Information on distributions of occupation, individual characteristics, and diagnosis code (ICD-10) was analyzed. Results: Communication disorders among teachers that have contacted the Colom-bian NBDA for follow-up included voice disorders, with a prevalence of 51%, and hearing problems, with a prevalence of 7%. Female teachers who have contacted the Colombian NBDA for follow-up were 4 times more likely to be identified as having voice disorders compared with their male colleagues. Conclusions: While teachers that have contacted the Colombian NBDA for fol-low-up have a high occurrence of voice disorders, hearing problems are more likely to be stated as a debilitating condition. One possible explanation is that teachers who contacted the Colombian NBDA for follow-up continued working even when many voice symptoms were evident, while hearing problems would prevent a teacher from interacting with students, thereby affecting the teaching-learning process soon-er. Nevertheless, with both voice and hearing problems, work performance and social interaction is affected, and, therefore, quality of life is reduced.

Objetivos: 1. definir la ocurrencia de problemas de audición y de voz relacionados con el trabajo de docentes que contactaron la Junta Nacional de Evaluación de la Discapacidad de Colombia (NBDA) para su seguimiento; 2. identificar los factores individuales asociados a los problemas de audición y voz entre los profesores; 3. eva-luar las limitaciones y restricciones debidas a problemas de audición y voz asociados al trabajo entre los participantes.Métodos: estudio retrospectivo. Se revisó la Base de Datos Nacional de la NBDA colombiana. Se analizó información sobre distribuciones de ocupación, característi-cas individuales y código de diagnóstico (CIE-10).Resultados: Los trastornos de comunicación entre los docentes que han contacta-do a la NBDA colombiana para seguimiento incluyeron problemas de la voz, con una prevalencia del 51%, y problemas de audición, con una prevalencia del 7%. Las pro-fesoras que se han puesto en contacto con la NBDA colombiana para el seguimiento tenían 4 veces más probabilidades de ser identificadas con trastornos de la voz en comparación con sus colegas masculinos.Conclusiones: Si bien los maestros que contactaron a la NBDA colombiana para el seguimiento tienen una alta incidencia de trastornos de la voz, es más probable que los problemas de audición se consideren una condición debilitante. Una posible ex-plicación es que los maestros que se comunicaron con la NBDA colombiana para el seguimiento continuaron trabajando incluso cuando muchos síntomas vocales eran evidentes, mientras que los problemas de audición evitarían que un maestro inte-ractuara con los estudiantes, afectando así el proceso de enseñanza-aprendizaje. Sin embargo, tanto con los problemas de voz como de audición, el desempeño laboral y la interacción social se ven afectados y, por lo tanto, la calidad de vida se reduce.

Sensory impairment and all-cause mortality among the elderly adults in China: a population-based cohort study.

With age-related functional deterioration, sensory impairment including vision impairment (VI), hearing impairment (HI), and dual sensory impairment (DSI) usually occurred among the elderly population, causing a decrease in functional capacity and quality of life. The study aimed to explore how sensory impairment is associated with the risk of all-cause mortality among the elderly adults in China. We prospectively investigated the association among 37,076 participants enrolled from 1998 to 2019 in the Chinese Longitudinal Healthy Longevity Survey. We also, as a sensitivity analysis, explored the association among 11,365 newly incident sensory impairment participants. Cox regression model with sensory impairment as a time-varying exposure was performed to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs). Compared with participants without sensory impairment, those with VI (HR=1.20, 95% CI: 1.15-1.24), HI (HR=1.26, 95% CI: 1.21-1.31), and DSI (HR: 1.46, 95% CI=1.41-1.52) had significant higher risk of all-cause mortality after adjusting for potential confounders. These associations were robust among subgroup analyses stratified by sex and entry age, and sensitivity analyses performed among newly incident sensory impairment participants. In conclusion, sensory impairment was associated with higher mortality risk among the elderly adults in China.

Comparison of primary musicality development between children with cochlear implants and children with normal hearing.

Background: It is beneficial for CI patients listen to music. However it is necessary to take steps to improve the musicality of CI patients.Objectives: The aims of the study were to evaluate the primary musicality of children with cochlear implants versus those with normal hearing.Material and methods: Children participating in this study were divided into two groups: the cochlear implant group (CI group) and the normal hearing group (NH group). The 'Musical Ears Evaluation Form for Professionals' was used to evaluate the subjects' primary musicality.Results: The scores for overall and the three subcategories of primary musicality in children with cochlear implants and in those with normal hearing also improved significantly over time (p < .05). The score for overall primary musicality was not significantly different between CI and NH groups in the same hearing age (p > .05). There were significant differences between the two groups in the same chronological age (p < .05).Conclusions and significance: The primary musicality in children with cochlear implants was not significantly different from normal hearing ones at the same hearing age. The primary musicality in children with cochlear implants was significantly lower than that of children with normal hearing at the same chronological age.

Multi-level evidence of an allelic hierarchy of USH2A variants in hearing, auditory processing and speech/language outcomes.

Language development builds upon a complex network of interacting subservient systems. It therefore follows that variations in, and subclinical disruptions of, these systems may have secondary effects on emergent language. In this paper, we consider the relationship between genetic variants, hearing, auditory processing and language development. We employ whole genome sequencing in a discovery family to target association and gene x environment interaction analyses in two large population cohorts; the Avon Longitudinal Study of Parents and Children (ALSPAC) and UK10K. These investigations indicate that USH2A variants are associated with altered low-frequency sound perception which, in turn, increases the risk of developmental language disorder. We further show that Ush2a heterozygote mice have low-level hearing impairments, persistent higher-order acoustic processing deficits and altered vocalizations. These findings provide new insights into the complexity of genetic mechanisms serving language development and disorders and the relationships between developmental auditory and neural systems.

Monitoramento eletrofisiológico do sistema auditivo central em crianças nascidas pequenas para a idade gestacional / Electrophysiological follow-up of the central auditory system in children born small for gestational age

RESUMO Objetivo Monitorar o sistema auditivo central de crianças nascidas pequenas para a idade gestacional, por meio da avaliação eletrofisiológica da audição, para verificar a ocorrência de eventuais disfunções neurais nesse sistema. Métodos Estudo longitudinal, cuja casuística foi composta por 23 crianças distribuídas em quatro grupos: 1) grupo de quatro crianças nascidas pequenas para a idade gestacional e a termo; 2) grupo de sete crianças nascidas pequenas para a idade gestacional e pré-termo; 3) grupo de quatro crianças nascidas com peso adequado para a idade gestacional e a termo; 4) grupo de oito crianças nascidas adequadas para a idade gestacional e pré-termo, cuja idade ao final da pesquisa foi de 3 anos (variação entre 34 e 39 meses). O critério de inclusão foi presença bilateral de emissões otoacústicas transientes. Todas as crianças foram submetidas ao potencial evocado auditivo de tronco encefálico ao nascimento, aos 6 meses e aos 3 anos de idade e à pesquisa do potencial evocado auditivo de longa latência aos 3 anos. Resultados crianças nascidas pequenas para a idade gestacional e a termo tiveram maior ocorrência de alterações, em relação aos demais grupos, com aumento da latência das ondas III e V e interpicos I-III e I-V. Todas apresentaram resultados normais no potencial evocado auditivo de longa latência. Conclusão Crianças nascidas pequenas para a idade gestacional e a termo apresentam disfunções na condução neural no tronco encefálico e devem ser consideradas de risco para alterações do desenvolvimento das habilidades auditivas necessárias para garantir qualidade de processamento da informação acústica.

ABSTRACT Purpose To follow up the central auditory system of children born small for gestational age, through electrophysiological evaluation of hearing, in order to verify the occurrence of possible neural dysfunctions in this system. Methods A longitudinal study was carried out with 23 children divided into four groups: Term-born group, subdivided into small for gestational age (four children) and four children born with appropriate weight for gestational age, whose age at the end of the research was three years old. Preterm group subdivided into small for gestational age (seven children), and appropriate for gestational age (eight children), whose corrected age, at the end of the research was three years old. All children were subjected to assessment of auditory brainstem auditory evoked potentials at birth, at six months and at three years of age, and Long-Latency Auditory Evoked Potential at three years. Results children born at term and small for gestational age had a higher occurrence of hearing alterations in relation to the other groups, with increased latency of waves III and V and interpeaks I-III and I-V. All children presented normal evaluation in the Long-Latency Auditory Evoked Potential. Conclusion Children born term and small for gestational age present dysfunctions in neural conduction in the brainstem and should be considered at risk for alterations in the development of the auditory skills that are necessary to guarantee quality of acoustic information processing.

[Health care of people with visual or hearing disabilities]. / Estado actual de la atención sanitaria de personas con discapacidad auditiva y visual: una revisión breve.

Visual or hearing disabilities account for 20% of people reporting some sort of disability. We performed a literature review about the interaction that people with visual or hearing disabilities have with the health care system. We found that these people report a lower quality of life and have a higher frequency of physical and psychological ailments. They also have difficulties to obtain an adequate health care and report a paucity of trained professionals to take care of them.

Feasibility of early activation after cochlear implantation.

OBJECTIVES: The purpose of the study is to investigate feasibility of early activation after cochlear implantation by evaluating long-term impedance change and speech perception. DESIGN: Case-control study SETTING: Between July 2015 and December 2016, we prospectively enrolled 20 subjects for early activation (within 24 hours after cochlear implantation). On the other hand, from November 2013 to July 2015, 20 age- and sex-matched control subjects from the database of cochlear implantees treated with conventional activation schedule (4 weeks after surgery) were retrospectively enrolled. PARTICIPANT: Forty patients who underwent cochlear implantation surgeries. MAIN OUTCOME MEASURES: The series impedance and speech perception score of both groups were compared. RESULTS: No statistical difference in long-term follow-up between the two groups was found using GEEs and multivariate analysis. In the early activation group, impedance reached a steady level by the 2nd postoperative week, and the hearing perception ability significantly improved by the 4th postoperative week. CONCLUSION: This comparative study illustrated sequential impedance data during early activation (24 hours) and conventional activation (4 weeks) after CI surgery. There were no major complications in either group, and the safety of early activation with respect to impedance changes, postoperative residual hearing preservation and speech perception scores were non-inferior to that of the conventional group. Therefore, in this study, we established the feasibility of early activation 24 hours after cochlear implantation.

Effects of type 1 diabetes mellitus on efferent auditory system in children and adolescents.

AIM: To investigate whether type 1 diabetes mellitus (T1DM) could affect the efferent auditory system by analyzing the relationship between the activation of the medial olivocochlear reflex with disease duration, metabolic control and age at time of diagnosis. METHOD: A total of 101 children and adolescents were evaluated. They were divided into two groups: 50 with T1DM and 51 without the disease. The participants answered a structured questionnaire containing questions about auditory complaints and were evaluated for tonal audiometry, tympanometry, acoustic reflex, otoacoustic emission by distortion product to evaluate the inhibitory effect of medial olivocochlear reflex (MOC). RESULTS: The participants with T1DM presented changed AR (increased or absent) at all the frequencies in both ears (p < 0.05) when compared with the group without the disease. No differences were found between the DPOAE amplitudes of the individuals with and without T1DM, in both ears at all the frequencies. There were significant differences in the activation of the MOC reflex between the groups with and without T1DM, the participants with T1DM presented the absence of the inhibitory effect of the DPOAE in the right and left ears, in the frequencies of 4000 Hz (p = 0.035/0.002respectively) and 6000 Hz (p = 0.033/0.031 respectively) and 8000 Hz (p = 0.007/0.001 respectively) when compared to the healthy group. Significant differences were also observed between the groups with and without T1DM (p < 0.05) for self-reported complaints of tinitus, difficulties with the perception of speech when there was noise and distraction with noise. No association was found between the hearing complaints and the audiological measurements obtained and disease time, metabolic control and age at the time of diagnosis. CONCLUSION: The findings suggest the presence of early auditory dysfunction of the efferent pathway in patients with T1DM.

Analyzing the FFR: A tutorial for decoding the richness of auditory function.

The frequency-following response, or FFR, is a neurophysiological response to sound that precisely reflects the ongoing dynamics of sound. It can be used to study the integrity and malleability of neural encoding of sound across the lifespan. Sound processing in the brain can be impaired with pathology and enhanced through expertise. The FFR can index linguistic deprivation, autism, concussion, and reading impairment, and can reflect the impact of enrichment with short-term training, bilingualism, and musicianship. Because of this vast potential, interest in the FFR has grown considerably in the decade since our first tutorial. Despite its widespread adoption, there remains a gap in the current knowledge of its analytical potential. This tutorial aims to bridge this gap. Using recording methods we have employed for the last 20 + years, we have explored many analysis strategies. In this tutorial, we review what we have learned and what we think constitutes the most effective ways of capturing what the FFR can tell us. The tutorial covers FFR components (timing, fundamental frequency, harmonics) and factors that influence FFR (stimulus polarity, response averaging, and stimulus presentation/recording jitter). The spotlight is on FFR analyses, including ways to analyze FFR timing (peaks, autocorrelation, phase consistency, cross-phaseogram), magnitude (RMS, SNR, FFT), and fidelity (stimulus-response correlations, response-to-response correlations and response consistency). The wealth of information contained within an FFR recording brings us closer to understanding how the brain reconstructs our sonic world.

Why and how music can be used to rehabilitate and develop speech and language skills in hearing-impaired children.

This paper presents evidence for a strong connection between the development of speech and language skills and musical activities of children and adolescents with hearing impairment and/or cochlear implants. This conclusion is partially based on findings for typically hearing children and adolescents, showing better speech and language skills in children and adolescents with musical training, and importantly, showing increases of speech and language skills in children and adolescents taking part in musical training. Further, studies of hearing-impaired children show connections between musical skills, involvement in musical hobbies, and speech and language skills. Even though the field is still lacking large-scale randomised controlled trials on the effects of musical interventions on the speech and language skills of children and adolescents with hearing impairments and cochlear implants, the current evidence seems enough to urge speech therapists, music therapists, music teachers, parents, and children and adolescents with hearing impairments and/or cochlear implants to start using music for enhancing speech and language skills. For this reason, we give our recommendations on how to use music for language skill enhancement in this group.

Measuring temporal response properties of auditory nerve fibers in cochlear implant recipients.

Auditory nerve fibers' (ANFs) refractoriness and facilitation can be quantified in electrically evoked compound action potentials (ECAPs) recorded via neural response telemetry (NRT). Although facilitation has been observed in animals and human cochlear implant (CI) recipients, no study has modeled this in human CI users until now. In this study, recovery and facilitation effects at different masker and probe levels for three test electrodes (E6, E12 and E18) in 11 CI subjects were recorded. The ECAP recovery and facilitation were modeled by exponential functions and the same function used for +10 CL masker offset condition can be applied to all other masker offsets measurements. Goodness of fit was evaluated for the exponential functions. A significant effect of probe level was observed on a recovery time constant which highlights the importance of recording the recovery function at the maximum acceptable stimulus level. Facilitation time constant and amplitude showed no dependency on the probe level. However, facilitation was stronger for masker level at or around the threshold of the ECAP (T-ECAP). There was a positive correlation between facilitation magnitude and amplitude growth function (AGF) slope, which indicates that CI subjects with better peripheral neural survival have stronger facilitation.

Brainstem encoding of frequency-modulated sweeps is relevant to Mandarin concurrent-vowels identification for normal-hearing and hearing-impaired listeners.

F0 contours convey the primary information of lexical Tones for Mandarin Chinese, and the processing of time-varying F0 contours is important for Mandarin concurrent-vowels identification (MCVI). In this work, we examined the relationship between frequency modulation (FM) detection of auditory system and MCVI in both normal-hearing (NH) and hearing-impaired (HI) listeners. Three experiments were conducted with the same subjects to measure their MCVI, FM detection limen (FMDL), and frequency following responses (FFRs) evoked by FM sweeps, respectively. To ensure that F0 contour was the primary cue utilized, mean F0s and durations were equalized among all test vowels in the MCVI experiment. To simulate the pattern of F0 contours of Mandarin vowels, linearly FM sweeps were used as stimuli in the FMDL and FFRs experiments. The results confirmed that the performance of HI listeners was significantly worse than that of NH listeners in all of the three measurements. Besides, FFRs evoked by FM sweeps had significantly lower tracking accuracy than those evoked by steady tones only for HI listeners. The correlation analysis further revealed that any two of the three measured indices were significantly correlated when the effects of age and absolute threshold were partialed out (|r| ≥ 0.502, p ≤ 0.017). These results suggested an association between the poor performance of HI listeners in the MCVI task and their degraded auditory function on FM detection, and such a behavioral degradation has emerged in the phase-locking activity at the brainstem level.

Development and validation of the FrBio, an international French adaptation of the AzBio sentence lists.

Objectives: The goal of this work was to develop and normalise an international French version of the AzBio sentence test. Design: A corpus of 1000 sentences was generated. These sentences were recorded with four talkers and processed through a four-channel cochlear implant simulation. The mean intelligibility for each sentence achieved by 16 normal-hearing listeners was computed. The consecutively ordered 165 sentences from each talker rendering an average score of 85% were sequentially assigned to 33 lists of 20 sentences. All lists were presented to 30 normal-hearing and 25 hearing-impaired listeners in order to verify their equivalency. Thirty normal-hearing adults were also recruited to assess the test's psychometrics and define norms. Results: The results of the list equivalency validation study showed no significant differences in percent correct scores for 30 sentence lists. A binomial distribution model was used to estimate the 95% critical differences for each potential percentage score. Normalization data showed an average performance between 96% and 99% with a very low standard deviation. Conclusions: With a set of 30 lists, researchers and clinicians can use the FrBio to evaluate a large number of experimental conditions; changes in performance over time or across conditions can then be tracked.