Inner ear function in patients with obstructive sleep apnea.

OBJECTIVE: Because of their high metabolic activity and low-resting oxygen tension, the organs of the inner ear are vulnerable to hypoxia, a condition that occurs repetitively in obstructive sleep apnea-hypopnea syndrome (OSAHS). The present study aimed to investigate the inner ear function of patients with OSAHS. METHODS: A total of 58 patients with OSAHS (116 ears) and 20 adults without OSAHS were enrolled in the present study. The clinical features, such as air-conduction thresholds, auditory brainstem response (ABR, 11 times/s and 51 times/s stimulation rates), and distorted products otoacoustic emission (DPOAE), were evaluated and compared between these two groups. RESULTS: Air-conduction thresholds at 4 kHz and 8 kHz were higher in patients with OSAHS compared with controls (P < 0.001). At the rate of 11 times per second, biauricular wave I latencies and wave V latencies in the OSAHS group were longer than those in the control group (1.51 ± 0.13 vs. 1.33 ± 0.07 ms, P < 0.001; 5.65 ± 0.23 vs. 5.53 ± 0.23 ms, P = 0.0016). At the rate of 51 times per second, biauricular wave I latencies and wave V latencies in the OSAHS group were longer than those in the control group (1.64 ± 0.12 vs. 1.44 ± 0.06 ms, P = 0.0001; 5.92 ± 0.26 vs. 5.80 ± 0.18 ms, P = 0.0077). However, there was no significant difference in the wave I and wave V interval between these two groups (P = 0.10). DPOAE amplitude was significantly reduced in OSAHS patients, although no hearing loss was observed. CONCLUSION: High-frequency hearing loss was detected in adults with severe OSAHS, and wave I latencies and wave V latencies of ABR were prolonged.

Evidence for age-related cochlear synaptopathy in humans unconnected to speech-in-noise intelligibility deficits.

Cochlear synaptopathy (or the loss of primary auditory synapses) remains a subclinical condition of uncertain prevalence. Here, we investigate whether it affects humans and whether it contributes to suprathreshold speech-in-noise intelligibility deficits. For 94 human listeners with normal audiometry (aged 12-68 years; 64 women), we measured click-evoked auditory brainstem responses (ABRs), self-reported lifetime noise exposure, and speech reception thresholds for sentences (at 65 dB SPL) and words (at 50, 65 and 80 dB SPL) in steady-state and fluctuating maskers. Based on animal research, we assumed that the shallower the rate of growth of ABR wave-I amplitude versus level function, the higher the risk of suffering from synaptopathy. We found that wave-I growth rates decreased with increasing age but not with increasing noise exposure. Speech reception thresholds in noise were not correlated with wave-I growth rates and mean speech reception thresholds were not statistically different for two subgroups of participants (N = 14) with matched audiograms (up to 12 kHz) but different wave-I growth rates. Altogether, the data are consistent with the existence of age-related but not noise-related synaptopathy. In addition, the data dispute the notion that synaptopathy contributes to suprathreshold speech-in-noise intelligibility deficits.

Comparison of Frequency Transposition and Frequency Compression for People With Extensive Dead Regions in the Cochlea.

The objective was to determine the effects of two frequency-lowering algorithms (frequency transposition, FT, and frequency compression, FC) on audibility, speech identification, and subjective benefit, for people with high-frequency hearing loss and extensive dead regions (DRs) in the cochlea. A single-blind randomized crossover design was used. FT and FC were compared with each other and with a control condition (denoted 'Control') without frequency lowering, using hearing aids that were otherwise identical. Data were collected after at least 6 weeks of experience with a condition. Outcome measures were audibility, scores for consonant identification, scores for word-final /s, z/ detection ( S test), sentence-in-noise intelligibility, and a questionnaire assessing self-perceived benefit (Spatial and Qualities of Hearing Scale). Ten adults with steeply sloping high-frequency hearing loss and extensive DRs were tested. FT and FC improved the audibility of some high-frequency sounds for 7 and 9 participants out of 10, respectively. At the group level, performance for FT and FC did not differ significantly from that for Control for any of the outcome measures. However, the pattern of consonant confusions varied across conditions. Bayesian analysis of the confusion matrices revealed a trend for FT to lead to more consistent error patterns than FC and Control. Thus, FT may have the potential to give greater benefit than Control or FC following extended experience or training.

Extended High-Frequency Smartphone Audiometry: Validity and Reliability.

BACKGROUND: Extended high-frequency (EHF) audiometry (8-16 kHz) has an important role in audiological assessments such as ototoxicity monitoring, and for speech recognition and localization. Accurate and reliable EHF testing with smartphone technologies has the potential to provide more affordable and accessible hearing-care services, especially in underserved contexts. PURPOSE: To determine the accuracy and test-retest reliability of EHF audiometry with a smartphone application, using calibrated headphones. RESEARCH DESIGN: Air-conduction thresholds (8-16 kHz) and test-retest reproducibility, recorded with conventional audiometry (CA) and smartphone audiometry (SA), using audiometric (Sennheiser HDA 300 circumaural) and nonstandard audiometric (Sennheiser HD202 II supra-aural) headphones, were compared in a repeated-measures design. STUDY SAMPLE: A total of 61 participants (122 ears) were included in the study. Of these, 24 were adults attending a tuberculosis clinic (mean age = 36.8, standard deviation [SD] = 14.2 yr; 48% female) and 37 were adolescents and young adults recruited from a prospective students program (mean age = 17.6, SD = 3.2 yr; 76% female). Of these, 22.3% (n = 326) of EHF thresholds were ≥25 dB HL. DATA ANALYSIS: Threshold comparisons were made between CA and SA, with audiometric headphones and nonstandard audiometric headphones. A paired samples t-test was used for comparison of threshold correspondence between conventional and smartphone thresholds, and test-retest reproducibility of smartphone thresholds. RESULTS: Conventional thresholds corresponded with smartphone thresholds at the lowest intensity (10 dB HL), using audiometric and nonstandard audiometric headphones in 59.4% and 57.6% of cases, respectively. Conventional thresholds (exceeding 10 dB HL) corresponded within 10 dB or less, with smartphone thresholds in 82.9% of cases using audiometric headphones and 84.1% of cases using nonstandard audiometric headphones. There was no significant difference between CA and SA, using audiometric headphones across all frequencies (p > 0.05). Test-retest comparison also showed no significant differences between conditions (p > 0.05). Smartphone test-retest thresholds corresponded within 10 dB or less in 86.7% and 93.4% of cases using audiometric and nonstandard audiometric headphones, respectively. CONCLUSIONS: EHF smartphone testing with calibrated headphones can provide an accurate and reliable option for affordable mobile audiometry. The validity of EHF smartphone testing outside a sound booth as a cost-effective and readily available option to detect high-frequency hearing loss in community-based settings should be established.

Investigation of high-frequency hearing loss and outer hair cell function of the cochlea in patients with psoriasis: a case-control study.

The inner ear can be the target of autoimmune attacks, and sensorineural hearing loss can occur as a complication in various non-organ-specific autoimmune diseases. The aim of this study was to compare cochlear functions and hearing evaluation in patients with psoriasis and controls. In total, 29 patients with psoriasis and 30 healthy controls (HCs) were included in the study. Pure-tone audiometry at 250, 500, 1000, 2000, 4000, 8000, 10 000, 12 000, 14 000 and 16 000 Hz was performed for patients as HCs, as were immittance measures including tympanometry, acoustic reflex and otoacoustic emission testing. There were statistically significant (P < 0.05) differences between patients and HCs for pure-tone thresholds at high frequencies, and for distortion product otoacoustic emission (DPOAE) responses and signal : noise ratio at all frequencies. In our study, based on DPOAE and audiological findings, there was damage to the outer hair cells of the cochlea, resulting in high-frequency hearing loss in patients with psoriasis.

Vocal Biomarkers of Mild-to-Moderate Hearing Loss in Children and Adults: Voiceless Sibilants.

Purpose: The purpose of this study was to determine if an objective measure of speech production could serve as a vocal biomarker for the effects of high-frequency hearing loss on speech perception. It was hypothesized that production of voiceless sibilants is governed sufficiently by auditory feedback that high-frequency hearing loss results in subtle but significant shifts in the spectral characteristics of these sibilants. Method: Sibilant production was examined in individuals with mild to moderately severe congenital (22 children; 8-17 years old) and acquired (23 adults; 55-80 years old) hearing losses. Measures of hearing level (pure-tone average thresholds at 4 and 8 kHz), speech perception (detection of nonsense words within sentences), and speech production (spectral center of gravity [COG] for /s/ and /ʃ/) were obtained in unaided and aided conditions. Results: For both children and adults, detection of nonsense words increased significantly as hearing thresholds improved. Spectral COG for /ʃ/ was unaffected by hearing loss in both listening conditions, whereas the spectral COG for /s/ significantly decreased as high-frequency hearing loss increased. The distance in spectral COG between /s/ and /ʃ/ decreased significantly with increasing hearing level. COG distance significantly predicted nonsense-word detection in children but not in adults. Conclusions: At least one aspect of speech production (voiceless sibilants) is measurably affected by high-frequency hearing loss and is related to speech perception in children. Speech production did not predict speech perception in adults, suggesting a more complex relationship between auditory feedback and feedforward mechanisms with age. Even so, these results suggest that this vocal biomarker may be useful for identifying the presence of high-frequency hearing loss in adults and children and for predicting the impact of hearing loss in children.

Extended high-frequency hearing loss following the first episode of otitis media.

OBJECTIVES/HYPOTHESIS: Otitis media has been associated with several auditory and developmental sequelae. Here, the results of auditory tests were evaluated in patients who had a first episode of unilateral otitis media and compared with the contralateral healthy ear. STUDY DESIGN: Cohort study. METHODS: This study was undertaken from 2015 to 2016, with a follow-up period of 6 months. RESULTS: A total of 41 patients who had been diagnosed with unilateral acute otitis media were selected. Standard (250 Hz-8 kHz) and extended high-frequency (8 kHz-16 kHz) audiometry was performed within 5 days of the beginning of the clinical symptoms, and then in defined time frames for a period of 6 months. The results of the contralateral healthy ears were used as individual controls. After closure of the initial air-bone gap, the results of the standard audiometry did not demonstrate significant differences in the thresholds of diseased ears compared with controls. A significant elevation of the mean extended high-frequency thresholds in the ears affected by otitis media was observed at the first and subsequent appointments within the 6-month follow-up period. Diseased ears from patients who experienced tinnitus during the 6-month follow-up period had significantly higher thresholds in the extended high frequencies than diseased ears from patients without residual tinnitus. CONCLUSIONS: These results suggest that the first episode of otitis media may lead to persistent elevation of the mean thresholds of extended high-frequencies, whereas persistent tinnitus after 6 months of the acute infection is associated with more severe hearing loss. LEVEL OF EVIDENCE: 2b Laryngoscope, 128:2879-2884, 2018.

Evaluation of a Frequency-Lowering Algorithm for Adults With High-Frequency Hearing Loss.

The objective was to determine the effects of a frequency-lowering algorithm (frequency composition, Fcomp) on consonant identification, word-final /s, z/ detection, the intelligibility of sentences in noise, and subjective benefit, for people with high-frequency hearing loss, including people with dead regions (DRs) in the cochlea. A single-blind randomized crossover design was used. Performance with Bernafon Acriva 9 hearing aids was compared with Fcomp off and Fcomp on. Participants wore the hearing aids in each condition in a counterbalanced order. Data were collected after at least 8 weeks of experience with a condition. Outcome measures were audibility, scores from the speech perception tests, and scores from a questionnaire comparing self-perceived hearing ability with Fcomp off and Fcomp on. Ten adults with mild to severe high-frequency hearing loss (seven with extensive DRs, one with patchy or restricted DRs, and two with no DR) were tested. Fcomp improved the audibility of high-frequency sounds for 6 out of 10 participants. There was no overall effect of Fcomp on consonant identification, but the pattern of consonant confusions varied across conditions and participants. For word-final /s, z/ detection, performance was significantly better with Fcomp on than with Fcomp off. Questionnaire scores showed no differences between conditions. In summary, Fcomp improved word-final /s, z/ detection. No benefit was found for the other measures.

Evaluation of Maximal Speech Intelligibility With Vibrant Soundbridge in Patients With Sensorineural Hearing Loss.

OBJECTIVE: The study investigated improvements in maximal speech intelligibility after Vibrant Soundbridge (VSB) implantation and analyzed the effect of the hearing loss pattern on maximal speech intelligibility represented by a phonetically balanced word score (PBmax). The effect of middle ear implants on PBmax has not been evaluated yet. STUDY DESIGN: Study. SETTING: Tertiary academic medical center. PATIENTS/INTERVENTIONS: Sixty patients who underwent VSB from December 2011 to January 2016 were retrospectively reviewed. All the patients had hearing aids preoperatively. MAIN OUTCOME MEASURES: Pure-tone and speech audiometry were checked with and without hearing aids and then with the VSB. The patients were divided into two groups: flat and down-sloping type of hearing loss. PBmax score was evaluated at the most comfortable listening level before and after VSB implantation and compared with scores with/without HA. RESULTS: PBmax for both conventional HA and VSB were significantly higher compared with the unaided condition. The improvement in speech recognition was significantly better using VSB than using HA (p = 0.003). However, there was no significant difference in the improvement provided by VSB and HA in patients with a flat hearing loss. Patients with a down-sloping audiogram showed significantly better improvement with VSB than with HA (p = 0.003). Moreover, patients with greater preoperative high-frequency hearing loss had greater improvement in PBmax after VSB implantation. CONCLUSION: Speech intelligibility can be significantly improved by VSB implantation, especially in patients with a down-sloping hearing loss. This finding can help select patients who will benefit most from VSB implantation.

Declining and fluctuating prevalence values of hearing impairment in 18-year old Swedish men during three decades.

OBJECTIVE: To analyze time trends in prevalence of hearing impairment in almost complete birth cohorts of 18-year old Swedish men from 1970s up to 2010. STUDY GROUPS: Before 1999, all 18-year old men, in Sweden, were called for a compulsory conscription examination. In 1971-1999, the participation rate in audiometry was 73-95%. After 1999, when exemption from conscription was allowed, the participation rate gradually declined to 52% in 2004. Samples with participation rates below 50% (2005-2010) were considered non-representative and excluded from the analyses. RESULTS: High-frequency hearing impairments (HFHI) 35-40 dB HL and ≥45 dB HL showed a decreasing trend over the observed period, from a prevalence of 2.9% (35-40 dB HL) and 3.8% (≥45 dB HL) respectively in 1971 to 1.4% and 1.1% respectively in 2004. HFHI 25-30 dB HL, showed slow variations over time and decreased from 8.5% in 1971 to 3.2% in 1981 followed by an increase to 10.4% in 1992. After that year there was a decrease to 5.2% in 2004. The slow fluctuations affected only HFHI 25-30 dB HL, mainly at 6 kHz. The left ear was more affected than the right ear. CONCLUSIONS: The most important observation was a decrease of HFHI 35-40 dB HL by 52% percent and of HFHI ≥45 dB HL by 71% between the years 1971 and 2004. The prevalence of HFHI 25-30 dB HL in young Swedish males fluctuated over a period of 33 years. Possible reasons for these trends and variations are discussed.

Laboratory evaluation of an optimised internet-based speech-in-noise test for occupational high-frequency hearing loss screening: Occupational Earcheck.

OBJECTIVE: The "Occupational Earcheck" (OEC) is a Dutch online self-screening speech-in-noise test developed for the detection of occupational high-frequency hearing loss (HFHL). This study evaluates an optimised version of the test and determines the most appropriate masking noise. DESIGN: The original OEC was improved by homogenisation of the speech material, and shortening the test. A laboratory-based cross-sectional study was performed in which the optimised OEC in five alternative masking noise conditions was evaluated. STUDY SAMPLE: The study was conducted on 18 normal-hearing (NH) adults, and 15 middle-aged listeners with HFHL. RESULTS: The OEC in a low-pass (LP) filtered stationary background noise (test version LP 3: with a cut-off frequency of 1.6 kHz, and a noise floor of -12 dB) was the most accurate version tested. The test showed a reasonable sensitivity (93%), and specificity (94%) and test reliability (intra-class correlation coefficient: 0.84, mean within-subject standard deviation: 1.5 dB SNR, slope of psychometric function: 13.1%/dB SNR). CONCLUSIONS: The improved OEC, with homogenous word material in a LP filtered noise, appears to be suitable for the discrimination between younger NH listeners and older listeners with HFHL. The appropriateness of the OEC for screening purposes in an occupational setting will be studied further.

Hearing Loss and Age-Induced Changes in the Central Auditory System Measured by the P3 Response to Small Changes in Frequency.

BACKGROUND: Recent behavioral studies have suggested that individuals with sloping audiograms exhibit localized improvements in frequency discrimination in the frequency region near the drop in hearing. Auditory-evoked potentials may provide evidence of such cortical plasticity and reorganization of frequency maps. PURPOSE: The objective of this study was to evaluate electrophysiological evidence of cortical plasticity related to cortical frequency representation and discrimination abilities in older individuals with high-frequency sensorineural hearing loss (SNHL). It was hypothesized that the P3 response in this group would show evidence of physiological reorganization of frequency maps and enhanced neural representation at the edge of their high-frequency loss due to their restricted SNHL. RESEARCH DESIGN: The P3 auditory event-related potential in response to small frequency changes was recorded in a repeated measures design using an oddball paradigm that presented upward and downward frequency changes of 2%, 5%, and 20% to three groups of listeners. STUDY SAMPLE: P3 recordings from a group of seven older individuals with a restricted sloping hearing loss >1000 or 2000 Hz was compared to two control groups of younger (n = 7) and older (n = 7) individuals with normal hearing/borderline normal hearing through 4000 Hz. DATA COLLECTION AND ANALYSIS: The auditory P3 was recorded using an oddball paradigm (80%/20%) with the standard tone at the highest frequency of normal hearing in the hearing-impaired participants, also known as the edge frequency (EF). EFs were either 1000 or 2000 Hz for all participants. The target tones represented upward and downward frequency changes of 2%, 5%, and 20% from the standard tones of either 1000 or 2000 Hz. Waveforms were recorded using a two-channel clinical-evoked potential system. Latency and amplitude of the P300 peak were analyzed across groups for the three frequency conditions using repeated measures analysis of variance. RESULTS: The results of this study suggest that the P3 response can be elicited by frequency changes as small as 2-5%. P3 responses at the EF of hearing loss were present and larger in amplitude for more participants with a sloping hearing loss compared to age-matched normal-hearing peers tested at the same frequencies. As a result, the older participants with sloping hearing losses had P3 responses more similar to the younger normal-hearing participants than their age-matched peers with normal hearing. CONCLUSIONS: These preliminary results partially support the idea of enhanced cortical representation of frequency at the EF of localized SNHL in older adults that is not purely due to age.

The Association Between Age-Related Hearing Impairment and Metabolic Syndrome in Korean Women: 5-Year Follow-Up Observational Study.

BACKGROUND: Although several observational studies showed a relationship between various conditions of metabolic syndrome (MetS) and hearing threshold, there are no studies about longitudinal audiometric results related MetS. The aim of this study was to investigate the association between MetS and age-related hearing impairment (ARHI) through a large, average 5-year longitudinal follow-up, clinical comparative analysis. MATERIALS AND METHODS: We recruited 1381 women older than 50 years who were enrolled in 2007 and reevaluated in 2012. They had normal or symmetrical sensorineural hearing loss. For the evaluation of the independent impact of MetS on hearing, multivariate analysis was used. RESULTS: The average follow-up period was 5.0 ± 0.2 years. Subjects with MetS had higher hearing thresholds than subjects without MetS. The loss in high-frequency hearing (≥2000 Hz) progressed more rapidly in women with MetS over a 5-year period. CONCLUSION: Our analysis using longitudinal and large data revealed that MetS is associated with ARHI in women 50 years and older. High-frequency hearing loss tended to be greater in women with MetS than in those without MetS at the 5-year follow-up. Therefore, older women with MetS should be followed up closely for hearing evaluation.

Prevalence of Hearing Loss in Teachers of Singing and Voice Students.

OBJECTIVES: Singers and voice teachers are exposed to a range of noise levels during a normal working day. This study aimed to assess the hearing thresholds in a large sample of generally healthy professional voice teachers and voice students to determine the prevalence of hearing loss in this population. STUDY DESIGN: A cross-sectional study was carried out. METHODS: Voice teachers and vocal students had the option to volunteer for a hearing screening of six standard frequencies in a quiet room with the Shoebox audiometer (Clearwater Clinical Limited) and to fill out a brief survey. Data were analyzed for the prevalence and severity of hearing loss in teachers and students based on several parameters assessed in the surveys. All data were analyzed using Microsoft Excel (Microsoft Corp.) and SPSS Statistics Software (IBM Corp.). RESULTS: A total of 158 participants were included: 58 self-identified as voice teachers, 106 as voice students, and 6 as both. The 6 participants who identified as both, were included in both categories for statistical purposes. Of the 158 participants, 36 had some level of hearing loss: 51.7% of voice teachers had hearing loss, and 7.5% of voice students had hearing loss. Several parameters of noise exposure were found to positively correlate with hearing loss and tinnitus (P < 0.05). Years as a voice teacher and age were both predictors of hearing loss (P < 0.05). CONCLUSIONS: Hearing loss in a cohort of voice teachers appears to be more prevalent and severe than previously thought. There is a significant association between years teaching and hearing loss. Raising awareness in this population may prompt teachers and students to adopt strategies to protect their hearing.

Prevalence of Hearing Loss Among a Representative Sample of Canadian Children and Adolescents, 3 to 19 Years of Age.

OBJECTIVES: There are no nationally representative hearing loss (HL) prevalence data available for Canadian youth using direct measurements. The present study objectives were to estimate national prevalence of HL using audiometric pure-tone thresholds (0.5 to 8 kHz) and or distortion product otoacoustic emissions (DPOAEs) for children and adolescents, aged 3 to 19 years. DESIGN: This cross-sectional population-based study presents findings from the 2012/2013 Canadian Health Measures Survey, entailing an in-person household interview and hearing measurements conducted in a mobile examination clinic. The initial study sample included 2591 participants, aged 3 to 19 years, representing 6.5 million Canadians (3.3 million males). After exclusions, subsamples consisted of 2434 participants, aged 3 to 19 years and 1879 participants, aged 6 to 19 years, with valid audiometric results. Eligible participants underwent otoscopic examination, tympanometry, DPOAE, and audiometry. HL was defined as a pure-tone average >20 dB for 6- to 18-year olds and ≥26 dB for 19-year olds, for one or more of the following: four-frequency (0.5, 1, 2, and 4 kHz) pure-tone average, high-frequency (3, 4, 6, and 8 kHz) pure-tone average, and low-frequency (0.5, 1, and 2 kHz) pure-tone average. Mild HL was defined as >20 to 40 dB (6- to 18-year olds) and ≥26 to 40 dB (19-year olds). Moderate or worse HL was defined as >40 dB (6- to 19-year olds). HL in 3- to 5-year olds (n = 555) was defined as absent DPOAEs as audiometry was not conducted. Self-reported HL was evaluated using the Health Utilities Index Mark 3 hearing questions. RESULTS: The primary study outcome indicates that 7.7% of Canadian youth, aged 6 to 19, had any HL, for one or more pure-tone average. Four-frequency pure-tone average and high-frequency pure-tone average HL prevalence was 4.7 and 6.0%, respectively, whereas 5.8% had a low-frequency pure-tone average HL. Significantly more children/adolescents had unilateral HL. Mild HL was significantly more common than moderate or worse HL for each pure-tone average. Among Canadians, aged 6 to 19, less than 2.2% had sensorineural HL. Among Canadians, aged 3 to 19, less than 3.5% had conductive HL. Absent DPOAEs were found in 7.1% of 3- to 5-year olds, and in 3.4% of 6- to 19-year olds. Among participants eligible for the hearing evaluation and excluding missing data cases (n = 2575), 17.0% had excessive or impacted pus/wax in one or both ears. Self-reported HL in Canadians, aged 6 to 19, was 0.6 E% and 65.3% (aged 3 to 19) reported never having had their hearing tested. E indicates that a high sampling variability is associated with the estimate (coefficient of variation between 16.6% and 33.3%) and should be interpreted with caution. CONCLUSIONS: This study provides the first estimates of audiometrically measured HL prevalence among Canadian children and adolescents. A larger proportion of youth have measured HL than was previously reported using self-report surveys, indicating that screening using self-report or proxy may not be effective in identifying individuals with mild HL. Results may underestimate the true prevalence of HL due to the large number excluded and the presentation of impacted or excessive earwax or pus, precluding an accurate or complete hearing evaluation. The majority of 3- to 5-year olds with absent DPOAEs likely had conductive HL. Nonetheless, this type of HL which can be asymptomatic, may become permanent if left untreated. Future research will benefit from analyses, which includes the slight HL category, for which there is growing support, and from studies that identify factors contributing to HL in this population.

Impaired auditory processing and altered structure of the endbulb of Held synapse in mice lacking the GluA3 subunit of AMPA receptors.

AMPA glutamate receptor complexes with fast kinetics conferred by subunits like GluA3 and GluA4 are essential for temporal precision of synaptic transmission. The specific role of GluA3 in auditory processing and experience related changes in the auditory brainstem remain unknown. We investigated the role of the GluA3 in auditory processing by using wild type (WT) and GluA3 knockout (GluA3-KO) mice. We recorded auditory brainstem responses (ABR) to assess auditory function and used electron microscopy to evaluate the ultrastructure of the auditory nerve synapse on bushy cells (AN-BC synapse). Since labeling for GluA3 subunit increases on auditory nerve synapses within the cochlear nucleus in response to transient sound reduction, we investigated the role of GluA3 in experience-dependent changes in auditory processing. We induced transient sound reduction by plugging one ear and evaluated ABR threshold and peak amplitude recovery for up to 60 days after ear plug removal in WT and GluA3-KO mice. We found that the deletion of GluA3 leads to impaired auditory signaling that is reflected in decreased ABR peak amplitudes, an increased latency of peak 2, early onset hearing loss and reduced numbers and sizes of postsynaptic densities (PSDs) of AN-BC synapses. Additionally, the lack of GluA3 hampers ABR threshold recovery after transient ear plugging. We conclude that GluA3 is required for normal auditory signaling, normal ultrastructure of AN-BC synapses in the cochlear nucleus and normal experience-dependent changes in auditory processing after transient sound reduction.

Speech perception and quality of life of open-fit hearing aid users.

OBJECTIVE: To relate the performance of individuals with hearing loss at high frequencies in speech perception with the quality of life before and after the fitting of an open-fit hearing aid (HA). METHODS: The WHOQOL-BREF had been used before the fitting and 90 days after the use of HA. The Hearing in Noise Test (HINT) had been conducted in two phases: (1) at the time of fitting without an HA (situation A) and with an HA (situation B); (2) with an HA 90 days after fitting (situation C). STUDY SAMPLE: Thirty subjects with sensorineural hearing loss at high frequencies. RESULTS: By using an analysis of variance and the Tukey's test comparing the three HINT situations in quiet and noisy environments, an improvement has been observed after the HA fitting. The results of the WHOQOL-BREF have showed an improvement in the quality of life after the HA fitting (paired t-test). The relationship between speech perception and quality of life before the HA fitting indicated a significant relationship between speech recognition in noisy environments and in the domain of social relations after the HA fitting (Pearson's correlation coefficient). CONCLUSIONS: The auditory stimulation has improved speech perception and the quality of life of individuals.

Speech perception and quality of life of open-fit hearing aid users

ABSTRACT Objective To relate the performance of individuals with hearing loss at high frequencies in speech perception with the quality of life before and after the fitting of an open-fit hearing aid (HA). Methods The WHOQOL-BREF had been used before the fitting and 90 days after the use of HA. The Hearing in Noise Test (HINT) had been conducted in two phases: (1) at the time of fitting without an HA (situation A) and with an HA (situation B); (2) with an HA 90 days after fitting (situation C). Study Sample Thirty subjects with sensorineural hearing loss at high frequencies. Results By using an analysis of variance and the Tukey’s test comparing the three HINT situations in quiet and noisy environments, an improvement has been observed after the HA fitting. The results of the WHOQOL-BREF have showed an improvement in the quality of life after the HA fitting (paired t-test). The relationship between speech perception and quality of life before the HA fitting indicated a significant relationship between speech recognition in noisy environments and in the domain of social relations after the HA fitting (Pearson’s correlation coefficient). Conclusions The auditory stimulation has improved speech perception and the quality of life of individuals.

Late onset and high-frequency dominant hearing loss in a family with MYH9 disorder.

MYH9 disorder is a rare autosomal-dominant disorder. We previously reported that it is caused by mutations in the gene for nonmuscle myosin heavy chain IIA (NMMHC-IIA). MYH9 disorder causes congenital macrothrombocytopenia accompanied by progressive sensorineural hearing loss, nephropathy, and cataract. However, there are few reports that describe the audiological features of MYH9 disorder. The objective of this study was to characterize auditory and other phenotypes of patients with MYH9 disorder. We examined nine subjects from one Japanese family. Audiological, ophthalmological, hematological, and imaging examinations were used to assess clinical features. We carried out genetic analysis of the causative gene, MYH9. Five subjects exhibited macrothrombocytopenia and neutrophil cytoplasmic inclusion bodies. Immunofluorescence analysis of neutrophil NMMHC-IIA revealed abnormal type II localization. Two subjects had high-frequency dominant hearing loss, which was adult onset and progressive. Only one subject had cataract. MYH9 sequencing analysis of all thrombocytopenic subjects revealed a heterozygous c.4270G>A mutation in exon 30 (p.D1424N). We identified five patients with MYH9 disorder from the family. The hearing impairment associated with MYH9 disorder in this family was characterized as adult onset, progressive, and high-frequency dominant. Hematological manifestations of MYH9 disorder show complete penetrance, whereas extra-hematological manifestations show incomplete penetrance and variable expressivity in this family.