Distortion Product Otoacoustic Emissions Research Articles

The Effects of Memantine on Cisplatin-induced Ototoxicity.

We aimed to investigate electrophysiologically and histopathologically, the protective effects of intratympanic memantine, an N-methyl-D-aspartate receptor antagonist, on ototoxicity caused by cisplatin, an anti-neoplastic agent used in many types of cancer. Thirty-seven guinea pigs with a normal auditory function were randomly allocated to group 1 (Cisplatin; n=8), group 2 (Memantine; n=8), group 3 (Cisplatin+Memantine; n=8), group 4 (Cisplatin+Physiological Serum [PS]; n=8), and group 5 (Control; n=5). Auditory assessments were conducted using distortion product otoacoustic emissions (DPOAE) within a frequency range of 1-32 kHz, and auditory brainstem responses (ABR) within 8-32 kHz. A single dose of cisplatin (12 mg/kg) was administered intraperitoneally, followed by intratympanic administration of 0.2 mL of either memantine or PS to both ears at least half an hour before cisplatin administration. Subsequent auditory evaluations were conducted 72 h after cisplatin administration. Histopathological analyses were performed using light microscopy of the right ear and scanning electron microscopy (SEM) of the left ear. Auditory evaluations conducted before and after treatment revealed significant findings. Specifically, within groups 3 and 4, ABR thresholds were elevated at all frequencies (p=0.00), whereas the DPOAE signal-to-noise ratios were reduced at frequencies of 8, 12, 16, and 24 kHz (p=0.001, p=0.01, p=0.01, and p=0.00, respectively). Histopathologically, both light microscopy and SEM revealed that the cisplatin+memantine group exhibited fewer hair cells and nuclear degeneration in the spiral ganglion than the cisplatin and cisplatin+PS groups. Additionally, the stria vascularis thickness was greater in the cisplatin+memantine group than in cisplatin and cisplatin+PS groups. Despite the negative electrophysiological findings, the histopathological outcomes suggest that intratympanic memantine may have a potential protective effect against cisplatin-induced ototoxicity. However, further investigations are warranted to corroborate these findings and elucidate the underlying mechanisms of action of memantine.

Resistance to age-related hearing loss in the echolocating big brown bat (Eptesicus fuscus).

Hearing mediates many behaviours critical for survival in echolocating bats, including foraging and navigation. Although most mammals are susceptible to progressive age-related hearing loss, the evolution of biosonar, which requires the ability to hear low-intensity echoes from outgoing sonar signals, may have selected against the development of hearing deficits in bats. Many echolocating bats exhibit exceptional longevity and rely on acoustic behaviours for survival to old age; however, relatively little is known about the ageing bat auditory system. In this study, we used DNA methylation to estimate the ages of wild-caught big brown bats (Eptesicus fuscus) and measured hearing sensitivity in young and ageing bats using auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We found no evidence for hearing deficits in bats up to 12.5 years of age, demonstrated by comparable thresholds and similar ABR and DPOAE amplitudes across age groups. We additionally found no significant histological evidence for cochlear ageing, with similar hair cell counts, afferent and efferent innervation patterns in young and ageing bats. Here, we demonstrate that big brown bats show minimal evidence for age-related hearing loss and therefore represent informative models for investigating mechanisms that may preserve hearing function over a long lifetime.

MYH1 deficiency disrupts outer hair cell electromotility, resulting in hearing loss.

Myh1 is a mouse deafness gene with an unknown function in the auditory system. Hearing loss in Myh1-knockout mice is characterized by an elevated threshold for the auditory brainstem response and the absence of a threshold for distortion product otoacoustic emission. Here, we investigated the role of MYH1 in outer hair cells (OHCs), crucial structures in the organ of Corti responsible for regulating cochlear amplification. Direct whole-cell voltage-clamp recordings of OHCs revealed that prestin activity was lower in Myh1-knockout mice than in wild-type mice, indicating abnormal OHC electromotility. We analyzed whole-exome sequencing data from 437 patients with hearing loss of unknown genetic causes and identified biallelic missense variants of MYH1 in five unrelated families. Hearing loss in individuals harboring biallelic MYH1 variants was non-progressive, with an onset ranging from congenital to childhood. Three of five individuals with MYH1 variants displayed osteopenia. Structural prediction by AlphaFold2 followed by molecular dynamic simulations revealed that the identified variants presented structural abnormalities compared with wild-type MYH1. In a heterogeneous overexpression system, MYH1 variants, particularly those in the head domain, abolished MYH1 functions, such as by increasing prestin activity and modulating the membrane traction force. Overall, our findings suggest an essential function of MYH1 in OHCs, as observed in Myh1-deficient mice, and provide genetic evidence linking biallelic MYH1 variants to autosomal recessive hearing loss in humans.

Beyond the cochlea: exploring the multifaceted nature of hearing loss in primary mitochondrial diseases

Abstract Primary mitochondrial diseases, with diverse systemic manifestations, often present with auditory impairments due to mitochondrial dysfunction. This study provides an in-depth exploration of auditory deficits in primary mitochondrial diseases, highlighting the impact of various pathogenic variants on both cochlea and neural/central auditory functions. An observational study involving 72 adults with primary mitochondrial diseases was conducted. Participants underwent extensive audiological evaluations including Pure-Tone Audiometry, Tympanometry, Acoustic Reflex Thresholds, Quick Speech-in-Noise Test, Listening in Spatialized Noise-Sentences test, Auditory-evoked Brainstem Responses, and Distortion Product Otoacoustic Emissions. Multivariate Analysis of Covariance and logistic regression analyses assessed the influence of various pathogenic DNA variants, accounting for age, cognitive status via the Montreal Cognitive Assessment, and disease severity through the Newcastle Mitochondrial Disease Adult Scale. Participants with the pathogenic m.3243A>G/T variants (m.3243A>G n=40; m.3243A>T n=1) exhibited significant elevations in Pure-Tone Audiometry thresholds, especially at high frequencies, suggesting cochlea involvement. Notably, the Listening in Spatialized Noise-Sentences test showed significant spatial processing deficits in the m.3243A>G/T group, possibly indicating a unique mutation-specific impact on central auditory processing. Auditory-evoked Brainstem Responses results highlighted a higher likelihood of auditory brainstem response abnormalities in this group, further substantiating neural/central auditory pathway involvement. This study emphasises the heterogeneous nature of hearing impairment in primary mitochondrial diseases, with a genotype-phenotype correlation, particularly in the m.3243A>G/T group. These insights advocate for personalised, genotype-specific auditory assessments and targeted management strategies. Conventional hearing aids and cochlear implants are ineffective for those with central auditory dysfunctions related to mitochondrial mutations. There is an urgent need for innovative rehabilitation strategies catering for both cochlear and neural/central auditory pathways.

The Effect of Thymoquinone on Acoustic Trauma-Induced Hearing Loss in Rats.

Background The aim of this study was to investigate the protective effect of thymoquinone, an antioxidant, on hearing loss induced by acoustic trauma in rats. Material and methods This study included 32 Wistar Albino rats divided into four groups: control, acoustic trauma, thymoquinone + acoustic trauma, and thymoquinone only, with eight rats per group. The control group received 0.5 mL of corn oil intraperitoneally for 10 days. The acoustic trauma group was exposed to 100 dB white noise at 4 kHz for 16 hours. The thymoquinone + acoustic trauma group received thymoquinone (10 mg/kg) intraperitoneally for two days before acoustic trauma and eight days after acoustic trauma. The thymoquinone only group received thymoquinone (10 mg/kg) for 10 days. Distortion product otoacoustic emissions (DPOAEs) were measured before and after treatments on days 1, 4, and 10. Results In the control group, DPOAE measurements showed no significant change over the study period. The acoustic trauma group exhibited a significant decrease in DPOAE on the first day after trauma, followed by some recovery. The thymoquinone + acoustic trauma group showed no significant decrease in DPOAE on the first day post-trauma, suggesting a protective effect. The thymoquinone only group also indicated no significant change in DPOAE measurements, suggesting that thymoquinone alone did not affect hearing function. Conclusion Thymoquinone demonstrated a protective effect against acoustic trauma-induced hearing loss in rats, as evidenced by stable DPOAE measurements post-trauma. These findings suggest that thymoquinone may help preserve hearing function by reducing oxidative stress in the cochlea. Further studies are needed to confirm these results in humans and optimize dosage and treatment protocols.

3T-3D FLAIR MRI in Menière's disease: associated profiles with clinical symptoms and electroacoustic characteristics.

Diagnosis of Menière's disease relies on clinical symptoms. Injected 3T MRI can show endolymphatic hydrops (EH), but correlation with the clinical status of MD, (probable -PMD or definite-DMD) remains doubtful. We revealed endolymphatic pressure disruption through functional exploration and verified if it was associated with an EH through MRI. We prospectively analyzed 3D3T FLAIR MRI of DMD and PMD patients. All of them underwent electrocochleography (EcoG), distortion-product otoacoustic emissions (DPOAEs), and videonystagmograhy (VNG). Amplitudes of summating potential (SP) and cochlear nerve action potential (AP) were measured on EcoG. DPOAE-phase was collected at 1kHz for the 2f1-f2 DPOAE between sitting and laying position. A SP/AP ≥ 40% and a DPOAE phase-shift > 40° revealed pressure disruption. 39 patients (25 women, 53 y.o. 20-78), were included, with 32 DMD ears and 11 PMD ears. MRI was performed in a median of 21 days [0; 68] from the MD incident. Audiovestibular exploration took place 41 days after the crisis [0;83]. MRI revealed an EH in 71.9% and 27.2% of DMD and PMD, respectively. When combining functional explorations and MRI, testing was positive in 97% for DMD and 82% for PMD. When abnormal (59%), VNG mainly showed hyporeflexia in the diseased ear. In patients suffering from DMD or PMD, with endolymphatic pressure disturbances confirmed by combined DPOAE-phase and EcoG, 3T 3D MRI reveals EH mostly in DMD but rarely in PMD. This seems to confirm that disturbance of endolymphatic pressure precedes EH.

Changes in Auditory Performance Following a Virtual Reality Music Concert.

The purpose of this study was to evaluate threshold and suprathreshold auditory risk from a newly popular platform of music concert entertainment; virtual reality (VR) headsets. Recreational noise exposure to music is the primary source of hearing hazard in young-adults, with noise doses of in-person concert venues and music festivals well in excess of the recommended daily exposure recommendation from the National Institute for Occupational Safety and Health. While research on the relationship between personal music players and noise-induced hearing loss risk is abundant, no study has yet evaluated noise-induced hearing loss risk from VR headsets, which are newest to the commercial market at this time. Thirty-one young-adult participants (18 to 25 years) with normal-hearing sensitivity (0 to 16 dB HL) experienced a VR music concert and participated in three data collection timepoints: Session A preexposure, Session A post-exposure, and Session B post-exposure. Participants underwent baseline testing for audiometry (0.25 to 20 kHz), distortion product otoacoustic emission testing (1 to 10 kHz), and Words-in-Noise testing. Participants then wore a commercially available VR headset (Meta Quest 2) and experienced a freely available online VR music concert (via the video-sharing website "YouTube"). The VR music concert duration was 90 min set to maximum volume, which yielded an average sound level equivalent of 78.7 dBA, max sound level of 88.2 dBA, and LC peak sound level of 98.6 dBA. Post-exposure testing was conducted immediately at the conclusion of the VR concert, and again within 24 hr to 1 week after the exposure. Participants also answered a questionnaire that estimated noise exposure history (National Acoustics Laboratory "Noise Calculator"). Post-exposure deficit was not observed in DPOAEs or Words-in-Noise score (p's > 0.05). However, statistically significant temporary post-exposure deficit was observed in audiometry at 4, 8, and 12.5 kHz (p's < 0.05) (mean differences: 2 to 3 dB HL). Twenty-four hours and 1-week post-exposure measurements revealed no permanent changes from baseline measurements (p's > 0.05) aside from one spurious difference at 12.5 kHz. Males tended to exhibit a significantly higher noise history score on average than females. The primary, secondary, and tertiary sources of noise hazard history in this young-adult cohort included amplified music. These preliminary data suggest that VR music concerts-which are likely to produce a substantially lower noise dose than in-person music concerts-may still be capable of producing at least slight, temporary threshold shifts on the order of 2 to 3 dB HL. Future research should include VR headsets in personal music player risk assessment, as the VR music concert platform is increasing rapidly in popularity among young-adults.

A Variable-Stimulus Distortion Product Otoacoustic Emission Screening Method to Match Cochlear Place-Specific Properties.

Distortion product otoacoustic emissions (DPOAEs) are a popular screening tool for hearing loss in specific populations (e.g., newborns). Current screening protocols use stimulus conditions that are agnostic to local mechanical properties of the cochlea and are also limited to a narrow frequency range. We have recently reported locally optimized stimulus frequency ratio and level combinations for recording DPOAEs up to stimulus frequencies of 19 kHz. In normally functioning cochlea, optimized stimuli improved the signal to noise ratios and allowed the registration of higher DPOAE levels, especially at higher frequencies. The purpose of this study was to evaluate the clinical performance of these physiologically motivated, locally appropriate, stimulus parameters for a screening application to identify the presence of hearing loss. Subjects were 24 adults with sensorineural hearing loss and 31 adults with normal hearing. The cubic DPOAE was measured and analyzed up to frequencies of 16 kHz using a range of stimulus conditions. Receiver operating characteristic curves were used to identify stimulus combinations most sensitive to screening for hearing loss. Receiver operating characteristic curves demonstrated improved test efficacy for hearing loss detection when using stimulus frequency ratios and levels that are frequency-dependent and consistent with known mechanical properties of the cochlea. We propose a new DPOAE recording paradigm (variable-stimuli DP) using stimuli aligned to local cochlear properties which may improve early and accurate detection of decline in cochlear function.

Tinnitus Generation and Behavioral Changes Caused by Chronic Stress: A Behavioral and Brain Study in a Rat Model.

This study explores the connection between chronic stress and tinnitus, a phantom auditory perception, using an animal model. Rats were subjected to 2 h of daily restraint stress for 10 days. Tinnitus was assessed on the last day of stress exposure using the gap response of pre-pulse inhibition acoustic reflex, measured at 60 dB background sound level at 8, 16, and 20 kHz. Chronic stress-exposed rats were categorized into two groups: tinnitus (RTG) and non-tinnitus (RNTG). Various tests, including hearing assessments (distortion product otoacoustic emissions and auditory brainstem response), behavioral evaluations (elevated plus maze test and forced swimming test), and immunohistochemical studies in the auditory and limbic brain regions, were conducted to understand the relationship between chronic stress, tinnitus, and behavioral changes. Following chronic restraint stress, 64.3% of the rats exhibited tinnitus with no audiometric changes. EPM and FST indicated an increase of anxiety- and depression-related behavior in RTG. Immunohistochemical analyses identified specific alterations in the expression of neurotransmitter receptors within brain regions implicated in tinnitus. Specifically, we observed a decrease in γ-aminobutyric acid A receptor α1 expression and an increase in glutamate receptor (N-methyl-D-aspartate receptor subunit 1 and receptor subunit 2B) expression in specific brain region. These changes suggest a reorganization of neural circuits associated with the tinnitus generation and behavioral changes of the rats after chronic stress exposure. Chronic stress alone can be a causal factor for the generation of tinnitus and behavioral changes through altered neural activities in tinnitus-related brain networks. NA Laryngoscope, 2024.

Associations Between Noise Exposure Level, Noise Kurtosis, and Distortion Product Otoacoustic Emissions in Young Workers With Normal Hearing.

Growing evidence has suggested that, in addition to noise exposure level, noise temporal structure (i.e., kurtosis) plays an important role in the development of noise-induced hearing loss, while most of the relevant research has been on the results of pure-tone audiometry. This study focuses on the combined effect of noise exposure level and noise kurtosis on distortion product otoacoustic emissions (DPOAEs) in young workers with normal hearing. A cross-sectional study among young workers in manufacturing industries was conducted in Zhejiang Province, China. Individual noise exposure measurements were performed on participants to obtain an A-weighted noise exposure level normalized to 8 hr (LAeq, 8hr), cumulative noise exposure (CNE), kurtosis, and kurtosis-adjusted CNE (CNE-K). The DPOAE test was performed on the participants and DPOAE levels were obtained. The relationships between noise exposure level, kurtosis, and DPOAE levels were explored by univariate analyses. Furthermore, multivariate regression models were conducted to estimate the combined effects of exposure level and kurtosis after adjusting for age, gender, and use of hearing protection devices. The overall DPOAE curves across frequency bands presented a fluctuating downward trend with increasing frequency. Both exposure level and kurtosis were found to be associated with decreases in DPOAE levels. The multivariate regression model including CNE-K as a joint indicator of complex noise showed an increased R2 compared with the model including CNE. After adjustment for age, gender, and the use of hearing protection devices, significant effects of CNE-K on DPOAE levels were observed at 3, 4, and 5 kHz frequencies, with maximum effect presented at 4 kHz. DPOAE is a sensitive test that can detect cochlear damage in limited areas that cannot be detected by conventional audiometry. The present study provided a more comprehensive understanding of the impact of complex noise on the DPOAE levels. It also suggested that CNE-K was an effective metric in assessing DPOAE levels associated with complex noise.

Effect of Age on Distortion Product Otoacoustic Emissions at Extended High Frequencies.

The inner ear is most susceptible to the aging effects. Distortion product otoacoustic emissions (DPOAEs) are a good indicator for interpreting the age effects but are usually recorded at up to 8000 Hz frequencies in routine audiologic testing. The present study was designed to assess and compare the DPOAEs at conventional frequencies and at extended high frequencies (EHFs) across different age groups. Extended high-frequency audiometry (9000-16000 Hz) and DPOAEs from 500-16000 Hz were recorded on 80 adult (160 ears) participants (15-55 years) with normal hearing sensitivity. The participants were categorized into 4 groups: group I (15-<25 years), group II (25-<35 years), group III (35-<45 years), and group IV (45-55 years). A statistically significant reduction in EHF thresholds was observed from group III onward. However, the thresholds were comparatively better for group III at frequencies 9000, 10000, and 11500Hz than group IV. No significant difference was observed for EHF DPOAEs in groups I and II (except at 16000 Hz) and III and IV. Distortion product otoacoustic emissions at conventional frequencies in group IV were significantly poorer than the other 3 groups. A weak negative correlation was observed between the DPOAE parameters and EHF thresholds. The effect of age was more pronounced on EHF DPOAEs than EHF thresholds for frequencies 9000, 10000, and 11500 Hz. Distortion product otoacoustic emissions at EHF started deteriorating below the age of 30 years and showed a rapid decline above 35 years. Extended high-frequency DPOAEs can be used as screening tools to assess the function of the basal part of the cochlea.

Sensorineural hearing loss in Lyme neuroborreliosis

Background Sensorineural hearing loss (SNHL) has been suggested to occur in patients with Lyme neuroborreliosis (LNB); however, a clear association has never been documented. The present study prospectively investigated the development of SNHL in patients admitted for treatment of LNB using distortion-product-oto-acoustic emissions (DPOAE) as a measure of cochlear function. Methods DOAE were measured in patients with LNB on the day of diagnosis, during treatment, and 30–60 days after discharge. Frequencies were categorized as Low (1, 1.5, 2 kHz), Mid (3, 4, 5 kHz), Mid-high (6, 7, 8 kHz), and High (9, 10 kHz). Pure Tone Audiometry (PTA3) was performed at discharge and 60 days after. Patients were treated with i.v. ceftriaxone or oral doxycycline for 14 days according to guidelines. Results DPOAE measurements were obtained in 25 patients with LNB at admission and in 18 patients at follow-up. Median age was 56 years (IQR, 48–64 years), and 16 (67%) were men. Fourteen (78%) of 18 patients showed improvement in Emission Threshold Levels (ETL) from admission to follow-up in low, mid-, and mid-high frequency categories, where ETLs increased by median levels of 3.2 (−4.1 to 8.3), 7.5 (−2.8 to 9.8), and 4.7 dB (−4.3 to 10.1). A decline was observed in the high frequency category, median −3.3 dB (−9.1 to 6.7). SNHL defined by pure tone average (PTA3) >20 dB was present in 11 out of 23 (48%) at discharge and in 9 out of 16 patients (56%) 60 days after discharge, which differed significantly from matched controls (Mann-Whitney test, p = 0.036). Conclusion LNB can lead to cochlear outer-hair cell dysfunction, resulting in temporary and long-term SNHL.

Comparative analysis of hearing loss caused by steady-state noise and impulse noise.

Varied noise environments, such as impulse noise and steady-state noise, may induce distinct patterns of hearing impairment among personnel exposed to prolonged noise. However, comparative studies on these effects remain limited. This study aims to delineate the different characteristics of hearing loss in workers exposed to steady-state noise and impulse noise. As of December 2020, 96 workers exposed to steady-state noise and 177 workers exposed to impulse noise were assessed. Hearing loss across various frequencies was measured using pure tone audiometry and distortion product otoacoustic emission (DPOAE) audiometry. Both groups of workers exposed to steady-state noise and impulse noise exhibited high frequencies hearing loss. The steady-state noise group displayed significantly greater hearing loss at lower frequencies in the early stages, spanning 1- 5 years of work (P < 0.05). Among individuals exposed to impulse noise for extended periods (over 10 years), the observed hearing loss surpassed that of the steady-state noise group, displaying a statistically significant difference (P < 0.05). Hearing loss resulting from both steady-state noise and impulse noise predominantly occurs at high frequencies. Early exposure to steady-state noise induces more pronounced hearing loss at speech frequencies compared to impulse noise.

Hearing Screening of Infant and Children Suspected of Congenital Hearing Loss at Dustira Cimahi Hospital

Hearing problems in children impact development, especially speech and language. Some risk factors are known to influence the occurrence of congenital deafness. For the last five years, screening with Otoacoustic Emissions (OAE) and Brainstem Evoked Response Audiometry (BERA) examinations has been used at Dustira Hospital to make a diagnosis and intervene as early as possible. This study aims to obtain the prevalence, risk factors, and OAE and BERA examination results at Dustira Cimahi Hospital. A retrospective descriptive study was conducted on children who underwent the OAE and BERA examination by collecting subject data for the period of January 2020– December 2022. The OAE examination uses distortion product otoacoustic emissions, while the BERA examination is based on the International Standard Organization (ISO). Of the 42 patients who were screened for hearing loss, the 3–5-year-old group was the most dominant (40.4%). Most of the patients were male (66%). While the prenatal risk factor was a history of TORCH infection (12%), the perinatal risk factor was low birth weight (14.2%) and the postnatal risk factor was hyperbilirubinemia (19%). The majority of the OAE examination results were refers found at 32 people (76.1%). The results of the BERA click examination were the presence of wave V found in 38 people (90.4%)). Patients with suspected congenital deafness who underwent hearing screening were in the age range of 3–5 years and were all male. The risk factors found were a history of TORCH infection, low birth weight, and hyperbilirubinemia. The majority of the results of the OAE examination was refer and that of the BERA was wave V. Keywords: BERA, children, congenital deafness, OAE

Detection of mild sensory hearing loss using a joint reflection-distortion otoacoustic emission profile.

Measuring and analyzing both nonlinear-distortion and linear-reflection otoacoustic emissions (OAEs) combined creates what we have termed a "joint-OAE profile." Here, we test whether these two classes of emissions have different sensitivities to hearing loss and whether our joint-OAE profile can detect mild-moderate hearing loss better than conventional OAE protocols have. 2f1-f2 distortion-product OAEs and stimulus-frequency OAEs were evoked with rapidly sweeping tones in 300 normal and impaired ears. Metrics included OAE amplitude for fixed-level stimuli as well as slope and compression features derived from OAE input/output functions. Results show that mild-moderate hearing loss impacts distortion and reflection emissions differently. Clinical decision theory was applied using OAE metrics to classify all ears as either normal-hearing or hearing-impaired. Our best OAE classifiers achieved 90% or better hit rates (with false positive rates of 5%-10%) for mild hearing loss, across a nearly five-octave range. In summary, results suggest that distortion and reflection emissions have distinct sensitivities to hearing loss, which supports the use of a joint-OAE approach for diagnosis. Results also indicate that analyzing both reflection and distortion OAEs together to detect mild hearing loss produces outstanding accuracy across the frequency range, exceeding that achieved by conventional OAE protocols.

Audiological Characteristics of a Sample of Adults With Misophonia.

The aim of this study was to describe the audiological test results from a sample of 60 adults with self-reported misophonia. Audiological testing was completed prior to participant randomization in a controlled trial for misophonia treatment. Participants completed the Inventory of Hyperacusis Symptoms Survey (IHS), the Tinnitus and Hearing Survey (THS), the Misophonia Questionnaire (MQ), and behavioral and objective audiometric measures. Hearing thresholds were less than 25 dBHL for 97% of the participants. Loudness discomfort levels for tonal stimuli suggested hyperacusis in 25% of the sample. Total scores on the IHS indicated that 12% met the clinical cutoff for hyperacusis, and, on the THS, 27% experienced problems with tinnitus, 77% experienced problems with hearing, and 53% experienced problems with sound tolerance. On the MQ, 37% indicated mild levels of misophonia and 58% indicated moderate levels. For speech-in-noise testing, a mild signal-to-noise ratio loss was present for 15% of participants. Most of the participants had present distortion product otoacoustic emissions (DPOAEs). Audiological data on individuals with misophonia are lacking. In this article, we present results from audiological testing on 60 adults with self-reported misophonia. Most had normal peripheral hearing sensitivity based on pure-tone audiometry and DPOAE measures; some had difficulties with sound sensitivities and understanding speech-in-noise, self-report indicated problems with hyperacusis, tinnitus, and hearing difficulty.

The Association between Aminoglycoside Exposure and Ototoxicity in Children with Cystic Fibrosis

Introduction: Pulmonary exacerbations increase the requirement of aminoglycoside (AG) antibiotics in people with cystic fibrosis (pwCF). Several studies have shown that AGs have a cumulative effect on ototoxicity. We aimed to investigate the relationship between AG exposure and ototoxicity by using 3 different methods in patients with CF. Materials/Methods: The multicenter study included 121 pwCF aged between 5 and 18 years with a history of parenteral AG exposure. Standard pure-tone audiometry, extended high-frequency pure-tone audiometry (EHF-PTA), and distortion-product otoacoustic emissions (DPOAE) tests were performed. Mitochondrial mutation analysis for m1555G>A was performed in 61 patients. Results: Median age was 12.85 years and 52.1% (n = 63) were male. 18.2% (n = 22) of the patients had received parenteral AGs more than 5 courses/lifetime. Ototoxicity was detected in at least one of the tests in 56.2% (n = 68) of the patients. Only 10.7% (n = 13) of the patients had reported a symptom indicating ototoxicity. 30.3% (n = 30) of the patients had ototoxicity in the low exposure group, while it was 45.5% (n = 10) in the high exposure group according to EHF-PTA (p > 0.05). Median number of parenteral amikacin courses was significantly higher in the ototoxic group (2 [1.25–5.75] vs. 2 [1–3]; p = 0.045). No m1555A>G mutation was detected in 61 patients who screened for mitochondrial mutation analysis. Conclusion: As AG ototoxicity occurs primarily at high frequencies, EHF-PTA is important in early detecting ototoxicity. EHF-PTA and DPOAE detected ototoxicity in some patients with normal PTA results. All pwCF with a history of AG exposure should be evaluated for hearing loss since symptoms may only be noticed in the late period.

Otoacoustic Estimate of Astronauts' Intracranial Pressure Changes During Spaceflight.

To investigate the potential correlation between prolonged exposure to microgravity on the International Space Station and increased intracranial fluid pressure, which is considered a risk factor for the astronauts' vision, and to explore the feasibility of using distortion product otoacoustic emissions as a non-invasive in-flight monitor for intracranial pressure changes. Distortion product otoacoustic emission phase measurements were taken from both ears of five astronauts pre-flight, in-flight, and post-flight. These measurements served as indirect indicators of intracranial pressure changes, given their high sensitivity to middle ear transmission alterations. The baseline pre-flight ground measurements were taken in the seated upright position. In-flight measurements revealed a significant systematic increase in otoacoustic phase, indicating elevated intracranial pressure during spaceflight compared to seated upright pre-flight ground baseline. Noteworthy, in two astronauts, strong agreement was also observed between the time course of the phase changes measured in the two ears during and after the mission. Reproducibility and stability of the probe placement in the ear canal were recognized as a critical issue. The study suggests that distortion product otoacoustic emissions hold promise as a non-invasive tool for monitoring intracranial pressure changes in astronauts during space missions. Pre-flight measurements in different body postures and probe fitting strategies based on the individual ear morphology are needed to validate and refine this approach.

Hearing Evaluations in Children With Retinoblastoma Treated With Intra-arterial Carboplatin Chemotherapy: A Single Institution Review.

To determine whether the administration of intra-arterial carboplatin affected the hearing of children with retinoblastoma. Children with retinoblastoma who were treated with intra-arterial carboplatin chemotherapy were included. Hearing tests before chemotherapy including tympanometry, distortion product otoacoustic emissions, and audiogram (if achievable) were performed and repeated 3 to 9 months after concluding intra-arterial therapy. The study was approved by the institutional review board. Patients were identified from the retinoblastoma clinic when the treatment plan included intra-arterial carboplatin chemotherapy. Children were excluded if they had previous intra-arterial carboplatin or preexisting hearing loss but were included if they had systemic carboplatin and dosing was available. Tympanometry was performed to rule out inner ear fluid. All examinations were performed by a certified audiologist with the same equipment, calibrated regularly by a certified technician. Twenty-two children (32 eyes) were evaluable. Because most children are diagnosed at a young age and are unable to participate in an audiogram, distortion product otoacoustic emission measurement was the primary measurement. No child displayed hearing loss. Intra-arterial chemotherapy with carboplatin did not cause ototoxicity in any child by distortion product otoacoustic emission measurement in contrast to systemic chemotherapy where ototoxicity is common. Distortion product otoacoustic emission levels were essentially unchanged from before to after intra-arterial chemotherapy in children with retinoblastoma. These findings suggest that intra-arterial carboplatin does not affect outer hair cell function, and distortion product otoacoustic emission tests can provide useful information when monitoring children at risk of developing carboplatin ototoxicity. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].

Hearing restoration by gene replacement therapy for a multisite-expressed gene in a mouse model of human DFNB111 deafness

Gene therapy has made significant progress in the treatment of hereditary hearing loss. However, most research has focused on deafness-related genes that are primarily expressed in hair cells with less attention given to multisite-expressed deafness genes. MPZL2, the second leading cause of mild-to-moderate hereditary deafness, is widely expressed in different inner ear cells. We generated a mouse model with a deletion in the Mpzl2 gene, which displayed moderate and slowly progressive hearing loss, mimicking the phenotype of individuals with DFNB111. We developed a gene replacement therapy system mediated by AAV-ie for efficient transduction in various types of cochlear cells. AAV-ie-Mpzl2 administration significantly lowered the auditory brainstem response and distortion product otoacoustic emission thresholds of Mpzl2-/- mice for at least seven months. AAV-ie-Mpzl2 delivery restored the structural integrity in both outer hair cells and Deiters cells. This study suggests the potential of gene therapy for MPZL2-related deafness and provides a proof of concept for gene therapy targeting other deafness-related genes that are expressed in different cell populations in the cochlea.