Search Results (258)

Background/Objectives: This study aimed to investigate the optimal sound presentation level for sound localization testing to assess the effect of hearing interventions in individuals with unilateral conductive hearing loss (UCHL). Methods: Nine participants with normal hearing were tested, and simulated two-stage UCHL was created using earmuffs and earplugs. We created two types of masking conditions: (1) only an earplug inserted, and (2) an earplug inserted with an earmuff worn. A sound localization test was performed for each condition. The sound presentation levels were 40, 45, 50, 55, 60, 65, and 70 dB SPL, and the results were evaluated using root mean square and d-values. Results: Both values showed little difference in masking Condition 2, regardless of the sound presentation level, whereas in masking Condition 1, the values were at their minimum at 55 dB SPL. In addition, comparing the differences between masking Conditions 1 and 2 for each sound presentation level, the greatest difference was observed at 55 dB SPL for both values. Conclusions: The optimal sound presentation level for sound localization testing to assess hearing intervention effects in UCHL was 55 dB. This result may be attributed to the effect of input from the non-masked ear, accounting for interaural attenuation; the effect was considered minimal at 55 dB SPL. Full article

Background/Objectives: Unilateral hearing loss (UHL), particularly single-sided deafness (SSD), disrupts spatial hearing in children, leading to academic and social challenges. This study aimed to (1) compare azimuthal sound-localization accuracy and compensatory strategies between children with single-sided deafness (SSD) and their normal-hearing (NH) peers within a virtual reality environment, and (2) investigate sound-localization performance across various azimuths by contrasting left-SSD (L-SSD) and right-SSD (R-SSD) groups. Methods: A cohort of 44 participants (20 NH, 24 SSD) performed sound localization tasks in a 3D virtual environment. Unsigned azimuth error (UAE), unsigned elevation error (UEE), and head movement distance were analyzed across six azimuthal angles (−75° to 75°) at 0°elevation. Non-parametric statistics (Mann–Whitney U tests, Holm–Bonferroni correction) compared performance between NH and SSD groups and within SSD subgroups (L-SSD vs. R-SSD). Results: The SSD group exhibited significantly higher UAE (mean: 22.4° vs. 3.69°, p < 0.0001), UEE (mean: 5.95° vs. 3.77°, p < 0.0001) and head movement distance (mean: 0.35° vs. 0.12°, p < 0.0001) compared with NH peers, indicating persistent localization deficits and compensatory effort. Within the SSD group, elevation performance was superior to azimuthal accuracy (mean UEE: 3.77° vs. mean UAE: 22.4°). Participants with R-SSD exhibited greater azimuthal errors at rightward angles (45°and 75°) and at −15°, as well as increased elevation errors at 75°. Hemifield-specific advantages were strongest at extreme lateral angles (75°). Conclusions: Children with SSD rely on insufficient compensatory head movements to resolve monaural spatial ambiguity in order to localize sounds. Localization deficits and the effort associated with localization task call for action in addressing these issues in dynamic environments such as the classroom. L-SSD subjects outperformed R-SSD peers, highlighting hemispheric specialization in spatial hearing and the need to study its neural basis to develop targeted rehabilitation and classroom support. The hemifield advantages described in this study call for further data collection and research on the topic. Full article

Background/Objectives: The vestibulo-respiratory reflex regulates the tension of the respiratory muscles, which prevents apneas and awakenings during sleep. This study aimed to determine whether functional deficits in the inner ear disturb sleep quality. Methods: We compared sleep parameters in patients with their first episode of acute inner ear deficit (Group A: sudden idiopathic vertigo attack, sudden sensorineural hearing loss), chronic functional inner ear impairment (Group B: chronic peripheral vertigo, permanent hearing loss), and in healthy individuals (Group C). Polygraphy recordings were performed twice, in Group A at the onset of acute otoneurological symptoms and the second time after their withdrawal with an interval of 1 to 13 days, in Group B after 1 to 6 days, and in Group C after 1 to 8 days. Results: In Group A during the symptomatic night, overall and central apnea-hypopnea indices were significantly higher and snoring time was longer. Group A also had higher central apnea-hypopnea index on the first night compared to healthy individuals. In chronic disorders, sleep recordings showed lower autonomic arousal index than in controls or symptomatic nights in Group A. Conclusions: These findings highlight the severity of sleep apnea indicators in Group A. Our results suggest that acute dysfunction of the inner ear substantially impacts central neuronal signaling responsible for regulating normal sleep-related breathing and leads to a deterioration in sleep quality in contrast to individuals with chronic inner ear impairments. It can also be assumed that people with chronic vertigo or hearing loss experience less interrupted sleep than healthy individuals. Full article

Background/Objectives: Sudden sensorineural hearing loss (SSNHL) is an acute condition with unclear etiology, commonly hypothesized to be associated with viral infections. Acute respiratory tract infections (RTIs), particularly those of viral origin, have been implicated in SSNHL through proposed mechanisms such as cochlear invasion and immune-mediated damage. However, robust large-scale epidemiological evidence examining this association remains limited. This study aimed to investigate the potential association between acute RTIs and subsequent risk of developing SSNHL across diverse populations. Methods: We conducted a multinational retrospective cohort study using data from the TriNetX Global Collaborative Network. Adults diagnosed with acute RTIs between 1 January 2012 and 30 June 2023 were compared to matched controls without RTI exposure. Patients with predisposing conditions for SSNHL were excluded. Propensity score matching (1:1) was performed by age and sex. SSNHL diagnoses within 60 days post index were analyzed using Cox proportional hazards models. Subgroup and sensitivity analyses were conducted by race, sex, and age strata. Results: Among 37 million patients analyzed, individuals with acute RTIs had a lower incidence of SSNHL compared to matched controls. Hazard ratios (HRs) for SSNHL were significantly reduced across all racial groups: Whites (HR: 0.572), Blacks (HR: 0.563), and Asians (HR: 0.409). Subgroup analyses revealed stronger inverse associations in males and younger age groups, particularly those aged 18–25 years. Conclusions: Contrary to prior assumptions, acute RTIs were associated with a lower incidence of SSNHL in a large, diverse cohort. While the findings raise the possibility of immunological or physiological factors influencing this association, the results should be interpreted with caution due to unmeasured confounding and the observational nature of the study. Full article

Background/Objectives: Hearing aids are essential for managing hearing loss, yet their accessibility, consistent use, and maintenance remain challenging in public healthcare systems, particularly in low- and middle-income countries (LMICs) such as South Africa. Despite the availability of these services, many patients struggle with device utilization, resulting in suboptimal rehabilitation outcomes. This study explores patient experiences with hearing aids in South Africa’s public healthcare sector. This study aimed to (1) assess patients’ experiences with hearing aid access, including waiting times and service delivery; (2) identify challenges related to hearing aid maintenance and repairs in the public sector; (3) explore factors influencing consistent hearing aid use, including social, psychological, and practical barriers; and (4) propose strategies to enhance hearing aid provision and aftercare services in South Africa. Methods: This descriptive qualitative study was conducted at two public healthcare facilities in Johannesburg. Purposive sampling was used to recruit 15 adult hearing aid users who had received government-funded hearing aids within the past 12 months. Semi-structured interviews were conducted, transcribed verbatim, and analyzed using thematic analysis. Results: Participants reported long waiting periods (up to a year) for hearing aids, with poor communication regarding timelines. Challenges included difficulties adjusting to amplification, discomfort, and battery shortages, leading to inconsistent use or device abandonment. Social stigma and lack of family support further discouraged consistent use. Repair services were slow, with waiting times exceeding three months. Participants recommended decentralized battery distribution, structured follow-up appointments, improved aftercare, awareness campaigns, and mobile audiology services to improve accessibility and usability. Conclusions: While public hearing aid provision is essential for hearing rehabilitation, systemic inefficiencies, maintenance issues, and social barriers limit its impact. Strengthening aftercare services, decentralizing hearing aid distribution, and increasing public awareness could significantly improve hearing aid accessibility and adherence. Furthermore, policy interventions that incorporate tele-audiology, community-based maintenance programs, and integrated healthcare approaches are crucial in ensuring sustainable hearing healthcare outcomes. Full article

A single intratympanic application of the small-molecule drug AC102 was previously shown to promote significant recovery of hearing thresholds in a noise-induced hearing loss model in guinea pigs. Here, we report the effects of AC102 to revert synaptopathy of inner hair cells (IHCs) and behavioral signs of tinnitus in Mongolian gerbils following mild noise trauma. This experimental protocol led to minor hearing threshold shifts with no loss of auditory hair cells (HCs) but induced synaptopathy and a sustained and significant tinnitus percept. Treatment by intratympanic application of AC102 was evaluated in two protocols: 1. three weekly injections or 2. a single application. We evaluated hearing threshold changes using the auditory brainstem response (ABR) and the development of a tinnitus percept using the gap prepulse inhibition of acoustic startle (GPIAS) behavioral response. The number of IHC ribbon synapses along the cochlear frequency map were counted by immunostaining for the synaptic ribbon protein carboxy-terminal binding protein 2 (CTBP2). AC102 strongly and significantly reduced behavioral signs of tinnitus, as reflected by altered GPIAS. Noise-induced loss of IHC ribbon synapses was significantly reduced by AC102 compared to vehicle-treated ears. These results demonstrate that a single application of AC102 restores ribbon synapses following mild noise trauma thereby promoting recovery from tinnitus-related behavioral responses in vivo. Full article

Background/Objectives: CMV (cytomegalovirus) is associated with several developmental disorders. The incidence of congenital cytomegalovirus infection is around 1%, depending on the region. Previous prospective studies have shown that certain ultrasound findings are predictive factors for prenatal CMV infection. Methods: During this systematic review, we searched PubMed and Embas. Out of 569 results, 19 met our search criteria (we included cases where prenatally positive amniocentesis PCR for CMV was performed or autopsy confirmed the CMV diagnosis). A total of 237 cases were reported from 19 studies. Results: In 64 cases, abortion or perinatal death occurred. The most common prenatal abnormalities were small for gestational age (n = 47), ventriculomegaly (n = 51), and hyperechogenic bowels (n = 39). A subependymal cyst was the most common prenatal MRI abnormality (n = 20). Hearing loss was observed in 61 cases (42 mild, 19 severe). Among prenatal signs, we found a correlation between hearing loss and ventriculomegaly (Fisher’s exact test, p = 0.0052). The most common neurological complication was speech delay. We were able to demonstrate a prenatal association with neurological complications and subependymal cyst (Fisher’s exact test, p = 0.00003547), but this pattern could only be reliably seen with MRI. Conclusions: In prenatally diagnosed CMV infection, ultrasound signals may be suitable for estimating the outcome. Conducting a prospective study and establishing a score would be worthwhile for its clinical application. In cases of ultrasound abnormalities and suspicion of CMV, it is worth performing a prenatal MRI, even in everyday practice. Full article

Background/Objectives: The conventional strategy for addressing age-related hearing loss is hearing aid (HA) use, yet many individuals underutilize their devices. Despite the positive effects of HA use, adherence remains low, highlighting the importance of studying associated variables. We hypothesize that better unaided speech perception in noise (SPiN) would be associated with greater perceived benefit from HAs, which, in turn, would be linked to increased HA use. Methods: A cross-sectional study design was used, including 114 older adults (≥65 years) who were HA users. HA use and perceived benefit were assessed using questions 1 and 2 of the International Outcome Inventory for Hearing Aids (IOI-HAs), while unaided SPiN performance was measured monaurally with a speech-in-noise test. In the mediation analysis, SPiN performance was the predictor, perceived benefit the mediator, and HA use the outcome. Direct and indirect effects were evaluated using generalized structural equation modeling. Results: No significant total effect was found for the right ear. For the left ear, there was a significant indirect effect of SPiN performance on HA use through perceived benefit (OR = 1.26, 95% CI 1.06–1.57, p = 0.019) but no direct effect (p = 0.563). In addition, a significant total effect of left ear SPiN performance on HA use was observed (p = 0.041). Conclusions: The findings suggest that unaided SPiN performance—particularly in the left ear—may be indirectly associated with HA use through its effect on perceived benefit. These results underscore the potential value of including SPiN assessments in the HA fitting process and counseling strategies for older adults. Full article

Radiotherapy-induced hearing impairment significantly affects patients’ quality of life, yet its genetic basis remains poorly understood. This study seeks to identify genetic variants associated with radiotherapy-induced tinnitus and hearing loss and explore their functional implications. A genome-wide association study (GWAS) was conducted to identify single-nucleotide polymorphisms (SNPs) associated with radiotherapy-induced tinnitus and hearing loss. Protein–protein interaction networks and functional enrichment analyses were performed to explore underlying biological pathways. A phenome-wide association study (PheWAS) analysis across five databases examined associations between identified SNPs and various phenotypes. The GWAS identified 97 SNPs significantly associated with radiotherapy-induced tinnitus and 76 SNPs with hearing loss. Tinnitus-associated variants were enriched in pathways involving Wnt signaling and telomerase RNA regulation, while hearing-loss-associated variants were linked to calcium-dependent cell adhesion and neurotransmitter receptor regulation. The PheWAS analysis revealed significant associations between these hearing-impairment-related SNPs and metabolic phenotypes, particularly BMI and metabolic disorders. A chromosomal distribution analysis showed concentrated significant SNPs on chromosomes 1, 2, 5, and 10. This study identified distinct genetic architectures underlying radiotherapy-induced tinnitus and hearing loss, revealing different molecular pathways involved in their pathogenesis. The unexpected association with metabolic phenotypes suggests potential interactions between metabolic status and susceptibility to radiotherapy-induced hearing complications. These findings provide insights for developing genetic screening tools and targeted interventions to prevent or mitigate radiotherapy-related hearing damage. Full article

Objectives: Our aim was to determine the prevalence of middle ear disorders and associated risk factors that contribute to speech and language developmental delays in children with Down Syndrome. Methods: A prospective, cross-sectional study was conducted in 70 children with Down Syndrome between the ages of 1 and 18. Data, including complete physical and otorhinolaryngological examinations, hearing tests, and evaluation of speech and language skills, was compared to a historic typical control group. Results: Recurrent otitis media was significantly higher in the study group (56.5%) compared to the control (26%) (p = 0.05). The rate of conductive hearing loss was significantly higher in the study group (71.2%) compared to the control (14.9%) (p = 0.0001). Conductive hearing loss was statistically associated with delayed speech development (p = 0.046). Conclusions: Middle ear disorders are common in children with Down Syndrome and are associated with conductive hearing loss and delay of speech and language development. This study emphasizes the importance of routine examination of this population by an Otorhinolaryngologist and speech therapist. Full article

Objectives: This study assessed the potential benefits of supplemental flunarizine administration in patients with sudden sensorineural hearing loss (SSNHL) experiencing incomplete recovery with conventional steroid treatment. Methods: Thirty-nine SSNHL patients, unresponsive to conventional steroid therapy, received either oral ginkgo biloba (control group, n = 24) or a combination of oral ginkgo biloba and flunarizine (treatment group, n = 15). Pure-tone average (PTA) evaluation at 0.5, 1, 2, and 4 kHz was conducted upon each patient’s visits. A change of ≥10 dB was considered ‘significant hearing gain’. Results: The treatment group showed a higher rate of hearing gain ≥10 dB (46.7%) compared to the control group (12.5%) (p = 0.03). Additional treatment with flunarizine was associated with greater improvement in hearing thresholds compared with ginkgo biloba alone (p = 0.004), suggesting a potential therapeutic benefit. Conclusion: This retrospective study suggests that flunarizine may provide additional benefit in patients with SSNHL experiencing incomplete recovery following conventional steroid treatment. These findings are preliminary and require validation in larger, controlled studies. Full article

Age-related hearing loss (ARHL) is a highly prevalent, burdensome sensorineural hearing loss closely associated with impaired autophagic influx. Our previous studies revealed that neuritin, a neurotrophic factor primarily expressed in the central nervous system, could alleviate drug-induced damages in hair cells (HCs) and spiral ganglion neurons. However, its effects on ARHL and whether these effects are closely related to autophagy remain unclear. Using the Nrn1 knock-in mice and cultured cochlear basilar membrane (CBM) of the neonatal mouse, we show that neuritin could restore aging-associated hearing loss and alleviate senescence-associated damage in the cochlea. Overexpression of neuritin in support cells (SCs) alleviates the loss of cochlear HCs and nerve fibers, reducing the damage to spiral ganglion neurons and the shifts in ABR’s high-frequency threshold. Furthermore, conditional overexpression of neuritin in SCs improves autophagic influx by upregulating the expression of microtubule-associated protein 1 light chain 3 type B (LCB3) protein and downregulating the expression of p21 protein. In cultured neonatal mouse CBM, neuritin administration significantly inhibits D-galactose-induced HC loss, cellular apoptosis, and ROS production and promotes autophagic influx. These effects were weakened when the autophagy inhibitor 3-MA was added. In summary, our results confirm the therapeutic potential of neuritin treatment for ARHL. Full article

Cytomegalovirus (CMV) infection in pregnant women is one of the most common causes of congenital infection in children. It is often asymptomatic but can lead to serious complications, including progressive sensorineural hearing loss. Profound hearing loss is an indication for cochlear implantation (CI). Electrode impedance and neural response telemetry (NRT) thresholds can be measured to confirm correct electrode placement and speech processor programming. Background/Objectives: The aim of the study is to evaluate the hearing outcome of children with profound sensorineural hearing loss or deafness due to cCMV infection after CI compared to a control group of children born with other causes of congenital hearing loss and to identify prognostic factors predicting the outcome of patients with hearing loss due to cCMV infection after CI. Methods: A retrospective study was conducted in patients implanted between 2016 and 2023 at the Department of Otolaryngology of the Institute of the Polish Mother’s Memorial Hospital Research Institute in Łódź. Pre- and postoperative hearing levels, electrode impedance and neural response telemetry (NRT) thresholds were compared. The degree of pre-implantation hearing loss was assessed by the level of the recorded V-wave in the ABR test. Post-implantation hearing assessment was based on the last available free-field tonal audiometry measurement. Impedance measurements were included: intraoperative, 1, 6, 12 months after CI, respectively, and NRT thresholds. Results: The final analysis included 84 patients with profound sensorineural hearing loss and complete audiological follow-up data: 13 patients with congenital CMV (cCMV) infection and 71 patients with other causes of deafnes. The analysis included 175 implanted ears: 17 in the CMV group and 158 in the control group. The age at implantation ranged from 1 to 11 years in the CMV and from 1 to 13 years in the control group. Mean preoperative hearing thresholds were 94.54 dB in the CMV group and 97.04 dB in the control group. At the most recent postoperative evaluation, mean thresholds improved to 33.83 dB and 36.42 dB, respectively. No statistically significant differences were observed between the groups. Mean intraoperative NRT values were 79.74 in the CMV group and 86.90 in the non-CMV group. Final NRT values were 129.77 and 130.76, respectively. Mean impedance values measured intraoperatively and at 1, 6 and 12 months postoperatively were 11.09 kOhm, 13.40 kOhm, 8.35 kOhm and 8.25 kOhm in the CMV group; and 12.28 kOhm, 14.06 kOhm, 9.60 kOhm and 8.00 kOhm in the control group, respectively. Conclusions: CI in children with deafness caused by cCMV infection is an effective treatment option. Initial electrical impedance values of the electrodes increase after implant activation and decrease in subsequent months of follow-up, suggesting the absence of active adhesion processes in the cochlea. Full article

P2X receptors are unspecific cation channels activated by ATP. They are expressed in various tissues and found in neuronal and immune cells. In mammals, seven subunits are described, which can assemble into homomeric and heteromeric trimers. P2X2 receptors play important roles in cochlear adaptation to elevated sound levels. Three mutations causing inherited progressive hearing loss have been identified. These mutations localize to the transmembrane domain 1 (V60L), the transmembrane domain 2 (G353R) and a β-sheet linking the ATP binding site to the pore (D273Y). Herein, mutations were studied in human homomeric P2X2 as well as in heteromeric P2X2/3 receptors. We measured their binding of a fluorescently labeled ATP derivative (fATP) and characterized the constructs using the patch-clamp technique. The conclusions from our results are as follows: 1. The mutations V60L and G353R show robust localization on the plasma membrane and binding of fATP, whereas the mutant D273Y has no binding to fATP. 2. The mutation V60L has an increased affinity to fATP compared with the wildtype. 3. The expression of hP2X2 V60L channels reduces cell viability, which may support its role in the pathogenesis of hearing loss. 4. All mutant P2X2 subunits can assemble into P2X2/3 heteromeric channels with distinct phenotypes. Full article

Hearing loss remains a significant but underexplored health challenge in individuals with HIV/AIDS, particularly those exposed to occupational noise. The ototoxic effects of antiretroviral therapy (ART) and comorbid conditions like tuberculosis (TB) further compound the risk. This narrative review examines the intersection of HIV/AIDS, ART, and occupational noise-induced hearing loss (ONIHL), emphasizing the South African and broader African contexts. The aim of the study was to map the existing literature on the association between HIV/AIDS, its treatments, and ONIHL, and to identify research gaps to inform policy and clinical practice. A narrative review approach was adopted, systematically searching databases including PubMed, Scopus, and Web of Science. Studies published between 2000 and 2024 were included, focusing on the effects of HIV/AIDS, ART, and occupational noise exposure on hearing health. Data extraction and thematic synthesis were performed to identify key findings and gaps. Twenty studies were included, covering diverse settings such as South Africa, Cameroon, Tanzania, and the USA. Three key themes emerged: (1) dual burden of HIV and occupational noise exposure: HIV-positive individuals in noise-intensive industries, such as mining, face amplified risks of hearing loss due to immunological compromise and ototoxic TB treatments; (2) ototoxicity of ART: older ART regimens, widely used in resource-limited settings, are associated with a higher prevalence of sensorineural hearing loss (SNHL); and (3) immunological susceptibility to ONIHL: HIV-related immune suppression exacerbates cochlear damage from noise and ototoxic agents, contributing to both peripheral and central auditory dysfunction. This review highlights the urgent need for integrated hearing health interventions in HIV care and occupational health frameworks, particularly in high-prevalence regions like South Africa. Routine audiological assessments, access to safer ART regimens, and enhanced workplace protections are essential to mitigate the dual burden of HIV/AIDS and ONIHL. Future research should prioritize longitudinal studies and innovative, low-cost solutions for resource-limited settings. Full article