The human auditory system is able to improve speech intelligibility in challenging multi-talker scenarios by using the binaural cues [Interaural Time Differences (ITDs) and Interaural Level Differences (ILDs)] for spatially separated talkers. However, aging and hearing loss can vastly degrade a listener's ability to perceive ITDs, resulting in a decreased binaural benefit. For this reason, we investigated a method to transform imperceptible ITDs (artificially removed to simulate ITD sensitivity loss) into low-frequency ILDs to assess the binaural benefit that can be gained this way, based on listening experiments with normal-hearing listeners. In a reverberant environment, no binaural benefit was found. In an anechoic environment and with a central target speaker, the decrease in speech reception tresholds because of removed ITDs was almost completely compensated when low-frequency ILDs were added. For a lateral target speaker, the low-frequency ILDs even provided a significant improvement over the baseline where ITDs and ILDs are available. Simulations using the binaural speech intelligibility model (BSIM) supported the measured results from the listening experiment. These findings suggest that this cue conversion method could potentially bring a benefit to hearing impaired and elderly listeners when implemented in cochlear implants and hearing aids.

Background Conductive hearing loss (CHL) is a significant contributor to hearing impairment, especially in low-income settings. Chronic suppurative otitis media (CSOM) is often a dominant cause in developing regions. This study examined the causes and clinical profiles of patients with CHL at Khartoum Ear, Nose and Throat (ENT) Hospital. Methods We conducted a retrospective descriptive cross-sectional study of 106 patients diagnosed with CHL (confirmed by audiometry or tuning-fork testing) who presented between October 2021 and March 2022. Demographic data, etiologies, and associated symptoms were extracted from medical records and analysed descriptively. Results The cohort (mean age 27 years) comprised 61 (57.5%) female patients, predominantly young adults with 54 (51%) patients aged 18-35 years. CSOM was the leading cause of CHL, affecting 50 (47.2%) patients, far exceeding other etiologies. Smaller proportions were due to ear canal foreign bodies in seven (6.6%) participants, external auditory polyps in seven (6.6%), otosclerosis in five (4.7%), and various others (each <4%). The majority of cases were acquired, seen in 99 cases (93.4%) and only four (3.8%) were congenital cases. Most patients had mild-to-moderate hearing loss, with 50 (47.2%) patients reporting progressive loss. Common accompanying symptoms included ear discharge in 70 people (66.0%), tinnitus in 62 (58.9%), ear pain in 61 (57.5%), vertigo in 36 (34.0%), and ear itch in 28 (26.4%) participants. Conclusion CSOM predominated as the etiology of CHL in this Sudanese ENT hospital, reflecting a high burden of preventable ear infection. The findings underscore the need for early detection and management of CSOM and related conditions to reduce CHL. The data from this study highlights the need for public health intervention in tackling preventable infectious diseases in Khartoum.

Craniofacial microsomia (CFM) exhibits significant phenotypic variability and degree of severity. While loss-of-function variants in SF3B2 have recently emerged as a genetic etiology, the molecular basis underlying this clinical heterogeneity remains poorly understood. Here, we report two probands harboring novel truncating SF3B2 variants and presenting with distinct clinical phenotypes. Proband 1, with a heterozygous p.(Gln60*) variant, exhibited characteristic CFM features, including mandibular hypoplasia, cleft palate, bilateral tragal abnormalities, microtia, external auditory canal stenosis with hearing impairment, and an epibulbar dermoid. In contrast, Proband 2, carrying a p.(Lys507*) variant, exhibited a milder craniofacial phenotype, although he had hearing loss and developmental delay that could not be explained with certainty by the SF3B2-variant. Western blot analysis demonstrated complete loss of p.(Gln60*) protein, whereas the p.(Lys507*) variant-despite lying outside the predicted nonsense-mediated decay (NMD) escape region-retained 15.5% residual expression of truncated protein. To investigate functional consequences, we performed CRISPR/Cas9-mediated sf3b2 knockout in zebrafish. Mutant larvae showed a 25.33% malformation rate and recapitulated human craniofacial features, including a reduced head-to-body length ratio (p = 0.0013), hypoplastic mandibular cartilage-evidenced by shortened Meckel's cartilage (p = 0.0104) and Palatoquadrate (p = 0.0174)-and impaired skeletal mineralization (p = 0.0028). Together, these findings suggest that truncating variants at different positions may be associated with differential protein expression levels and variable clinical presentations. Our study reinforces SF3B2's role as a loss-of-function disease gene and highlights the importance of variant-specific molecular characterization in understanding CFM.

BackgroundEnvironmental noise is an under-recognised public health hazard in rapidly urbanising low- and middle-income countries. Urban slum residents are disproportionately exposed to chronic transportation and occupational noise, yet community-level evidence linking noise exposure with ear morbidity remains limited in India.ObjectivesTo assess the association between environmental noise exposure and ear morbidity in urban slums of Bhubaneswar, Odisha. To examine behavioural and socio-environmental determinants of ear health among the sample for associations to offer recommendations.MethodsThe study design is a community-based, stratified, cross-sectional study conducted in the urban slums of Bhubaneswar, Odisha, India, stratified into low-, medium-, and high-noise zones. The study population were 384 residents aged 10-50 years selected through stratified random sampling with proportional allocation. The noise stratification is generalised, on the basis of city administrative definitions.Data were collected using a semi-structured questionnaire that assessed socio-demographics, occupational exposure, ear hygiene, and health-seeking behaviour. Clinical ear examination, otoscopy and tuning fork tests were conducted. Logistic limitations did not permit performing pure tone audiometry. Ear health outcomes included normal, ear infection, at risk hearing loss or both. Associations were analysed using the chi-square test and multivariable logistic regression, with statistical significance at p<0.05.ResultsAmong 384 participants, the overall prevalence of ear morbidity was 21.1% (95% CI: 17.2-25.4), including ear infections at 11.2% (95% CI: 8.3-14.8), at-risk hearing loss at 2.6% (95% CI: 1.3-4.8), and combined infection with hearing loss at 7.3% (95% CI: 5.0-10.3). A graded increase in hearing loss risk was observed across noise exposure zones-2.4% in low, 10.9% in medium, and 15.6% in high noise areas (χ[2]=13.21, p=0.001). External ear canal abnormalities were also significantly linked to higher regional noise exposure (χ[2]=19.78, p<0.001). Behavioural factors, including unsafe ear-cleaning practices (χ[2]=24.57, p=0.017), a history of ear infection (χ[2]=39.59, p<0.001), and ear piercing (χ[2]=15.38, p=0.002), showed significant associations with morbidity. Multivariable analysis revealed greater odds of ear morbidity among residents of high-noise zones (AOR≈8.5; 95% CI: 2.9-25.1), emphasising the combined environmental and behavioural risk factors.ConclusionEnvironmental noise exposure is a significant yet under-recognised determinant of ear morbidity among urban slum residents, exacerbated by unsafe hygiene behaviours and limited preventive care. Integrating ear and hearing services within primary health care and strengthening urban environmental regulation are essential. The study supports progress toward SDG 3 (Good Health and Well-Being), SDG 11 (Sustainable Cities and Communities), and SDG 6 (Clean Water and Sanitation) through multisectoral strategies that address environmental and social determinants of ear health. The community-based stratification provides a pragmatic assessment of environmental noise exposure; however, the cross-sectional design and the absence of individual noise exposure measurements and gold-standard hearing assessments (pure-tone audiometry) limit causal inference.