Hearing Ability Research Articles

Relationship between attention and spatial processing abilities

Reduction in an individual’s hearing ability and their working memory (WM) capacity are hypothesized to be two of the major contributors to the decline in listener performance seen in complex listening environments. Generally, the improvement in speech intelligibility that may occur when a target is spatially separated from competing talkers is quantified as spatial release from masking (SRM). The goal of this study was to estimate working memory capacity based on a divided attention version of the classic spatial release from masking task (the temporal overlap task) and the classic abbreviated reading span task (aRST). Temporal overlap threshold was estimated by adaptively varying the maximum amount of temporal overlap of the signals where a listener could still correctly identify the speech source presented directly ahead of the listener when the speech material was either colocated or spatially separated. Initial analyses of the data revealed a strong relationship between SRM and temporal overlap thresholds, suggesting that SRM is driven by the listeners’ ability to modulate their attentional mechanisms. The relationship between SRM, temporal overlap thresholds, and reading span measures will also be discussed.

Auditory brainstem implantation: surgical experience and audiometric outcomes in the pediatric population.

Pediatric data regarding treatment via an auditory brainstem implant (ABI) remains sparse. The authors aimed to describe their experience at their institution and to delineate associated demographic data, audiometric outcomes, and surgical parameters. An IRB-approved, retrospective chart review was conducted among the authors' pediatric patients who had undergone auditory brainstem implantation between 2012 and 2021. Demographic information including sex, age, race, coexisting syndrome(s), history of cochlear implant placement, average duration of implant use, and follow-up outcomes were collected. Surgical parameters collected included approach, intraoperative findings, number of electrodes activated, and complications. A total of 19 pediatric patients had an ABI placed at the authors' institution, with a mean age at surgery of 4.7 years (range 1.5-17.8 years). A total of 17 patients (89.5%) had bilateral cochlear nerve aplasia/dysplasia, 1 (5.3%) had unilateral cochlear nerve aplasia/dysplasia, and 1 (5.3%) had a hypoplastic cochlea with ossification. A total of 11 patients (57.9%) had a history of cochlear implants that were ineffective and required removal. The mean length of implant use was 5.31 years (0.25-10 years). Two patients (10.5%) experienced CSF-related complications requiring further surgical intervention. The most recent audiometric outcomes demonstrated that 15 patients (78.9%) showed improvement in their hearing ability: 5 with sound/speech awareness, 5 able to discriminate among speech and environmental sounds, and 5 able to understand common phrases/conversation without lip reading. Nine patients (47.4%) are in a school for the deaf and 7 (36.8%) are in a mainstream school with support. The authors' surgical experience with a multidisciplinary team demonstrates that the retrosigmoid approach for ABI placement in children with inner ear pathologies and severe sensorineural hearing loss is a safe and effective treatment modality. Audiometric outcome data showed that nearly 79% of these patients had an improvement in their environmental and speech awareness. Further multicenter collaborations are necessary to improve these outcomes and potentially standardize/enhance electrode placement.

Application of speech induced ABR in rehabilitation intervention for hearing impaired children

Objective:Exploring the electrophysiological changes of auditory rehabilitation in young children with hearing impairment, providing more methods for early assessment and intervention. Methods:Twenty children aged 2-4 were enrolled, with moderate hearing loss and no other abnormalities in the ears. Divide them into group 1 with normal hearing, group 2 with abnormal hearing, group 3 with abnormal hearing receiving hearing aid intervention for one year, and group 4 with abnormal hearing receiving hearing aid and language training rehabilitation for one year. The SmartEP auditory evoked potential instrument was used to detect speech induced ABR and conduct screening for 'Standards and Evaluating Hearing and Language Abilities of Children with Hearing Impairment in 80 enrolled children after rehabilitation training, and the latency、amplitude of speech induced ABR waveform and evaluation scale scores for each group after rehabilitation intervention were compared. Results:Compared with the normal group, the latency of each wave in the other three groups was prolonged. The differences in each wave between Group 2 and Group 3 were statistically significant, while the differences in D and F waves between Group 3 and Group 4 were statistically significant. Compared with the normal group, the maximum amplitude at F0 decreased in the other three groups, and the differences in maximum amplitude between Group 2 and Group 3, Group 2 and Group 4, and Group 3 and Group 4 were statistically significant. Compared with the normal group, the scores of the auditory language assessment scale in the hearing intervention group and the hearing aid plus language training group were significantly higher than those in the abnormal group in terms of recognition rate. The recognition rates of hearing impaired children with language training foundation are similar to those of the normal group of children. Conclusion:Auditory rehabilitation can alter the electrophysiological aspects of hearing and serve as a basis for early assessment and intervention in young children.

The contributions of acoustic and non-acoustic factors to spatial release from masking

The ability to identify speech at worse signal-to-noise ratios when the maskers are spatially separated compared to when they are colocated is called spatial release from masking (SRM) and is thought to be a combination of monaural and binaural advantages arising from spatially separating the target from the maskers. Also, a host of other cognitive skills including attention, working memory, and executive function that support listeners’ ability to segregate, track and attend to a “target” signal while tuning out other unwanted signals contributes to understanding speech better in complex environments. Previous research with young normal hearing listeners from our lab indicated that SRM was predicted by an individual’s ability to use binaural cues (ITD thresholds), switch attention between two streams of information (trail making test) and ability to suppress irrelevant information (flanker task). Here, we present data from older listeners with varying hearing abilities on acoustic (envITD sensitivity) and non-acoustic tasks measuring attention (auditory and visual single and dual task), processing (trail making task), executive control (flanker task) and speech in noise tests (spatial release from masking using coordinate Response Measure sentences). The relationship between these acoustic and non-acoustic factors to speech understanding in complex listening environments will be discussed.

Listening effort mitigates rollover effects on speech-in-noise perception

Increasing the sound intensity may lead to worse speech understanding, especially in noise. This is known as the “Rollover” phenomenon. There is mounting evidence that listening effort plays an important role in challenging listening conditions and can be directly quantified with objective measures such as pupil dilation. However, there is limited understanding of how listening effort relates to rollover in speech understanding. We hypothesized that listening effort plays an essential role in mitigating rollover effects to differential extents across age and hearing status. We recruited across the adult lifespan (N = 50, 20–83 years) with different hearing statuses in acoustic listeners and cochlear implant users to perform a speech discrimination task. Minimal word pairs were presented both in quiet and in 0 dB SNR babble noise, ranging from 35–85 dB SPL. Pupil area was tracked simultaneously with behavioral responses during the task. We found that normal-hearing listeners are fully able to utilize effort contributions to minimize rollover effects between in quiet and in noise conditions, with diminishing benefit as a function of age and increased hearing loss. The results of this project could broadly influence how to design future hearing devices and interventions that maximize hearing abilities for those affected by hearing loss.

Military and Nonmilitary TBI Associations with Hearing Loss and Self-Reported Hearing Difficulty among Active-Duty Service Members and Veterans.

Identify associations between self-reported history of military and nonmilitary traumatic brain injury (TBI) on hearing loss and hearing difficulty from the Noise Outcomes in Servicemembers Epidemiology (NOISE) study. Cross-sectional. Multi-institutional tertiary referral centers. Four hundred seventy-three Active-Duty Service members (ADSM) and 502 veterans. Self-reported history of no TBI, military TBI only, nonmilitary TBI only, both military and nonmilitary TBI. Pure-tone hearing thresholds, Speech Recognition In Noise Test (SPRINT), Hearing Handicap Inventory for Adults (HHIA), and Speech, Spatial and Qualities of Hearing Scale (SSQ)-12. 25% (120/473) of ADSM and 41% (204/502) of veterans self-reported a TBI. Military TBI was associated with poorer hearing thresholds in all frequency ranges in veterans (adjusted mean difference, 1.8 dB; 95% confidence interval [CI], 0.5-3.0; 3.3, 0.8-5.8; 5.1; 1.7-8.5, respectively), and in the high frequency range in ADSM (mean difference, 3.2 dB; 95% CI, 0.1-6.3). Veterans with military TBI only and nonmilitary TBI only had lower odds of correctly identifying speech in noise than veterans with no TBI (odds ratio [OR], 0.78; 95% CI, 0.72-0.83; 0.90; 0.84-0.98). ADSM with a military TBI (OR, 5.7; 95% CI, 2.6-12.5) and veterans with any TBI history (OR, 2.5; 95% CI, 1.5-4.3; OR, 2.2; 95% CI, 1.3-3.8; OR, 4.5; 95% CI, 2.1-9.8) were more likely to report hearing difficulty on HHIA. SSQ-12 results corroborated HHIA findings. Military TBI was associated with poorer hearing thresholds in veterans and ADSM, and poorer SPRINT scores in veterans. Military TBI was associated with poorer self-perceived hearing ability in ADSM. All types of TBI were associated with poorer self-perceived hearing ability in veterans, although the strength of this association was greatest for military TBI.

Longitudinal observations of the effects of ischemic stroke on binaural perception.

Acute ischemic stroke, characterized by a localized reduction in blood flow to specific areas of the brain, has been shown to affect binaural auditory perception. In a previous study conducted during the acute phase of ischemic stroke, two tasks of binaural hearing were performed: binaural tone-in-noise detection, and lateralization of stimuli with interaural time- or level differences. Various lesion-specific, as well as individual, differences in binaural performance between patients in the acute phase of stroke and a control group were demonstrated. For the current study, we re-invited the same group of patients, whereupon a subgroup repeated the experiments during the subacute and chronic phases of stroke. Similar to the initial study, this subgroup consisted of patients with lesions in different locations, including cortical and subcortical areas. At the group level, the results from the tone-in-noise detection experiment remained consistent across the three measurement phases, as did the number of deviations from normal performance in the lateralization task. However, the performance in the lateralization task exhibited variations over time among individual patients. Some patients demonstrated improvements in their lateralization abilities, indicating recovery, whereas others' lateralization performance deteriorated during the later stages of stroke. Notably, our analyses did not reveal consistent patterns for patients with similar lesion locations. These findings suggest that recovery processes are more individual than the acute effects of stroke on binaural perception. Individual impairments in binaural hearing abilities after the acute phase of ischemic stroke have been demonstrated and should therefore also be targeted in rehabilitation programs.

The reverse stethoscope technique: a rapid intervention for old age hearing loss

ABSTRACT Objectives Presbycusis is highly prevalent, affecting between a third and two-thirds of elderly populations. Effective communication between patient and physician has been shown to directly correlate with the quality of patient care. The Reverse Stethoscope Technique (RST) involves placing the earpieces into the patient’s ears and speaking into the diaphragm. Here, we aim to show the RST is a simple and effective method to communicate with patients suffering from presbycusis in inpatient settings. Methods Medical inpatients aged >60 years old without cognitive impairment were included in the study. A simple repetition exercise of basic English sentences was performed with and without the RST to assess hearing ability. Patients then undertook a short questionnaire. Results Our study included 109 patients with varied ‘self-reported’ hearing. 50.5% of our cohort reported past communication difficulties with health-care professionals due to hearing difficulties. We identified that the RST increased the mean number of sentences a patient could repeat from 2.6 to 3.5 representing a statistically significant increase (p < 0.001). The technique was most beneficial for patients with ‘okay’ and ‘poor’ hearing. The majority of patients (77/109) also stated the technique reduced background noise. The RST was equally effective with facemasks. Conclusion Current techniques to enhance communication with patients with hearing loss are often underutilized or poorly accessible. Our study identified that the RST is a quick and effective solution that can be easily implemented for patients struggling to communicate with health-care professionals in inpatient scenarios.

Design of efficient alterable bandwidth FIR filterbank for hearing aid system

The lifestyle of any person depends on his ability to hear his surrounding sounds or voices. This is because each of our sense organs works interrelated. Without an ability to proper hearing, he/she cannot respond to the other person leading to a very less or no communication to the society. Although he has a good talent and knowledge within, he cannot be able to communicate or express unless he has a good hearing ability. Also, he faces emotive problems caused by a reduction in self-confidence. So, a requirement of designing an efficient hearing aid is much necessary to resolve the hearing loss problem. In this paper, design of an efficient alterable ten band Finite Impulse Response filter bank for the hearing aid is achieved. Among the various windowing techniques available, Hamming window is preferred to design the FIR filter owing to its relatively sharp main lobe width and also the first few lobes have good attenuation. In this filterbank, variability in the subband bandwidths is achieved by simply altering each subband's bandwidth and center frequency. Unlike fixed filterbank, the proposed design provides the advantage of matching most of the audiograms of different hearing-impaired persons more accurately with simple procedure leading to low cost and low hardware complexity. Also using an FIR filter in the filterbank leads to highly stable design. Thus, a design of highly qualitative filterbank compared to fixed bandwidth designs with high audiogram matching and less matching error is implemented.

Results from 228 Patients with Hemifacial Spasm Undergoing Microvascular Decompression without Intraoperative Neuroelectrophysiology Monitoring

IntroductionIntraoperative neuroelectrophysiology monitoring (IONM) has been used to decrease complications and to increase the successful rate of microvascular decompression (MVD) MVD for hemifacial spasm (HFS). Still, it is not available at limited resource centers. We report the outcome of patients undergoing MVD for HFS without using IONM. Materials and MethodThe variables concerning the patients' demographics (age and gender), clinical characteristics, offending vessels (vertebral artery type and non-vertebral artery type), postoperative grade of hemifacial spasm, and postoperative complications of HFS patients undergoing MVD were retrospectively reviewed and collected. The scoring system provided by the Japan Society for MVD was used to evaluate the postoperative outcome of HFS. Postoperative hearing ability was evaluated according to a subjective assessment of the patients. ResultsA total of 228 patients were recruited. Their median age was 51.0 (44.0-57.0) years old. The total cure effect was observed in 207 (90.8%) patients within the first week after the surgery and in 200 (96.1%) patients in a 2-year follow-up. Permanent hearing disturbance happened in 2 patients (0.9%). No patient had permanent unilateral deafness (0%). No postoperative permanent facial paralysis was reported. ConclusionMVD without IONM may be performed safely and effectively to treat patients with HFS.

Pros and cons of a bone-conduction device implanted in the worse hearing ear of patients with asymmetric hearing loss

PurposeBone-conduction devices can be considered a viable treatment option for patients experiencing asymmetric hearing loss (AHL), especially those with severe to profound hearing loss (HL) present in one ear. However, there are only a few reports on the effects of bone-anchored hearing aids (BAHAs) on patients with AHL. This retrospective study analyzed in detail the effects of BAHA on softer sounds than other hearing aids and identified situations in which BAHA had a negative effect.MethodsPatients with AHL, characterized by severe to profound hearing loss in one ear with a difference of ≥45 dB from that of the contralateral ear, underwent BAHA implantation in the ear with worse hearing. The BAHA effects were evaluated by assessing the word recognition score (WRS) and speech reception threshold (SRT) using the Japanese Oldenburg Sentence Test for various signal settings and noise directions. For a subjective analysis, the Speech, Spatial and Qualities of Hearing Scale (SSQ12) score was determined.ResultsThirteen patients who underwent BAHA implantation at the Miyazaki University Hospital between 2007 and 2021 were included. The BAHA demonstrated a significant improvement in the WRS from 40 to 70 dB sound pressure levels. Although the SRT showed significant improvement in noisy environments when speech was presented to the BAHA-wearing side, it worsened significantly when noise was presented to this side. In the survey of subjective hearing ability, both the total and subscale SSQ12 scores improved significantly after wearing the BAHA.ConclusionThis study identified scenarios in which BAHAs were beneficial and detrimental to individuals with AHL. Generally used audiological tests, such as the WRS with fixed sound pressure, may underestimate the effectiveness of BAHAs for softer sounds. In addition, depending on the direction of the noise, BAHAs may have adverse effects. These results could help patients comprehend the potential benefits and limitations of bone-conduction devices for their hearing.

PSYCHO-SOCIAL CHALLENGES FACED BY SENIOR CITIZENS –CASE STUDY ANALYSIS

The geriatric population of India keeps increasing because of medical advancements in ageing. The senior citizens face lot of psycho-social challenges which includes rejection by their own children, various forms of abuses, loneliness, being uncared of their illnesses and left unloved. The list goes on. The researcher selected a specific Old age home in Madurai, to study the psycho-social challenges faced by the Senior Citizens inspite of providing them food, clothing and shelter along with medical needs they require. The researcher adopted Explanatory Case Study design put forth by Robert K Yin (2003) and did the case study among two cases. The case study analysis was done by the researcher and the case study is presented using Brian Budgell (2008) methodology for the case study presentation. Interview was the technique used by the researcher to collect data. It was found that the cases were having interpersonal relationship problem, adjustmental problem, health issues like hyper tension and diabetes, Social isolation, forgetfulness and decrease in hearing ability. The researcher suggests through the case study analysis, to help senior citizens feel better by providing proper caregivers, enhancing family support and by adopting certain social work interventions to reduce their stress.

Auditory Profile-Based Hearing Aid Fitting: Self-Reported Benefit for First-Time Hearing Aid Users.

Background: Although hearing aids (HAs) can compensate for reduced audibility, functional outcomes and benefits vary widely across individuals. As part of the Danish 'Better hEAring Rehabilitation' (BEAR) project, four distinct auditory profiles differing in terms of audiometric thresholds and supra-threshold hearing abilities were recently identified. Additionally, profile-specific HA-fitting strategies were proposed. The aim of the current study was to evaluate the self-reported benefit of these profile-based HA fittings in a group of new HA users. Methods: A total of 205 hearing-impaired older adults were recruited from two Danish university hospitals. Participants were randomly allocated to one of two treatment groups: (1) NAL-NL2 gain prescription combined with default advanced feature settings ('reference fitting') or (2) auditory profile-based fitting with tailored gain prescription and advanced feature settings ('BEAR fitting'). Two months after treatment, the participants completed the benefit version of the short form of the Speech, Spatial, and Qualities of Hearing Scale (SSQ12-B) and the International Outcome Inventory for Hearing Aids (IOI-HA) questionnaire. Results: Overall, participants reported a clear benefit from HA treatment. However, no significant differences in the SSQ12-B or IOI-HA scores between the reference and BEAR fittings were found. Conclusion: First-time users experience clear benefits from HA treatment. Auditory profile-based HA fitting warrants further investigation.

Survey Paper - Sign Language Detection and Conversion using Deep Learning

Abstract: Communication for the deaf and mute relies on intricate gestures and visual cues, presenting a challenge for accurate interpretation. This project employs advanced deep learning techniques, utilizing SVM and K-means Clustering algorithms for precise real-time recognition of these expressions from images. Our aim is to bridge the communication gap, empowering the hearing-impaired to engage meaningfully and be a vital part of human interaction. Through this innovative approach, we create an inclusive society where everyone can express themselves effectively, regardless of their hearing abilities.

Community Communication in Realizing Inclusive Education for People with Disabilities: Description of UMJ Disabled Care Community

Physical limitations are not one of the obstacles for people with disabilities in carrying out activities, but facilities and infrastructure that are important for their lives. The spirit embedded in continuing education forms a motivation in them to always try their best in seeking knowledge. Agencies or institutions that provide educational facilities for those with special needs generate attention and attract their own interest to people with disabilities. This study aims to see the support and obstacles felt by people with disabilities regarding campus life in inclusive education. Descriptive qualitative methods using interview, observation and field study techniques became the basis for the formation of this research. Inclusive education is one of the important means for people with disabilities in carrying out learning activities, the availability of various facilities makes them feel the same opportunities as other students. However, this research resulted in people with disabilities, especially the blind, still finding it difficult with the unavailability of guiding blocks in the campus area of the University of Muhammadiyah Jakarta, so they need friends or companions to access or visit every corner of the campus. In addition, increasingly advanced technology provides online learning. It is also a challenge for blind people with disabilities by relying on their hearing ability to absorb every knowledge provided. The needs for people with disabilities, especially the blind, are means of information, achievements in academic and non-academic and also companions. Then, in terms of inclusive education, students with disabilities and non-disabilities will build mutually beneficial relationships so that communication between them will be established by understanding each other and the form of inclusive education can be carried out in accordance with its goals

Effect of COVID-19 on peripheral and central hearing abilities

BackgroundCOVID-19 has caused various implications on physical and mental health of human beings. It included several symptoms involving the auditory vestibular system. This study aims to investigate the impact of active COVID-19 infection on central and peripheral auditory pathways.MethodTwo groups of subjects were involved in the research: Group I consisted of 45 individuals with no history of COVID-19, while Group II included 41 individuals who were diagnosed with COVID-19 through RT-PCR testing.The audiological battery used in this study included Pure tone audiometry, Digit in Noise test, Dichotic CV test, and Pitch pattern test, all of which were administered online. Testing was conducted in two phases for both groups. Phase 1 testing took place within the first 7 days of a positive RT-PCR result, while Phase 2 testing occurred within a week of a negative RT-PCR test. Additionally, participants completed a questionnaire to provide information on general health conditions and their otological symptoms.ResultsThe results from Phase 1 testing revealed that Group II exhibited statistically lower scores in all the audiological tests compared to Group I (control group). However, during Phase 2 testing, this significant difference was no longer observed between both groups.ConclusionBased on the findings, it can be inferred that the audiological pathway was compromised during the active infection stage of COVID-19. Therefore, this study highlights changes in performance concerning tests that assess the central auditory system during the infection period.Trial registrationSH/IRB/RP/24. Registered 12 January 2021.

Evaluation of a non-auditory neurocognitive test battery in hearing-impaired according to age.

Due to the demographic shift, the number of older people suffering from hearing loss and from cognitive impairment increases. Both are closely related and hard to differentiate as most standard cognitive test batteries are auditory-based and hearing-impaired individuals perform worse also in non-auditory test batteries. Therefore, reference data for hearing-impaired are mandatory. The computer-based battery ALAcog assesses multiple cognitive domains, such as attention, (delayed) memory, working memory, inhibition, processing speed, mental flexibility and verbal fluency. A data set of 201 bilaterally hearing-impaired subjects aged ≥ 50 (mean 66.6 (SD 9.07)) was analysed. The LMS method, estimated curves for the 10th, 25th, 50th, 75th and 90th percentile were calculated, and classified according to age, starting from the age of 50. Cognitive function shows a decline in all subtests as people age, except for verbal fluency, which remains almost stable over age. The greatest declines were seen in recall and delayed recall and in mental flexibility. Age and hearing ability did not correlate (p = 0.68). However, as people age, inter-subject variability of cognitive test results increases. This was especially the case for inhibition. Cognitive function was not correlated with hearing ability (each p ≥ 0.13). The present results make an approach to establish reference data for a comprehensive non-auditory test battery in a large sample of elderly hearing-impaired people which can be used as a simple tool to better contextualise cognitive performance beyond mean and median scores.

The challenge of a mature final diagnosis of hearing loss severity and early cochlear implantation.

Despite the recent trend of cochlear implantation (CI) at the age of six or even four months is prevalent in many centers around the world, clinicians should be cautious because perinatal risk factors of auditory neuropathy and/or delayed maturation carry the possibility of reversible hearing loss, yielding better auditory performance at the age of one year. The purpose of this study is to raise awareness that early CI may not be universal for all patients. In addition, we specify the factors to be considered in the pre-operative evaluation of CI in infants younger than one year. This study describes four cases provisionally diagnosed with severe to profound sensorineural hearing loss that were presented to the CI clinic to determine candidacy for implantation. Two cases had histories of prematurity, one hadDown syndrome, and one had a family history of hearing loss. None of the study cases were candidates for CI, as they had varying degrees of hearing improvement. Although early CI may yield better auditory performance, the final diagnosis should be made only after repeated subjective and objective measurements as well as family feedback on the child's auditory performance, especially in preterm children. Early auditory brainstem response (ABR) prior to the age of one year in children with cognitive, neurologic, or developmental comorbidities should be interpreted with caution, as ABR "alone" could not accurately represent the child's true hearing ability in this patient population.

Amer1 Regulates Zebrafish Craniofacial Development by Interacting with the Wnt/β-Catenin Pathway.

Microtia-atresia is a rare type of congenital craniofacial malformation causing severe damage to the appearance and hearing ability of affected individuals. The genetic factors associated with microtia-atresia have not yet been determined. The AMER1 gene has been identified as potentially pathogenic for microtia-atresia in two twin families. An amer1 mosaic knockdown zebrafish model was constructed using CRISPR/Cas9. The phenotype and the development process of cranial neural crest cells of the knockdown zebrafish were examined. Components of the Wnt/β-catenin pathway were examined by qPCR, Western blotting, and immunofluorescence assay. IWR-1-endo, a reversible inhibitor of the Wnt/β-catenin pathway, was applied to rescue the abnormal phenotype. The present study showed that the development of mandibular cartilage in zebrafish was severely compromised by amer1 knockdown using CRISPR/Cas9. Specifically, amer1 knockdown was found to affect the proliferation and apoptosis of cranial neural crest cells, as well as their differentiation to chondrocytes. Mechanistically, amer1 exerted an antagonistic effect on the Wnt/β-catenin pathway. The application of IWR-1-endo could partially rescue the abnormal phenotype. We demonstrated that amer1 was essential for the craniofacial development of zebrafish by interacting with the Wnt/β-catenin pathway. These findings provide important insight into the role of amer1 in zebrafish mandibular development and the pathology of microtia-atresia caused by AMER1 gene mutations in humans.

The effect of occupational exposure to noise and chemical agents on hearing abilities

Exposure to loud noise or chemical agents may cause hearing disorders such as tinnitus and recruitment, known as an increase in the perception of loudness in addition to hearing loss. Our study aims to evaluate the hearing abilities of hairdressers exposed to noise and chemical agents in the working environment. The study included one hundred hairdressers and one hundred participants who do not work as hairdressers or are nonworkers. The participants’ demographic characteristics, working conditions, and auditory complaints were questioned, and each participant completed the Speech, Spatial, and Qualities of Hearing Scale (SSQ). A statistically significant difference was found between the two groups in speech perception, spatial perception, hearing quality, and general SSQ scores. Hairdressers’ SSQ scores were significantly lower in all sub-dimensions and general scale scores (p < 0.001). The auditory complaints of the hairdressers and the low SSQ scores indicate that exposure to noise and chemical agents affects the hairdressers’ hearing system.