Loud Music and Leisure Noise Is a Common Cause of Chronic Hearing Loss, Tinnitus and Hyperacusis

Recreational music exposure and hearing health in young adults

OBJECTIVE

This study aimed to compare daily and total recreational music exposure levels and extended-spectrum audiogram results in young adults without pre-existing hearing problems.

DESIGN

The study included healthy volunteers aged 18-25 with no known ear disease or hearing loss. Participants completed a questionnaire, underwent otoscopic and tympanometric examinations, and determined preferred music volumes in an audiometry booth using calibrated music samples of their preferred genres. Hearing thresholds up to 16 kiloHertz (kHz) were measured. Daily music exposure for each participant was normalized to 8 h to calculate a time-weighted average of 8 h (TWA8). Total exposure (TE) was calculated by multiplying TWA8 by the number of years of music listening.

RESULTS

A total of 32.4% of participants had TWA8s above 65 dB. Their hearing thresholds at 125, 250, 500, and 16,000 Hz and the average of 125 Hz-8 kHz were significantly higher. Participants with TWA8s above 65 dB were also more prone to speaking loudly and experiencing communication difficulties on the phone. Those with a TE of more than 400 experienced significantly more speech discrimination difficulty in noisy environments and temporary hearing loss/tinnitus after exposure to loud music. Participants with a TE above 700 had worse thresholds at 4, 14, and 16 kHz frequencies, as well as 125-8000 Hz and 500-4000 Hz averages compared to those with a TE below 700.

CONCLUSIONS

This study provides evidence that recreational music with much lower exposure levels than the universally accepted TWA8 of 85 dB could negatively impact hearing in healthy young adults. Therefore, maintaining a maximum TWA8 of 65 dB is recommended.

Advancing noise management in aviation: Strategic approaches for preventing noise-induced hearing loss

As urbanization and population growth escalate, the challenge of noise pollution intensifies, particularly within the aviation industry. This review examines current insights into noise-induced hearing loss (NIHL) in aviation, highlighting the risks to pilots, cabin crew, aircraft maintenance engineers, and ground staff from continuous exposure to high-level noise. It evaluates existing noise management and hearing conservation strategies, identifying key obstacles and exploring new technological solutions. While progress in developing protective devices and noise control technologies is evident, gaps in their widespread implementation persist. The study underscores the need for an integrated strategy combining regulatory compliance, technological advances, and targeted educational efforts. It advocates for global collaboration and policy development to safeguard the auditory health of aviation workers and proposes a strategic framework to enhance hearing conservation practices within the unique challenges of the aviation sector.

Ten-year results of leisure noise exposure among adolescents and young adults-findings from the OHRKAN cohort study

OBJECTIVE

To observe total leisure noise (TLN) exposure and to investigate determinants of risky TLN exposure among adolescents and young adults over a ten-year observation period.

DESIGN

OHRKAN is a longitudinal study with five equidistantly distributed questionnaires (waves) over ten years. Risky TLN exposure was defined as exceeding ≥85dB(A) averaged over 40h per week. To identify determinants of risky TLN exposure longitudinally, generalised estimating equations were applied.

STUDY SAMPLE

A subgroup (n = 661; mean age 25.6 years in the fifth wave; 58.4% female) of the closed cohort study OHRKAN was analysed. Included participants took part in the fifth wave prior to the study break due to COVID-19.

RESULTS

Analysis of participants' data from all five waves showed that risky TLN exposure was highest during the second wave (72.0%), when participants were aged 17-19 years, and thereafter steadily declined. Among young adults, attendance at discotheques and private parties, especially, caused very high exposure. Determinants of risky TLN exposure were wave time point, male gender, a higher level of education, and smoking.

CONCLUSIONS

As TLN exposure is highest among older adolescents, prevention programs should target younger teenagers and be tailored to the identified risk groups. The risk from private parties should be addressed.

Risk of noise-induced hearing loss in the spine surgeon

Background

Occupation-related noise-induced hearing loss (NIHL) has both negative economic and quality of life implications. The risk spine surgeons undertake in regards to NIHL during operative intervention is unknown. Governing bodies, including the National Institute for Occupational Safety and Health, have recommended exposure limits not to exceed 85 decibels (dB) over 8 hours. The purpose of this study is to characterize noise exposure to spine surgeons in the operating room (OR).

Methods

Prospective collection of intraoperative recordings of spinal surgeries (cervical and thoracic/lumbar) was undertaken. Data gathered included procedure, operative duration, presence of background music, and noise information. Noise information included maximum decibel level (MDL), Peak level (LCPeak), Equivalent continuous sound pressure level, time weighted average (TWA), dose, and projected dose. Noise measurements were compared with baseline controls with and without music (empty ORs).

Results

Two hundred seven noise recordings were analyzed. One hundred eighteen of those being spinal surgeries, 49 baseline recordings without music, and 40 with music. Maximum decibel level reached a maximum value of 111.5 dBA, with an average amongst surgical recordings of 103 dBA. Maximum decibel level exceeded 85 dBA in 100% of cases and was greater than 100 dBA in 78%. The maximum LCPeak recorded was 132.9 dBC with an average of 120 dBC. Furthermore, the average dose was 7.8% with an average projected dose of 26.5%. The highest dose occurred during a laminectomy at 72.9% of daily allowable noise. Maximum projected dose yielded 156% during a 3-level anterior cervical discectomy and fusion.

Conclusions

Spine surgeons are routinely exposed to damaging noise levels (>85 dBA) during operative intervention. With spine surgeons often performing multiple surgeries a day, the cumulative risk of noise exposure cannot be ignored. The synergistic effects of continuous and impact noise places spine surgeons at risk for the development of occupation-related NIHL.

The sound of safety: exploring the determinants of prevention intention in noisy industrial workplaces

Occupational noise exposure is a pervasive issue in many industries, leading to a range of health issues and sleep disturbances among workers. Additionally, there is a strong desire among these workers to prevent industrial accidents. This study, aimed at enhancing worker health and well-being, utilized a survey distributed by the Korean Confederation of Trade Unions to field workers. Data from 1285 workers were collected and analyzed using partial least squares structural equation modeling (PLS-SEM) to identify and understand the factors affecting prevention intention in noisy work environments. Our findings indicate that health problems resulting from occupational noise exposure significantly influence insomnia, perceived severity of potential accidents, perceived benefits of preventive measures, and perceived barriers. Perceived severity was significantly correlated with prevention intention, emphasizing the role of risk perception in motivating preventive behaviors. Perceived benefits were also significantly associated with prevention intention, highlighting the importance of positive outcomes in influencing workers' behaviors. Additionally, perceived barriers showed a significant relationship with prevention intention, suggesting that overcoming these barriers is crucial in promoting preventive behaviors. Demographic factors such as gender displayed a significant association with prevention intention, while age did not. This study provides valuable insights into the multifaceted factors influencing workers' intention to prevent industrial accidents in noisy environments, underlining the importance of comprehensive data collection tools in understanding these dynamics.

Blast Overpressures as a Military and Occupational Health Concern

PURPOSE

This tutorial reviews effects of environmental stressors like blast overpressures and other well-known acoustic contaminants (continuous, intermittent, and impulsive noise) on hearing, tinnitus, vestibular, and balance-related functions. Based on the overall outcome of these effects, detailed consideration is given to the health and well-being of individuals.

METHOD

Because hearing loss and tinnitus are consequential in affecting quality of life, novel neuromodulation paradigms are reviewed for their positive abatement and treatment-related effects. Examples of clinical data, research strategies, and methodological approaches focus on repetitive transcranial magnetic stimulation (rTMS) and electrical stimulation of the vagus nerve paired with tones (VNSt) for their unique contributions to this area.

RESULTS

Acoustic toxicants transmitted through the atmosphere are noteworthy for their propensity to induce hearing loss and tinnitus. Mounting evidence also indicates that high-level rapid onset changes in atmospheric sound pressure can significantly impact vestibular and balance function. Indeed, the risk of falling secondary to loss of, or damage to, sensory receptor cells in otolith organs (utricle and saccule) is a primary reason for this concern. As part of the complexities involved in VNSt treatment strategies, vocal dysfunction may also manifest. In addition, evaluation of temporospatial gait parameters is worthy of consideration based on their ability to detect and monitor incipient neurological disease, cognitive decline, and mortality.

CONCLUSION

Highlighting these respective areas underscores the need to enhance information exchange among scientists, clinicians, and caregivers on the benefits and complications of these outcomes.

The development and evaluation of an online hearing loss prevention program

Recent studies underline the need for research on approaches to encouraging healthy listening habits. This study aims to develop and evaluate an online hearing loss prevention program; and examine its influence on the participants' use of hearing protection, hearing loss prevention knowledge, attitude towards noise, and program useability and adherence. The study was conducted in the county of Västra Götaland, Sweden, from March through October 2021. The program included four modules focused on hearing and hearing loss prevention and was accessible to the participants for four weeks. In total, 75 participants completed the program which was evaluated using the Youth Attitude to Noise Scale and four additional self-designed questionnaires. The questionnaires were deployed before and immediately after program completion. The findings indicate that the program may influence the participants' attitudes toward noise and the use of hearing protection. The participants who completed the program perceived high useability and increased hearing loss prevention knowledge. This program is most needed to promote healthy hearing. Future studies should target specific groups with this program and evaluate its long-term effects.

Noise Exposure in Palestinian Workers Without a Diagnosis of Hearing Impairment: Relations to Speech-Perception-in-Noise Difficulties, Tinnitus, and Hyperacusis

PURPOSE

Many workers in developing countries are exposed to unsafe occupational noise due to inadequate health and safety practices. We tested the hypotheses that occupational noise exposure and aging affect speech-perception-in-noise (SPiN) thresholds, self-reported hearing ability, tinnitus presence, and hyperacusis severity among Palestinian workers.

METHOD

Palestinian workers (N = 251, aged 18-70 years) without diagnosed hearing or memory impairments completed online instruments including a noise exposure questionnaire; forward and backward digit span tests; hyperacusis questionnaire; the short-form Speech, Spatial and Qualities of Hearing Scale (SSQ12); the Tinnitus Handicap Inventory; and a digits-in-noise (DIN) test. Hypotheses were tested via multiple linear and logistic regression models, including age and occupational noise exposure as predictors, and with sex, recreational noise exposure, cognitive ability, and academic attainment as covariates. Familywise error rate was controlled across all 16 comparisons using the Bonferroni-Holm method. Exploratory analyses evaluated effects on tinnitus handicap. A comprehensive study protocol was preregistered.

RESULTS

Nonsignificant trends of poorer SPiN performance, poorer self-reported hearing ability, greater prevalence of tinnitus, greater tinnitus handicap, and greater severity of hyperacusis as a function of higher occupational noise exposure were observed. Greater hyperacusis severity was significantly predicted by higher occupational noise exposure. Aging was significantly associated with higher DIN thresholds and lower SSQ12 scores, but not with tinnitus presence, tinnitus handicap, or hyperacusis severity.

CONCLUSIONS

Workers in Palestine may suffer from auditory effects of occupational noise and aging despite no formal diagnosis. These findings highlight the importance of occupational noise monitoring and hearing-related health and safety practices in developing countries.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22056701.

Systematic analysis to identify novel disease indications and plausible potential chemical leads of glutamate ionotropic receptor NMDA type subunit 1, GRIN1

Schizophrenia is a mental illness affecting the normal lifestyle of adults and early adolescents incurring major symptoms as jumbled speech, involvement in everyday activities eventually got reduced, patients always struggle with attention and memory, reason being both the genetic and environmental factors responsible for altered brain chemistry and structure, resulting in schizophrenia and associated orphan diseases. The network biology describes the interactions among genes/proteins encoding molecular mechanisms of biological processes, development, and diseases. Besides, all the molecular networks, protein-protein Interaction Networks have been significant in distinguishing the pathogenesis of diseases and thereby drug discovery. The present meta-analysis prioritizes novel disease indications viz. rare and orphan diseases associated with target Glutamate Ionotropic Receptor NMDA Type Subunit 1, GRIN1 using text mining knowledge-based tools. Furthermore, ZINC database was virtually screened, and binding conformation of selected compounds was performed and resulted in the identification of Narciclasine (ZINC04097652) and Alvespimycin (ZINC73138787) as potential inhibitors. Furthermore, docked complexes were subjected to MD simulation studies which suggests that the identified leads could be a better potential drug to recuperate schizophrenia.

The association between stress, emotional states, and tinnitus: a mini-review

Extensive literature supporting the view of tinnitus induced stress in patients is available. However, limited evidence has been produced studying the opposite, that is, does stress cause tinnitus? The hypothalamus pituitary adrenal axis, one of the main neuroendocrine systems involved in stress response, is commonly disturbed in tinnitus patients. Patients with chronic tinnitus have been shown to develop abnormal responses to psycho-social stress, where the hypothalamus pituitary adrenal axis response is weaker and delayed, suggesting chronic stress contributes to the development of chronic tinnitus. The sympathetic branch of the autonomic nervous system also plays a major role in stress response and its chronic hyperactivity seems to be involved in developing tinnitus. Psycho-social stress has been shown to share the same probability of developing tinnitus as occupational noise and contributes to worsening tinnitus. Additionally, exposure to high stress levels and occupational noise doubles the likelihood of developing tinnitus. Interestingly, short-term stress has been shown to protect the cochlea in animals, but chronic stress exposure has negative consequences. Emotional stress also worsens pre-existing tinnitus and is identified as an important indicator of tinnitus severity. Although there is limited body of literature, stress does seem to play a vital role in the development of tinnitus. This review aims to highlight the association between stress, emotional states, and the development of tinnitus while also addressing the neural and hormonal pathways involved.

Sound Therapy to Reduce Auditory Gain for Hyperacusis and Tinnitus

Purpose:

Hyperacusis is the most common of the different types of sound tolerance conditions. It has been defined as physical discomfort or pain when any sound reaches a certain level of loudness that would be comfortable for most people. Because hyperacusis and tinnitus occur together so often, it has been theorized that they have a common neural mechanism. A leading contender for that mechanism is enhancement of auditory gain. The purpose of this tutorial is to review the evidence that sound/acoustic therapy can reduce auditory gain and, thereby, can increase loudness tolerance for people with hyperacusis and/or suppress the percept of tinnitus.

Method:

The scientific literature was informally reviewed to identify and elucidate relationships between tinnitus, hyperacusis, sound therapy, and auditory gain.

Results:

Evidence exists, both in animal and human studies, that enhanced auditory gain is associated with hyperacusis and tinnitus. Further evidence supports the theory that certain forms of sound therapy can reduce neural hyperactivity, thereby reducing auditory gain. The evidence for sound therapy reducing auditory gain is stronger for hyperacusis than it is for tinnitus.

Conclusions:

Based on results from numerous studies, sound therapy clearly has application as a method of desensitization for hyperacusis. Enhanced auditory gain might be responsible for tinnitus, but other mechanisms have been theorized. A review of the relevant literature leads to the conclusion that some form(s) of sound therapy has the potential to suppress or eliminate tinnitus on a long-term basis. Systematic research is needed to evaluate this premise.

Prevalence and global estimates of unsafe listening practices in adolescents and young adults: a systematic review and meta-analysis

INTRODUCTION

This study aimed to determine the prevalence of unsafe listening practices from exposure to personal listening devices (PLDs) and loud entertainment venues in individuals aged 12-34 years, and to estimate the number of young people who could be at risk of hearing loss from unsafe listening worldwide.

METHODS

We conducted a systematic review and meta-analysis to estimate the prevalence of unsafe listening practices from PLDs and loud entertainment venues. We searched three databases for peer-reviewed articles published between 2000 and 2021 that reported unsafe listening practices in individuals aged 12-34 years. Pooled prevalence estimates (95% CI) of exposed populations were calculated using random effects models or ascertained from the systematic review. The number of young people who could be at risk of hearing loss worldwide was estimated from the estimated global population aged 12-34 years, and best estimates of exposure to unsafe listening ascertained from this review.

RESULTS

Thirty-three studies (corresponding to data from 35 records and 19 046 individuals) were included; 17 and 18 records focused on PLD use and loud entertainment venues, respectively. The pooled prevalence estimate of exposure to unsafe listening from PLDs was 23.81% (95% CI 18.99% to 29.42%). There was limited certainty (p>0.50) in our pooled prevalence estimate for loud entertainment venues. Thus, we fitted a model as a function of intensity thresholds and exposure duration to identify the prevalence estimate as 48.20%. The global estimated number of young people who could be at risk of hearing loss from exposure to unsafe listening practices ranged from 0.67 to 1.35 billion.

CONCLUSIONS

Unsafe listening practices are highly prevalent worldwide and may place over 1 billion young people at risk of hearing loss. There is an urgent need to prioritise policy focused on safe listening. The World Health Organization provides comprehensive materials to aid in policy development and implementation.

New Indicators for the Assessment and Prevention of Noise Nuisance

At present, health effects induced by prolonged noise exposure are widely studied to determine the most spread noise sources and their effects [...]

Useful tools for integrating noise maps about noises other than those of transport, infrastructures, and industrial plants in developing countries: Casework of the Aburra Valley, Colombia

The behavior of environmental noise in developing countries is conditioned by characteristics that are not only linked to transport, infrastructures, and industrial plants in the annuity (common representation in noise maps), but also to other types of sources and periodicities that can influence significantly in noise levels. For this reason, this work proposes different temporal analyzes during the annuity that can be linked to the noisy activities typical of developing tropical countries. To do this, a noise monitoring network composed of seven monitors representing different sources present in the Aburrá Valley (AV) in Colombia is analyzed with measurements of LAeq, every hour, in a period between August 2016 and July 2019. The results show that AV noise is strongly influenced by leisure activities related to high-power sound systems, different celebrations, and continuous noise from car traffic that affect the population mainly on weekends and nights. This work marks a clear path to precisely address noise pollution in the action plans of developing countries.

Hearing loss drug discovery and medicinal chemistry: Current status, challenges, and opportunities

Hearing loss is a severe high unmet need condition affecting more than 1.5 billion people globally. There are no licensed medicines for the prevention, treatment or restoration of hearing. Prosthetic devices, such as hearing aids and cochlear implants, do not restore natural hearing and users struggle with speech in the presence of background noise. Hearing loss drug discovery is immature, and small molecule approaches include repurposing existing drugs, combination therapeutics, late-stage discovery optimisation of known chemotypes for identified molecular targets of interest, phenotypic tissue screening and high-throughput cell-based screening. Hearing loss drug discovery requires the integration of specialist therapeutic area biology and otology clinical expertise. Small molecule drug discovery projects in the global clinical portfolio for hearing loss are here collated and reviewed. An overview is provided of human hearing, inner ear anatomy, inner ear delivery, types of hearing loss and hearing measurement. Small molecule experimental drugs in clinical development for hearing loss are reviewed, including their underpinning biology, discovery strategy and activities, medicinal chemistry, calculated physicochemical properties, pharmacokinetics and clinical trial status. SwissADME BOILED-Egg permeability modelling is applied to the molecules reviewed, and these results are considered. Non-small molecule hearing loss assets in clinical development are briefly noted in this review. Future opportunities in hearing loss drug discovery for human genomics and targeted protein degradation are highlighted.

The Effect of Lifetime Noise Exposure and Aging on Speech-Perception-in-Noise Ability and Self-Reported Hearing Symptoms: An Online Study

Animal research shows that aging and excessive noise exposure damage cochlear outer hair cells, inner hair cells, and the synapses connecting inner hair cells with the auditory nerve. This may translate into auditory symptoms such as difficulty understanding speech in noise, tinnitus, and hyperacusis. The current study, using a novel online approach, assessed and quantified the effects of lifetime noise exposure and aging on (i) speech-perception-in-noise (SPiN) thresholds, (ii) self-reported hearing ability, and (iii) the presence of tinnitus. Secondary aims involved documenting the effects of lifetime noise exposure and aging on tinnitus handicap and the severity of hyperacusis. Two hundred and ninety-four adults with no past diagnosis of hearing or memory impairments were recruited online. Participants were assigned into two groups: 217 "young" (age range: 18-35 years, females: 151) and 77 "older" (age range: 50-70 years, females: 50). Participants completed a set of online instruments including an otologic health and demographic questionnaire, a dementia screening tool, forward and backward digit span tests, a noise exposure questionnaire, the Khalfa hyperacusis questionnaire, the short-form of the Speech, Spatial, and Qualities of Hearing scale, the Tinnitus Handicap Inventory, a digits-in-noise test, and a Coordinate Response Measure speech-perception test. Analyses controlled for sex and cognitive function as reflected by the digit span. A detailed protocol was pre-registered, to guard against "p-hacking" of this extensive dataset. Lifetime noise exposure did not predict SPiN thresholds, self-reported hearing ability, or the presence of tinnitus in either age group. Exploratory analyses showed that worse hyperacusis scores, and a greater prevalence of tinnitus, were associated significantly with high lifetime noise exposure in the young, but not in the older group. Age was a significant predictor of SPiN thresholds and the presence of tinnitus, but not of self-reported hearing ability, tinnitus handicap, or severity of hyperacusis. Consistent with several lab studies, our online-derived data suggest that older adults with no diagnosis of hearing impairment have a poorer SPiN ability and a higher risk of tinnitus than their younger counterparts. Moreover, lifetime noise exposure may increase the risk of tinnitus and the severity of hyperacusis in young adults with no diagnosis of hearing impairment.

The Relevance of Leisure Noise to Hearing Threshold Shifts: A Longitudinal Analysis Among Adolescents

PURPOSE

The aim of this study was to analyze the association of total leisure noise exposure and hearing threshold shifts over 5 years among adolescents enrolled in the Ohrkan cohort study.

METHOD

The Ohrkan cohort of 2,148 students aged 13-19 years was recruited from 2009 to 2011 and followed up 5 years later. Complete baseline and follow-up reports on exposure and outcome were available for 989 participants. Leisure noise exposure was assessed by questionnaires, and clinical audiometric examinations were performed. Two outcomes were defined: occurrence of the Niskar notch pattern and audiometry showing maximum hearing threshold values at 3, 4, and 6 kHz (both ears). Longitudinal analysis using generalized estimating equations was performed.

RESULTS

High total leisure noise exposure, defined as an energy equivalent of a 40-hr week of > 85 dBA, was estimated for 32.7% of students at baseline and 63.8% at follow-up. A noise notch was observed in 1.1% of adolescents at baseline and 3.3% at follow-up. At baseline, the maximum measured threshold shift was 55 dB, which increased to 85 dB at the follow-up. Longitudinal analysis did not reveal an association between leisure noise exposure and hearing thresholds. Hearing threshold shifts or noise notches were associated with sex, school type, and time point of measurement.

CONCLUSIONS

No relationship was found between leisure noise and hearing thresholds. Male adolescents and those attending secondary general schools, with graduation following completion of ninth or 10th grade, had a greater likelihood of developing hearing threshold shifts. Prevention programs should focus on these risk groups.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19233462.

The α9α10 nicotinic acetylcholine receptor: a compelling drug target for hearing loss?

INTRODUCTION

Hearing loss is a major health problem, impacting education, communication, interpersonal relationships, and mental health. Drugs that prevent or restore hearing are lacking and hence novel drug targets are sought. There is the possibility of targeting the α9α10 nicotinic acetylcholine receptor (nAChR) in the prevention of noise-induced, hidden hearing loss and presbycusis. This receptor mediates synaptic transmission between medial olivocochlear efferent fibers and cochlear outer hair cells. This target is key since enhanced olivocochlear activity prevents noise-induced hearing loss and delays presbycusis.

AREAS COVERED

The work examines the α9α10 nicotinic acetylcholine receptor (nAChR), its role in noise-induced, hidden hearing loss and presbycusis and the possibility of targeting. Data has been searched in Pubmed, the World Report on Hearing from the World Health Organization and the Global Burden of Disease Study 2019.

EXPERT OPINION

The design of positive allosteric modulators of α9α10 nAChRs is proposed because of the advantage of reinforcing the medial olivocochlear (MOC)-hair cell endogenous neurotransmission without directly stimulating the target receptors, therefore avoiding receptor desensitization and reduced efficacy. The time is right for the discovery and development of α9α10 nAChRs targeting agents and high throughput screening assays will support this.

Early detection of noise-induced hearing loss

BACKGROUND

Noise-induced hearing loss (NIHL) is the second most common acquired hearing loss following presbycusis. Exposure to recreational noise and minimal use of hearing protection increase the prevalence of NIHL in young females. NIHL is irreversible. Identifying minor hearing pathologies before they progress to hearing problems that affect daily life is crucial.

AIM

To compare the advantages and disadvantages of extended high frequency (EHF) and otoacoustic emission and determine an indicator of hearing pathologies at the early sub-clinical stage.

METHODS

This cross-sectional study was implemented in West China Hospital of Sichuan University from May to September 2019. A total of 86 participants, aged 18-22 years, were recruited to establish normative thresholds for EHF. Another 159 adults, aged 18-25 years with normal hearing (0.25-8 kHz ≤ 25 dBHL), were allocated to low noise and noise exposure groups. Distortion otoacoustic emission (DPOAE), transient evoked otoacoustic emissions (TEOAE), and EHF were assessed in the two groups to determine the superior technique for detecting early-stage noise-induced pathologies. The chi-square test was used to assess the noise and low noise exposure groups with respect to extended high-frequency audiometry (EHFA), DPOAE, and TEOAE. P ≤ 0.05 was considered statistically significant.

RESULTS

A total of 86 participants (66 females and 20 males) aged between 18 and 22 (average: 20.58 ± 1.13) years were recruited to establish normative thresholds for EHF. The normative thresholds for 9, 10, 11.2, 12.5, 14, 16, 18, and 20 kHz were 15, 10, 20, 15, 15, 20, 28, and 0 dBHL, respectively. A total of 201 participants were recruited and examined for eligibility. Among them, 159 adults aged between 18 and 25 years were eligible in this study. No statistical difference was detected between the noise exposure and the low noise exposure groups using EHFA, DPOAE, and TEOAE (P > 0.05) except in the right ear at 4 kHz using TEOAE (abnormal rate 20.4% vs 5.2%, respectively; P = 0.05).

CONCLUSION

These results showed TEOAE as the earliest indicator of minor pathology compared to DPOAE and EHFA. However, a multicenter controlled study or prospective study is essential to verify these results.