Risk-taking propensity as a risk factor for noise-induced hearing loss in the general population

OBJECTIVES

To examine general risk propensity in relation to perceptions of noise, risk behaviour, and hearing loss in the general population.

DESIGN

Participants completed an online survey using the Amazon Mechanical Turk crowdsourcing platform.

STUDY SAMPLE

The sample comprised 1274 adults from the United States.

RESULTS

Higher general risk propensity was associated with an increased likelihood to engage in noise-risk behaviours. Lower general risk propensity was associated with increased knowledge of noise risks and an increased perception of noise as risky. The frequency of self-reported exposures to hazardous noise resulted in estimated annual noise doses exceeding standard hazard limits in 40% of the surveyed population.

CONCLUSIONS

Results revealed limited knowledge of the risks and associated health consequences of noise exposure in the general population Results of this study suggest a high rate of self-exposure to hazardous noise by the general population. Those with higher general risk propensity are more likely to engage in risky noise behaviour. Risky noise behaviour is associated with age, gender, race, ethnicity, and general risk propensity. Intervention programs to modify risky noise behaviour in the general population should focus on both increasing knowledge and establishing accurate perceptions of risk.

A reliable and reproducible protocol for sound-evoked vestibular myogenic potentials in rattus norvegicus

Introduction

Cervical vestibular evoked myogenic potentials (cVEMPs) provide an objective measure of the integrity of the sacculo-collic pathway leading to their widespread use as a clinical tool in the diagnostic vestibular test battery. Though the application of cVEMPs in preclinical models to assess vestibular function, as performed in relevant clinical populations, remains limited. The present study aimed to establish a rodent model of cVEMP with standardized methods and protocols, examine the neural basis of the responses, and characterize and validate important features for interpretation and assessment of vestibular function.

Methods

We compared air-conducted sound (ACS)-evoked VEMPs from the sternocleidomastoid muscles in naïve Brown Norway rats. A custom setup facilitated repeatable and reliable measurements which were carried out at multiple intensities with ACS between 1 and 16 kHz and over 7 days. The myogenic potentials were identified by the presence of a positive (P1)-negative (N1) waveform at 3-5 ms from the stimulus onset. Threshold, amplitude, and latency were compared with intensity- and frequency-matched responses within and between animals.

Results

cVEMP responses were repeatedly evoked with stimulus intensities between 50-100 dB SPL with excellent test-retest reliability and across multiple measurements over 7 days for all frequencies tested. Suprathreshold, cVEMP responses at 90 dB SPL for 6-10 kHz stimuli demonstrated significantly larger amplitudes (p < 0.01) and shorter latencies (p < 0.001) compared to cVEMP responses for 1-4 kHz stimuli. Latency of cVEMP showed sex-dependent variability, but no significant differences in threshold or amplitude between males and females was observed.

Discussion

The results provide a replicable and reliable setup, test protocol, and comprehensive characterization of cVEMP responses in a preclinical model which can be used in future studies to elucidate pathophysiological characteristics of vestibular dysfunctions or test efficacy of therapeutics.

Contralateral Routing of Signal Disrupts Monaural Sound Localization

OBJECTIVES

In the absence of binaural hearing, individuals with single-sided deafness can adapt to use monaural level and spectral cues to improve their spatial hearing abilities. Contralateral routing of signal is the most common form of rehabilitation for individuals with single-sided deafness. However, little is known about how these devices affect monaural localization cues, which single-sided deafness listeners may become reliant on. This study aimed to investigate the effects of contralateral routing of signal hearing aids on localization performance in azimuth and elevation under monaural listening conditions.

DESIGN

Localization was assessed in 10 normal hearing adults under three listening conditions: (1) normal hearing (NH), (2) unilateral plug (NH-plug), and (3) unilateral plug and CROS aided (NH-plug + CROS). Monaural hearing simulation was achieved by plugging the ear with E-A-Rsoft™ FX™ foam earplugs. Stimuli consisted of 150 ms high-pass noise bursts (3-20 kHz), presented in a random order from fifty locations spanning ±70° in the horizontal and ±30° in the vertical plane at 45, 55, and 65 dBA.

RESULTS

In the unilateral plugged listening condition, participants demonstrated good localization in elevation and a response bias in azimuth for signals directed at the open ear. A significant decrease in performance in elevation occurs with the contralateral routing of signal hearing device on, evidenced by significant reductions in response gain and low r2 value. Additionally, performance in azimuth is further reduced for contralateral routing of signal aided localization compared to the simulated unilateral hearing loss condition. Use of the contralateral routing of signal device also results in a reduction in promptness of the listener response and an increase in response variability.

CONCLUSIONS

Results suggest contralateral routing of signal hearing aids disrupt monaural spectral and level cues, which leads to detriments in localization performance in both the horizontal and vertical dimensions. Increased reaction time and increasing variability in responses suggests localization is more effortful when wearing the contralateral rerouting of signal device.

Prevalence of Hearing Loss and Perceptions of Hearing Health and Protection among Florida Firefighters

Firefighters are exposed to extensive hazardous noise while on the job, both during routine tasks at the station and when responding to calls. However, little is known about firefighters' occupational noise hazards. This study employed mixed methods, including focus groups, a survey, and audiometric testing, to identify sources of noise in the firefighters' work environment, determine hearing protective strategies, discern firefighters' perceptions of occupational noise exposure and impacts to their health, and quantify the prevalence of hearing loss among South Florida firefighters. A total of 6 senior officers served in an expert panel, 12 participated in focus groups, 300 completed the survey, and 214 received audiometric tests. Most firefighters were unaware of the risk and their departments' policies, and did not participate in hearing protection practices and avoided using hearing protection devices, which they believed impede team communication and situational awareness. Nearly 30% of participating firefighters showed mild to profound hearing loss, a prevalence that is considerably worse than expected by normal aging alone. Educating firefighters about noise-induced hearing loss early in their careers may have significant health implications for their future. These findings provide insights for developing technologies and programs to mitigate the effects of noise exposure in the firefighting population.

Monitoring Occupational Noise Exposure in Firefighters Using the Apple Watch

Occupational noise exposure and hearing loss are prominent in the fire service. Firefighters are routinely exposed to hazardous levels of noise arising from the tools and equipment they use, from sirens and alarm tones to the emergency response vehicles they drive. The present study utilized the Apple Watch to continuously measure environmental noise levels for on-duty firefighters. Participants included 15 firefighters from the metropolitan South Florida area, and 25 adult non-firefighter control subjects. Firefighters were recruited from a variety of roles across two stations to ensure noise exposure profiles were appropriately representative of exposures in the fire service. All participants wore an Apple Watch for up to three separate 24 h shifts and completed a post-shift survey self-reporting on perceived exposures over the 24 h study period. Cumulative exposures were calculated for each shift and noise dose was calculated relative to the NIOSH recommended exposure limit of 85 dBA as an 8 h time-weighted average. The maximum dBA recorded on the Apple Watches was statistically significant between groups, with firefighters experiencing a median of 87.79 dBA and controls a median of 77.27 dBA. Estimated Exposure Time at 85 dBA (EET-85) values were significantly higher for firefighters when compared to controls: 3.97 h (range: 1.20-14.7 h) versus 0.42 h (range: 0.05-8.21 h). Only 2 of 16 firefighters reported the use of hearing protection devices during their shifts. Overall, our results highlight the utility of a commonly used personal device to quantify noise exposure in an occupationally at-risk group.

The effects of hearing protection devices on spatial awareness in complex listening environments

Hearing protection devices (HPDs) remain the first line of defense against hazardous noise exposure and noise-induced hearing loss (NIHL). Despite the increased awareness of NIHL as a major occupational health hazard, implementation of effective hearing protection interventions remains challenging in at-risk occupational groups including those in public safety that provide fire, emergency medical, or law enforcement services. A reduction of situational awareness has been reported as a primary barrier to including HPDs as routine personal protective equipment. This study examined the effects of hearing protection and simulated NIHL on spatial awareness in ten normal hearing subjects. In a sound-attenuating booth and using a head-orientation tracker, speech intelligibility and localization accuracy were collected from these subjects under multiple listening conditions. Results demonstrate that the use of HPDs disrupts spatial hearing as expected, specifically localization performance and monitoring of speech signals. There was a significant interaction between hemifield and signal-to-noise ratio (SNR), with speech intelligibility significantly affected when signals were presented from behind at reduced SNR. Results also suggest greater spatial hearing disruption using over-the-ear HPDs when compared to the removal of high frequency cues typically associated with NIHL through low-pass filtering. These results are consistent with reduced situational awareness as a self-reported barrier to routine HPD use, and was evidenced in our study by decreased ability to make accurate decisions about source location in a controlled dual-task localization experiment.

Subclinical Hearing Deficits in Noise-Exposed Firefighters

Noise-induced hearing loss (NIHL) is the most prevalent occupational disease in the world and firefighters are at increased risk of NIHL due to their frequent exposure to hazardous levels of noise during service. Adverse effects of NIHL include acceleration of age-related hearing loss and an increased risk of cognitive decline. A critical challenge in addressing NIHL is the delayed clinical presentation of symptoms and lack of sensitive tools for early detection. To study the early clinical symptoms of NIHL in this high-risk group, we collected hearing function data including behavioral audiometric thresholds and distortion product otoacoustic emissions (DPOAEs) in 176 firefighters during annual physical assessments. Results revealed significant deficits in cochlear outer hair cell function in the presence of normal audiograms. Additionally, 55% of firefighters self-reported changes in hearing, while 20% self-reported concerns about their balance. This study is the first to characterize DPOAEs in firefighters who display decreased DPOAE amplitudes with increasing years in the fire service. These effects were observed even when controlling for hearing loss and age and are suggestive of a link between hearing loss and occupational exposure to hazardous noise.

Application of Wireless Contralateral Routing of Signal Technology in Unilateral Cochlear Implant Users with Bilateral Profound Hearing Loss

The aim of the study was to determine if contralateral routing of signal (CROS) technology results in improved hearing outcomes in unilateral cochlear implant (CI) patients and provides similar gains in speech perception in noise to traditional monaural listeners (MLs).

The study is a prospective, within-subject repeated-measures experiment.

Adult, English-speaking patients with bilateral severe–profound sensorineural hearing loss using an Advanced Bionics CI (n = 12) in one ear were enrolled for the study.

Hearing performance in the monaural listening condition (CI only) was compared with the CROS-aided (unilateral CI + CROS) condition. Participants were tested for speech-in-noise performance using the Bamford-Kowal-Bench Speech-in-Noise™ test materials in the speech front/noise front (0 degrees/0 degrees azimuth), speech front/noise back (0 degrees/180 degrees azimuth), speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth), and speech monaural ear/noise deaf ear (90 degrees/270 degrees azimuth) configurations. Localization error was assessed using three custom stimuli consisting of 1/3 octave narrowband noises centered at 500 and 4000 Hz and a broadband speech stimulus. Localization stimuli were presented at random in the front hemifield by 19 speakers spatially separated by 10 degrees. Outcomes were compared with a previously described group of traditional MLs in the CROS-aided condition (normal hearing ear + CROS).

All participants were tested acutely with no adaptation to the CROS device. Statistical analyses were performed using Wilcoxon signed rank tests for nonparametric data and paired sample. Statistical significance was set to p < 0.00625 after Bonferroni adjustment for eight tests.

Significant benefit was observed from unaided to the CI + CROS–aided condition for listening in noise across most listening conditions with the greatest benefit observed in the speech deaf ear/noise monaural ear (90 degrees/270 degrees azimuth) condition (p < 0.0005). When compared with traditional MLs, no significant difference in decibel gain from the unaided to CROS-aided conditions was observed between participant groups. There was no improvement in localization ability in the CROS-aided condition for either participant group and no significant difference in performance between traditional MLs and unilateral CI listeners.

These findings support that unilateral CI users are capable of achieving similar gains in speech perception to that of traditional MLs with wireless CROS. These results indicate that the use of wireless CROS stimulation in unilateral CI recipients provides increased benefit and an additional rehabilitative option for this population when bilateral implantation is not possible. The results suggest that noninvasive CROS solutions can successfully rehabilitate certain monaural listening deficits, provide improved hearing outcomes, and expand the reach of treatment in this population.

Hearing with One Ear: Consequences and Treatments for Profound Unilateral Hearing Loss

There is an increasing global recognition of the negative impact of hearing loss, and its association to many chronic health conditions. The deficits and disabilities associated with profound unilateral hearing loss, however, continue to be under-recognized and lack public awareness. Profound unilateral hearing loss significantly impairs spatial hearing abilities, which is reliant on the complex interaction of monaural and binaural hearing cues. Unilaterally deafened listeners lose access to critical binaural hearing cues. Consequently, this leads to a reduced ability to understand speech in competing noise and to localize sounds. The functional deficits of profound unilateral hearing loss have a substantial impact on socialization, learning and work productivity. In recognition of this, rehabilitative solutions such as the rerouting of signal and hearing implants are on the rise. This review focuses on the latest insights into the deficits of profound unilateral hearing impairment, and current treatment approaches.

Self-Perceived Hearing Status Creates an Unrealized Barrier to Hearing Healthcare Utilization

OBJECTIVE

To examine sociodemographic and audiometric factors associated with hearing aid (HA) uptake in adults with hearing loss (HL), and to investigate the role of self-perceived hearing status on pursuit of hearing treatment. The relationship between self-perceived hearing status and HA adoption has not been reported in a nationally representative sample of United States (US) adults.

STUDY DESIGN

Cross-sectional analysis of nationwide household health survey.

METHODS

Audiometric and questionnaire data from the 2005 to 2012 National Health and Nutrition Examination Survey cycles were used to examine trends in untreated HL and HA adoption in US adults. Adjusted odds ratios for HA adoption were calculated for individuals with measured HL.

RESULTS

Of 5230 respondents, 26.1% had measurable HL, of which only 16.0% correctly self-identified their hearing status, and only 17.7% used an HA. Age, higher education, severe hearing impairments, and recent hearing evaluations, were positively associated with HA adoption.

CONCLUSION

Hearing loss is a global public health concern placing significant economic burden on both the individual and society. Self-reported hearing status is not a reliable indicator for HL, and measured HL is not correlated with increased rates of treatment. Recent hearing evaluation is positively associated with increased rates of treatment. Routine hearing assessment will help to better identify those with HL and improve access to hearing treatment.

LEVEL OF EVIDENCE

III Laryngoscope, 131:E289-E295, 2021.

Transcranial Attenuation in Patients with Single-Sided Deafness

Transcranial attenuation (TA) of bone-conducted sound has a high degree of variability by frequency and subject, which may play a role in the objective benefit of individuals with single-sided deafness (SSD) treated with a bone-anchored implant (BAI). This study sought to determine whether TA is predictive of benefit in individuals with SSD who receive a BAI. Adult, English-speaking patients with unilateral profound sensorineural hearing loss who underwent a BAI evaluation were included for study. Absolute TA values were consistent with previously published reports. Regression analysis indicated no correlation between TA values and aided speech-in-noise performance for any combined or individual frequencies. Measures of TA do not provide predictive value in determining behavioral outcomes in the SSD population. Specifically, low TA does not suggest improved outcomes with a BAI.

Ethnic disparity in skin complications following bone-anchored hearing aid implantation

OBJECTIVES

Sound processor loading after implantation of a bone-anchored hearing aid is often delayed by skin-site complications. This study examined the frequency of skin-site complications in various ethnic groups and determined factors that may lead to higher rates of skin-site complications resulting in delayed processor loading.

METHODS

Adult, English-speaking patients who underwent implantation of a bone-anchored hearing aid between 2007 and 2010 were reviewed. Demographic data including ethnicity, tobacco use, diabetes mellitus, immunosuppression, and long-term steroid use were determined. Major and minor skin-site complications and the time to processor loading were recorded.

RESULTS

The mean time to processor loading was 9.5 weeks, and the mean follow-up time was 23 months. There were no cases of osseointegration failure. African American patients had a significantly higher rate of major skin-site complications (p < 0.005) and a longer time to processor loading (mean, 17.6 weeks; p < 0.05) than the other ethnic groups. There was no significant difference in minor skin complication rates. There was no correlation between diabetes mellitus, long-term immunosuppression, or tobacco use and skin-site complications.

CONCLUSIONS

Skin complications can delay processor loading following implantation of a bone-anchored hearing aid. There is a higher rate of major skin-site complications in African American patients, and these often delay processor loading. The risk of skin-site complications is not correlated with smoking, diabetes mellitus, or immunosuppression. An increased risk of skin-site complications is an important consideration for preoperative counseling.

Bone-Anchored Implantation for Single-Sided Deafness in Patients with Less Than Profound Hearing Loss

Objective

The benefit of bone-anchored implantation (BAI) for the treatment of single-sided deafness (SSD) is well established. In this study, the authors sought to evaluate objective hearing outcomes and subjective benefits in patients undergoing BAI for SSD with residual hearing in the implanted ear.

Study Design

Case series with chart review.

Setting

Academic tertiary referral center.

Subjects and Methods

All adult, English-speaking patients undergoing BAI for SSD from 2004 to 2010 were included. Patients were divided into 2 groups: (1) residual hearing in the affected ear (≤90 db hearing level [HL] pure-tone average [PTA]) and (2) profound hearing loss in the affected ear (>90 dB HL PTA). Patients underwent pre- and postoperative objective hearing outcomes testing including speech-in-noise and monosyllabic word tests. Subjective outcomes were measured pre- and postoperatively using the Glasgow Hearing Aid Benefit Profile (GHABP).

Results

Patients in both groups showed significant improvement in all objective hearing measures following implantation ( P < .0001), and there were no significant differences in objective hearing outcomes between groups. Subjective benefits from BAI varied across patients according to GHABP results, but patients with residual hearing in the affected ear trended toward improved satisfaction with their device postoperatively.

Conclusion

Individuals with SSD and residual cochlear reserve can be successfully implanted with BAI, achieving significant improvements in objective hearing measures. Postoperative improvements do not seem to correlate with the preoperative audiometric testing scores. Although subjective benefit varies across patients, BAI is clearly a viable rehabilitation option for patients with SSD and less than profound hearing loss.

A clinical protocol for predicting outcomes with an implantable prosthetic device (Baha) in patients with single-sided deafness

BACKGROUND

The Baha implant is increasingly becoming a common form of treatment for individuals with single-sided deafness (SSD). However, evidence-based guidelines for determining candidacy in these patients are not yet established.

PURPOSE

The purpose of this study was to investigate the clinical utility of speech-in-noise testing as a part of the preoperative evaluation of the Baha device in patients with SSD.

RESEARCH DESIGN

The study design was a prospective cohort of 24 English-speaking adults comparing preoperative results on speech-in-noise measures using the Baha Cordelle II headband stimulator to postoperative results using the patient's external Baha processor.

INTERVENTION

Outcome measures included signal-to-noise ratio (SNR) loss as measured by the QuickSIN™ and scores of self-reported disability questionnaires.

RESULTS

Wilcoxon signed-rank test resulted in no significant difference between the preoperative and postoperative methods for measuring benefit on listening in noise tasks. Passing Bablok regression analysis showed the preoperative and postoperative results to be statistically equivalent, which suggests that postoperative results can be predicted during preoperative testing. Wilcoxon signed-rank test showed significant improvements in self-reported disability postoperatively.

CONCLUSIONS

The results support the use of speech-in-noise measures as an accurate predictor of overall benefit in patients with SSD prior to implantation.

Early Loading After Single-Stage Bone-Anchored Implantation in Adults

Objective. Classically, processor loading after single-stage bone-anchored implantation (BAI) surgery follows a 3-month osseointegration period. The purpose of this study was to examine audiometric outcomes and postoperative complications in adult patients undergoing single-stage BAI with processor loading at less than 6 weeks postoperatively.

Study Design. Retrospective review.

Setting. Otology clinic in a tertiary care academic center.

Subjects and Methods. A retrospective review was performed of all adult patients (>18 years) undergoing BAI from 2007 to 2010. Sixty-four patients met inclusion criteria. Fifty-five patients had unilateral hearing loss, including single-sided deafness, conductive hearing loss, or mixed hearing loss. Nine patients had bilateral hearing loss. Patients were divided into groups based on time to processor loading (>12 weeks, <12 weeks, <6 weeks). All patients were loaded with the external processor at less than 6 weeks when possible. Preoperative and postoperative audiometric evaluations were performed.

Results. There were no cases of osseointegration failure. All groups showed significant improvement in audiometric testing using their BAI ( P < .005), and there were no significant differences between patients loaded at less than 12 weeks and those loaded at less than 6 weeks ( P > .05). Major skin complications were seen in 9% of subjects and minor complications in 30%.

Conclusions. Single-stage BAI implantation with early processor loading is safe and effective in adults. All groups demonstrated significant audiometric benefit that was not affected in patients loaded early. Major and minor skin-site complications frequently delayed processor loading, but there were no cases of osseointegration failure in any group.