The Association Between Occupational Exposure to Hand-Arm Vibration and Hearing Loss: A Systematic Literature Review

Effect of concurrent exposure to noise and hand-transmitted vibration on auditory and cognitive attention under simulated work with construction tools

Objectives. This study aimed to investigate the effects of separate and concurrent exposure to occupational noise and hand-transmitted vibration (HTV) on auditory and cognitive attention. Methods. The experimental study was conducted with 40 construction workers who were exposed to noise (A-weighted equivalent sound pressure level of 90 dB) and to HTV (10 m/s2 at 31.5 Hz), and concurrent exposure to both for 30 min under simulated work with vibrating equipment used in construction. Cognitive performance aspects were then evaluated from each individual in two pre-exposure and post-exposure settings for each session. Results. The effect sizes of concurrent exposure (HTV + noise) and separate exposure to noise on auditory attention were very close (effect size = 0.648 and 0.626). The largest changes in the difference of response time in both types of attention (selective and divided attention) were related to the concurrent exposure scenario and then exposure to HTV, respectively. The highest effects for the correct response of selective and divided attention are related to concurrent exposure (HTV + noise) and then noise exposure, respectively. Conclusion. The HTV effect during concurrent exposure is hidden in auditory attention, and noise has the main effects. The divided attention was more affected than the selective attention in the different scenarios.

Hearing Loss in Space Flights: A Review of Noise Regulations and Previous Outcomes

Noise is the primary cause of hearing loss during space flight. Throughout every phase of flight, particularly during launch, a significant amount of noise is generated and transferred via the vehicle's structure to the places inhabited by the crew. The results of the previous studies provide insights into space flights that may have significant effects on hearing loss. Certain precautions must be taken to ensure the habitability of the spacecraft and prevent potential hearing loss in astronauts or space flight participants.

Effect of noise and hand-transmitted vibration exposure on hearing and equilibrium under a simulated work environment with building tools

BACKGROUND

Construction workers are exposed to hand-transmitted vibration (HTV) and/or noise caused by vibrating hand tools in the work environment.

OBJECTIVE

The present study aims to investigate the effects of exposure to HTV and/or noise on workers' hearing loss and body balance.

METHODS

Forty construction workers were exposed to HTV (10 m/s2 rms, 31.5 Hz) and/or typical construction noise (90 dBA) in three simulated experiment scenarios with the vibrating hand-held tool for 30 minutes over three days. The hearing loss from 1000 to 6000 Hz and the body balance were determined before and after each exposure scenario.

RESULTS

Separate noise exposure at all frequencies except for 1000 Hz could significantly affect hearing threshold levels (p-value<0.05). Separate exposure to HTV cannot lead to a remarkable effect on hearing loss (p-value>0.05); however, it can synergistically increase the effect of noise on hearing loss. Also, the affected frequency range in concurrent exposure has been greater than in separate noise exposure. The separate effects of exposure to HTV and noise on the subjects' body balance were not statistically significant (p-value>0.05); however, these effects became significant in concurrent exposure (p-value<0.05). Based on the estimated effect sizes, noise could synergistically increase the observed effect of HTV on body balance.

CONCLUSION

There is a synergistic interaction between HTV and noise on hearing loss and body balance. It seems necessary to pay attention to the risk evaluation of simultaneous exposure to noise and HTV when setting the occupational action limit values.

The Associations Between Workplace Noise, Ototoxic Chemicals, and Tinnitus

OBJECTIVE

To investigate the occupational risk factors associated with tinnitus in the Australian working population.

DESIGN

The research was conducted using data collected from the Australian Workplace Exposure Survey-Hearing, a national cross-sectional study of 4970 workers conducted in 2016 to 2017. Workers were asked if they experienced tinnitus and if they answered affirmatively, they were asked about the frequency and length of the presentations. Based on their answers, each worker was categorized as having no tinnitus or any tinnitus, with an additional group of workers with any tinnitus subcategorized as having constant tinnitus. Exposure assessment was conducted using an automated expert assessment method. Exposures included daily noise (L Aeq,8h ), hand-arm vibration (A(8)), impulse noise, smoking status, styrene, trichloroethylene, toluene, n-hexane, p-xylene, ethylbenzene, lead, and carbon monoxide. Univariate and multivariate logistic regression models were used to examine the associations between workplace exposures and tinnitus.

RESULTS

Workers with an estimated noise exposure above the workplace limit (L Aeq,8h > 85 dBA) had 1.73 (95% confidence interval [CI]: 1.42 to 2.11) increased odds of any tinnitus and 2.15 (95% CI: 1.60 to 2.89) odds of constant tinnitus. The odds of workers having any tinnitus increased with increasing noise exposure levels in a dose-response relationship that strengthened when considering only those with constant tinnitus. In the fully adjusted model, statistically significant associations were seen for lead exposure with both any and constant tinnitus, toluene exposure with constant tinnitus, and carbon monoxide exposure with any tinnitus.

CONCLUSIONS

These results suggest that, in addition to workplace noise, occupational exposures to lead, toluene, and carbon monoxide are associated with tinnitus.

Occupation and 20-year hearing decline: findings from The HUNT Study

BACKGROUND

Studies show that certain occupations are associated with an increased risk of hearing loss. However, many studies are cross-sectional, and the few longitudinal studies are mostly small or focus on only one occupation.

AIMS

We aimed to quantify the long-term hearing decline among workers in different occupations and assess whether the change differs between the occupations.

METHODS

The study population was 4525 adults who participated in two population-based health studies in Norway, HUNT2 1996-1998 and HUNT4 2017-2019. Linear regression models assessed the association between occupations (clerks as reference) and 20-year hearing decline (hearing thresholds at 3-6 kHz, averaged over both ears) from HUNT2 to HUNT4. Models were adjusted for age, sex, recurrent ear infections, smoking and ear pathology.

RESULTS

Among the participants (40% men), the mean age at HUNT2 was 31.2 ± 5.4 years (range 20-39) and the average 20-year hearing decline was 11.3 ± 9.8 dB. Occupations that were associated with larger hearing decline included other craft and related trades workers (3.9 dB, 95% confidence interval [CI] 0.2-7.7) and building frame and related trades workers (3.4 dB, 95% CI 1.3-5.4). Among occupations with larger hearing decline, a higher proportion of the workers reported exposure to noise.

CONCLUSIONS

This large longitudinal study shows a larger long-term hearing decline among building frame workers and craft and related trades workers. Differences between occupations were modest, which may indicate successful preventive measures in Norway during the last two decades.

Proposal of Combined Noise and Hand-Arm Vibration Index for Occupational Exposure: Application to a Study Case in the Olive Sector

In many production and industrial sectors, workers are exposed to noise and hand-arm vibrations (HAV). European directives have established the maximum limit values or exposure action values for noise and vibration independently. However, in many cases, workers who endure hand-arm vibration also receive high noise levels. This research suggests a procedure to aid the establishment of precautionary measures for workers with simultaneous exposure to both physical agents. This procedure defines a combined index based on the energy doses for both noise and HAV. From this combined index, the suggested methodology allows a recommended exposure time for workers with simultaneous noise and HAV exposure to be calculated. This methodology can be adapted to tackle the relative importance assigned to both agents according to the safety manager and new knowledge on combined health effects. To test this method, a measurement campaign under real working conditions was conducted with workers from the olive fruit-harvesting sector, where a variety of hand-held machinery is used. The results of the study case show that the suggested procedure can obtain reliable exposure time recommendations for simultaneous noise and HAV exposures and is therefore a useful tool for establishing prevention measures.

Coexposure to Solvents and Noise as a Risk Factor for Hearing Loss in Agricultural Workers

OBJECTIVE

This study addressed the relationship of hearing loss and coexposure to solvents and noise among farmers and ranchers in central United States.

METHODS

The surveillance study included surveys to stratified random samples of operations in 2018 and 2020 (n = 34,146), requesting information on injuries, illnesses, exposures, and preventive measures. Responses (n = 7495) were analyzed using hierarchical multinomial logistic regression, adjusting for personal and work characteristics.

RESULTS

Nearly 60% of respondents exposed to both solvents and noise reported hearing loss. The exposures increased the adjusted odds of moderate/severe hearing loss as follows: solvents alone, (odds ratio [OR], 1.49; 95% confidence interval [CI], 0.93-2.38), noise alone (OR, 4.42; 95% CI, 3.39-5.76), and coexposure to both noise and solvents (OR, 6.03; 95% CI, 4.67-7.78).

CONCLUSIONS

Solvent exposure, along with noise, should be considered in hearing conservation programs among farmers and ranchers.

[Triggers and predictors of development and formation of sensorineural hearing loss]

The purpose of the study is to review the results of scientific researches in recent years in an expanded interdisciplinary view of the problem of etiopathogenesis of sensorineural hearing loss, as well as the role of comorbidities and triggers in the formation of persistent changes in the audio-receiving part of the auditory analyzer.

Noise Induced Hearing Loss and Tinnitus-New Research Developments and Remaining Gaps in Disease Assessment, Treatment, and Prevention

Long-term noise exposure often results in noise induced hearing loss (NIHL). Tinnitus, the generation of phantom sounds, can also result from noise exposure, although understanding of its underlying mechanisms are limited. Recent studies, however, are shedding light on the neural processes involved in NIHL and tinnitus, leading to potential new and innovative treatments. This review focuses on the assessment of NIHL, available treatments, and development of new pharmacologic and non-pharmacologic treatments based on recent studies of central auditory plasticity and adaptive changes in hearing. We discuss the mechanisms and maladaptive plasticity of NIHL, neuronal aspects of tinnitus triggers, and mechanisms such as tinnitus-associated neural changes at the cochlear nucleus underlying the generation of tinnitus after noise-induced deafferentation. We include observations from recent studies, including our own studies on associated risks and emerging treatments for tinnitus. Increasing knowledge of neural plasticity and adaptive changes in the central auditory system suggest that NIHL is preventable and transient abnormalities may be reversable, although ongoing research in assessment and early detection of hearing difficulties is still urgently needed. Since no treatment can yet reverse noise-related damage completely, preventative strategies and increased awareness of hearing health are essential.