Continuous Noise Exposure Research Articles

Divergent effects of short-term and continuous anthropogenic noise exposure on Western Bluebird parental care behavior.

Sensory environments are rapidly changing due to increased human activity in urban and non-urban areas alike. For instance, natural and anthropogenic sounds can interfere with parent-offspring communication and mask cues reflective of predation risk, resulting in elevated vigilance at the cost of provisioning. Here we present data from two separate studies involving anthropogenic noise and nestling provisioning behavior in Western Bluebirds (Sialia mexicana): one in response to short-term (1 h) experimental noise playback and a second in the context of nests located along a gradient of exposure to continuous noise. In the short-term playback experiment, nests were sequentially exposed to trials with either traffic noise or a silent audio track. The effect of the playback type interacted with the effect of the order in which trials were presented. The outcome was that provisioning rates during second trials with the silent track playback were higher than provisioning rates during noise playback on first or second trials, but not first trials with the silent track playback. Additionally, failed provisioning attempts only occurred during noise trials. In contrast, provisioning rates increased with the amplitude of noise among nests located in a gradient of continuous noise exposure. For nests along the noise gradient, the latency to resume provisioning behavior following human disturbance from approaching the nest negatively covaried with noise exposure amplitude. Specifically, birds resumed provisioning behavior more quickly with increased noise amplitude. Collectively, both studies demonstrate that noise can influence avian parental care of offspring, but the direction of the effect of noise are opposite. This difference could reflect variation in populations, noise characteristics or latent environmental contexts, or different ages of nestlings. However, it is also possible that the divergent responses reflect important differences in organismal responses to short-term versus long-term noise exposure. The possibility of mismatches in responses to short-term versus long-term noise exposure should be the focus of additional research, especially because short-term noise exposure experiments are often used to understand the consequences of noise pollution for organisms living in noisy environments.

Anthropogenic noise disrupts early-life development in a fish with paternal care

Anthropogenic noise is a global pollutant but its potential impacts on early life-stages in fishes are largely unknown. Here, using controlled laboratory experiments, we tested for impacts of continuous or intermittent exposure to low-frequency broadband noise on early life-stages of the common goby (Pomatoschistus microps), a marine fish with exclusive paternal care. Neither continuous nor intermittent noise exposure had an effect on filial cannibalism, showing that males were capable and willing to care for their broods. However, broods reared in continuous noise covered a smaller area and contained fewer eggs than control broods. Moreover, although developmental rate was the same in all treatments, larvae reared by males in continuous noise had, on average, a smaller yolk sac at hatching than those reared in the intermittent noise and control treatments, while larvae body length did not differ. Thus, it appears that the increased consumption of the yolk sac reserve was not utilised for increased growth. This suggests that exposure to noise in early life-stages affects fitness-related traits of surviving offspring, given the crucial importance of the yolk sac reserve during the early life of pelagic larvae. More broadly, our findings highlight the wide-ranging impacts of anthropogenic noise on aquatic wildlife living in an increasingly noisy world.

Noise Causes Work Stress in Traditional Boat Workers

Introduction: Noise is an unwelcome sound that disrupts workers. Noise is present in every workplace, including ship engine noise. Continuous noise exposure can result in health issues, including hearing loss. Noise can cause stress on traditional boat workers because being continuously exposed to noise causes an uncomfortable feeling in the work environment. This uncomfortable feeling can trigger stress on ferry boat workers. This study aims to determine the relationship between noise and work stress on ferry boat workers at the Pier of Kampung Baru Tengah, Balikpapan. Methods: This study used a quantitative approach with a cross-sectional research design with 44 respondents. The instruments used a Sound Level Meter to measure Noise Level and Dass 21 Questionnaire with an interview method to measure Job Stress. Results: As many as 35 respondents were exposed to noise caused by traditional boat engines, and more than 50% of workers did not experience work stress (normal). The results of this study indicated a relationship between noise and work stress in traditional boat workers. Conclusion: The direction of the association between noise and work stress was positive but low, meaning that, as noise levels rise, so does the risk of workplace stress.

Raise your pitch! Changes in the acoustic emissions of resident bottlenose dolphins in the proximity of vessels

AbstractMaritime traffic is a major contributor of anthropogenic disturbance for cetaceans, especially for coastal populations, such as that of resident common bottlenose dolphins (Tursiops truncatus) in the Sado estuary (Portugal). Animals have been found to adjust their vocal behavior by changing vocal rates, or call frequency and/or duration, to overcome masking effects of underwater noise. To evaluate the potential impacts of boat traffic on the acoustic behavior of these dolphins, emission rates and acoustic characteristics of whistles and burst‐pulsed signals were analyzed with and without boats operating nearby. In this study, no significant differences were found for emission rates of each type of vocal element in the presence of vessels. However, significant differences were found in acoustic parameters, namely changes in frequency and duration, for whistles and for pulsed sounds (creaks, grunts, squeaks, and gulps). These changes, such as a shift in vocal frequencies and production of shorter signals, may represent behavioral strategies to compensate for the noisy environment. Although resident bottlenose dolphins in the Sado region seem to have developed some tolerance to vessel noise, continuous noise exposure and noise‐induced frequency shifts in vocal outputs could have indirect fitness costs for this population.

Effects of aircraft noise cessation on blood pressure, cardio- and cerebrovascular endothelial function, oxidative stress, and inflammation in an experimental animal model

Large epidemiological studies have shown that traffic noise promotes the development of cardiometabolic diseases. It remains to be established how long these adverse effects of noise may persist in response to a noise-off period. We investigated the effects of acute aircraft noise exposure (mean sound level of 72 dB(A) applied for 4d) on oxidative stress and inflammation mediating vascular dysfunction and increased blood pressure in male C57BL/6 J mice. 1, 2 or 4d of noise cessation after a 4d continuous noise exposure period completely normalized noise-induced endothelial dysfunction of the aorta (measured by acetylcholine-dependent relaxation) already after a 1d noise pause. Vascular oxidative stress and the increased blood pressure were partially corrected, while markers of inflammation (VCAM-1, IL-6 and leukocyte oxidative burst) showed a normalization within 4d of noise cessation. In contrast, endothelial dysfunction, oxidative stress, and inflammation of the cerebral microvessels of noise-exposed mice did not improve at all. These data demonstrate that the recovery from noise-induced damage is more complex than expected demonstrating a complete restoration of large conductance vessel function but persistent endothelial dysfunction of the microcirculation. These findings also imply that longer noise pauses are required to completely reverse noise-induced vascular dysfunction including the resistance vessels.

Auditory Deficits in Employees of Business Process Outsourcing (BPO): Need to Take Preventative Action.

The present study aimed to explore auditory deficits in full-time call center workers. A total of sixty participants participated, which was divided into two groups, viz. experimental group and control group. The complete audiological test battery was performed. On comparing the groups, significant differences were obtained for both ears while analyzing the TEOAEs, PTA1, and PTA2 (high-frequency audiometry). From the results, it can be delineated that BPO employees are at risk for sensorineural hearing loss following continuous noise exposure. We conclude that this type of hearing loss may be considered an iceberg, and to overcome all the issues related to noise exposure, all BPO employees should undergo periodic audiological, psychological, and health screening.

Noise Exposure and Hearing Loss among Workers at a Hammer Forge Company.

The National Institute for Occupational Safety and Health (NIOSH) evaluated continuous and impact noise exposures and hearing loss among workers at a hammer forge company. Full-shift personal noise exposure measurements were collected on forge workers across 15 different job titles; impact noise characteristics and one-third octave band noise levels were assessed at the forge hammers; and 4,750 historic audiometric test records for 483 workers were evaluated for hearing loss trends. Nearly all workers' noise exposures exceeded regulatory and/or recommended exposure limits. Workers working in jobs at or near the hammers had full-shift time-weighted average noise exposures above 100 decibels, A-weighted. Impact noise at the hammers reached up to 148 decibels. Analysis of audiometric test records showed that 82% of workers had experienced a significant threshold shift, as defined by NIOSH, and 63% had experienced a standard threshold shift, as defined by the Occupational Safety and Health Administration (OSHA). All workers with an OSHA standard threshold shift had a preceding NIOSH significant threshold shift which occurred, on average, about 7 years prior. This evaluation highlights forge workers' exposures to high levels of noise, including impact noise, and how their hearing worsened with age and length of employment.

The noise profile and hearing impact of commercial fiberglass reinforced plastic speed boats in Port Blair, Andaman and Nicobar Islands

Background: Hearing impairment may result from tourism-related vehicle engine noise in Port Blair, Andaman, and Nicobar Islands. Aims and Objectives: Measure noise levels and test commercial fiberglass-reinforced plastic (FRP) speedboat operators for hearing loss. Materials and Methods: Hearing loss and noise impacts were checked in a total of 145 male crew members and workers exposed to commercial FRP-speedboat outboard engine noise. 18–50-year-olds with 1–20 years of experience participated. To detect hearing loss, noise-induced hearing loss (NIHL) risk indicators that could appear as a 4 kHz noise notch and the existence of high-frequency sloping hearing loss were detected using pure tone audiometry. The level of noise exposure was measured in conjunction with a questionnaire to assess an individual’s general knowledge of the effects of noise and hearing loss. Results: A 4 kHz noise notch, some high-frequency slope hearing loss, and an overall hearing loss rate of 42.1% were found in 145 participants. Out of these, 15.9% had the most common bilateral notch. Bilateral high-frequency sloping was 10.3%, Unilateral high-frequency sloping was 4.9%, and unilateral 4 kHz notch was 11.0%. According to the questionnaire, research participants are shockingly unaware of noise-induced hearing loss. The FRP Speedboat outboard engine’s measured noise level ranged from 79.7 to 89.4 dB (A). Conclusion: The FRP Speedboat crews were at risk of hearing loss, specifically NIHL with continuous noise exposure. High frequency sloping hearing loss, mild to moderate hearing loss, and a substantial 4 kHz noise notch are found in noise-exposed employees. Awareness is needed to prevent irreversible hearing loss.

INFLUENCE OF INDIVIDUAL CHARACTERISTICS, BEHAVIOR AND NOISE INTENSITY ON BLOOD PRESSURE IN PONOROGO PLASTIC INDUSTRY’S WORKERS

Background: Noise is an unwanted sound that can be caused by any human activity. Continuous use of machines that produce noise in the work environment will have a negative impact on workers, for example is increasing blood pressure. Purpose: This study aimed to analyze the influence of individual characteristics, behavior and noise intensity on increasing blood pressure in workers in the Ponorogo’s plastic industry. Methods: The study used prospective cohort design. The sample of the study was 32 respondents who received continuous noise exposure from injection machine for 8 hours/ day. The variables include individual characteristics, behavior, noise intensity, and increased blood pressure. The data were analyzed using SPSS with paired sample t-test and multiple linear regression. Results: The result showed that the average increase in systolic and diastolic blood pressure before and after working is 5.75 mmHg and 5.31 mmHg. If analyzed by statistical paired t-test, the significance value of p = 0.00 < α = 0.05 is obtained. Furthermore, multiple linear regression test is used for variables of individual characteristics, behavior and noise intensity on increasing blood pressure showing a significance value of 0.00 <0.05 and F count (6.79 and 6.32) > F table (2.49). Conclusion: Individual characteristics, behavior and noise intensity have an effect on increasing blood pressure in workers in the Ponorogo’s plastic industry. Medical checkup and ear protection equipment are needed for workers.

Effects of Noise Hazards towards Physiology Especially Heart Rate Performance among Worker in Manufacturing Industry and Their Prevention Strategies: A Systematic Review.

Background:Occupational noise exposure is one of the environmental factors that pose safety and health risks among workers in factories. This systematic review focuses on the activities that cause noise hazards toward workers’ heart rate, other physiological conditions, and strategies to prevent noise exposure in the manufacturing industry.Methods:Through a comprehensive literature review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the Cochrane method were used. The appraisal of quality was conducted by using the Critical Appraisal Skills Programme (CASP) to fulfil the selected keywords.Results:Occupational noise exposure not only affects the workers’ most common issues, such as heart rate, but also other physiological factors, such as blood pressure. The outcome showed that different level of continuous noise exposure with high intensity decibels affects the heart rate of the workers. Source, path, receiver was recommended strategies for basic noise prevention in engineering control.Conclusion:Therefore, noise give significant effects towards human workers in related industry. Study related to noise effects towards heart rate performance led to future prevention and innovation.

Pure Tone Audiometry Evaluation Method Effectiveness in Detecting Hearing Changes Due to Workplace Ototoxicant, Continuous Noise, and Impulse Noise Exposures.

The purpose of this retrospective cohort study was to compare the relative risks (RR) of hearing impairment due to co-exposure of continuous noise, impulse noise, metal ototoxicants, and organic solvent ototoxicants using several pure tone audiometry (PTA) evaluation methods. Noise and ototoxicant exposure and PTA records were extracted from a DoD longitudinal repository and were analyzed for U.S. Air Force personnel (n = 2372) at a depot-level aircraft maintenance activity at Tinker Air Force Base, Oklahoma using an historical cohort study design. Eight similar exposure groups based on combinations of ototoxicant and noise exposure were created: (1) Continuous noise (reference group); (2) Continuous noise + Impulse noise; (3) Metal exposure + Continuous noise; (4) Metal exposure + Continuous noise + Impulse noise; (5) Solvent exposure + Continuous noise; (6) Solvent exposure + Continuous noise + Impulse noise; (7) Metal exposure + Solvent exposure + Continuous noise; and (8) Metal exposure + Solvent exposure + Continuous noise + Impulse noise. RR of hearing impairment compared to the Continuous noise-exposed reference group was assessed with five PTA evaluation methods including (1) U.S. Department of Defense (DoD) Significant Threshold Shift (STS), (2) Occupational Safety and Health Administration (OSHA) age-adjusted STS, (3) National Institute for Occupational Safety and Health (NIOSH) STS, (4) NIOSH Material Hearing Impairment, and (5) All Frequency Threshold Average. Hearing impairment was significantly worse for SEG (2) combined exposure to continuous noise and impulse noise only for the PTA evaluation method (2) OSHA Age Adjusted with an RR of 3.11, [95% confidence interval (CI), 1.16-8.31] and was nearly significantly different using PTA evaluation method (4) NIOSH Material Hearing Impairment with an RR of 3.16 (95% CI, 0.99-10.15). Despite no significant differences for SEGs with an ototoxicant exposure, PTA evaluation method (3) NIOSH STS was most sensitive in detecting hearing changes for SEG (8) Metal exposure + Solvent exposure + Continuous noise + Impulse noise as demonstrated by a RR of 1.12 (95% CI, 0.99-1.27). Results suggest that a single PTA evaluation technique may not be adequate in fully revealing hearing impairment risk due to all stressors and tailoring the PTA evaluation technique to the hazards present in the workplace could better detect hearing impairment. Additionally, results suggest that PTA may not be effective as the sole technique for evaluating hearing impairment due to ototoxicant exposure with continuous noise co-exposure.

Impulse Noise Induced Hidden Hearing Loss, Hair Cell Ciliary Changes and Oxidative Stress in Mice.

Recent studies demonstrated that reversible continuous noise exposure may induce a temporary threshold shift (TTS) with a permanent degeneration of auditory nerve fibers, although hair cells remain intact. To probe the impact of TTS-inducing impulse noise exposure on hearing, CBA/J Mice were exposed to noise impulses with peak pressures of 145 dB SPL. We found that 30 min after exposure, the noise caused a mean elevation of ABR thresholds of ~30 dB and a reduction in DPOAE amplitude. Four weeks later, ABR thresholds and DPOAE amplitude were back to normal in the higher frequency region (8–32 kHz). At lower frequencies, a small degree of PTS remained. Morphological evaluations revealed a disturbance of the stereociliary bundle of outer hair cells, mainly located in the apical regions. On the other hand, the reduced suprathreshold ABR amplitudes remained until 4 weeks later. A loss of synapse numbers was observed 24 h after exposure, with full recovery two weeks later. Transmission electron microscopy revealed morphological changes at the ribbon synapses by two weeks post exposure. In addition, increased levels of oxidative stress were observed immediately after exposure, and maintained for a further 2 weeks. These results clarify the pathology underlying impulse noise-induced sensory dysfunction, and suggest possible links between impulse-noise injury, cochlear cell morphology, metabolic changes, and hidden hearing loss.

Survey on present status of noise exposure of workers in metal processing industry

Objective: To investigate the distribution of noise exposure between non-steady state noise and steady-state noise for metal processing workers, which will provide scientific basis for the prevention and treatment of noise hazards in metal processing industry. Methods: The cross-section method was used to investigate the noise exposure of 737 workers from three metal processing industries in Zhejiang Province from October to December 2017. The general demographic information and occupational history were collected by questionnaire. The noise was recorded by individual noise meters, and the noise exposure intensity (equivalent continuous A-weighted noise exposure level normalized to an 8 h-working-day, L(Aeq, 8 h)) and kurtosis were calculated. Results: Workers exposed to noise in the metal processing industry were mainly 18-40 years old (527 workers, 71.51%) , men (570 workers, 77.34%) , and junior high school education background (416 workers, 56.45%) . There were 572 workers (77.61%) with noise exposure intensity (L(Aeq, 8 h)) greater than 85 dB (A) , 558 workers (75.71%) exposed to non-steady state noise (kurtosis ≥4) , and 634 workers (86.02%) with exposure duration less than 8 years. Among the 30 work types investigated, the work types with noise intensity reaching 100% were the stamping, welding and others from a children's car manufacturing factory in Ningbo, operating, chamfering, tapping, and thread rolling from an automobile parts manufacturing factory in Ningbo; The work types with a rate of 100% exposed to non-steady state noise were the grinding from a children's car manufacturing factory in Ningbo, assembling, assembly operating and others from an automobile brake manufacturing factory in Wenzhou, and polishing from an automobile parts manufacturing factory in Ningbo. Conclusion: Metal processing workers have a high rate of over-standard exposed to high noise intensity and a high proportion exposed to non-steady state noise. It is necessary to take sound insulation and noise reduction engineering control, and strengthen personal protection and occupational health management measures to prevent and control the noise hazards.

Cochlear hair cells of echolocating bats are immune to intense noise

Exposure to intense noise can damage cochlear hair cells, leading to hearing loss in mammals. To avoid this constraint, most mammals have evolved in relatively quiet environments. Echolocating bats, however, are naturally exposed to continuous intense sounds from their own and neighboring sonar emissions for maintaining sonar directionality and range. Here, we propose the presence of intense noise resistance in cochlear hair cells of echolocating bats against noise-induced hearing loss (NIHL). To test this hypothesis, we performed noise exposure experiments for laboratory mice, one nonecholocating bat species, and five echolocating bat species. Contrary to nonecholocating fruit bats and mice, the hearing and the cochlear hair cells of echolocating bats remained unimpaired after continuous intense noise exposure. The comparative analyses of cochleae transcriptomic data showed that several genes protecting cochlear hair cells from intense sounds were overexpressed in echolocating bats. Particularly, the experimental examinations revealed that ISL1 overexpression significantly improved the survival of cochlear hair cells. Our findings support the existence of protective effects in cochlear hair cells of echolocating bats against intense noises, which provides new insight into understanding the relationship between cochlear hair cells and intense noises, and preventing or ameliorating NIHL in mammals.

Development and Initial Validation of the Lifetime Exposure to Noise and Solvents Questionnaire in U.S. Service Members and Veterans.

Purpose A need exists to investigate the short- and long-term impact of noise exposures during and following military service on auditory health. Currently available questionnaires are limited in their ability to meet this need because of (a) inability to evaluate noise exposures beyond a limited time frame, (b) lack of consensus on scoring, (c) inability to assess impulse exposures (e.g., firearm use), (d) lack of a single questionnaire that assesses both military and nonmilitary exposures, and (e) lack of validity and reliability data. To address these limitations, the Lifetime Exposure to Noise and Solvents Questionnaire (LENS-Q) was developed. The purpose of this report is to describe the development and initial validation of the LENS-Q as a measure of self-reported noise exposure. Method Six hundred ninety participants, consisting of current Service members and recently military-separated (within about 2.5 years) Veterans, completed the LENS-Q, additional study questionnaires, and comprehensive audiometric testing. Noise exposure scores were computed from LENS-Q responses using a simple scoring algorithm that distinguishes between different cumulative levels of exposure and allows for the inclusion of both continuous and impulse noise exposures. Results The LENS-Q demonstrates good construct validity as evidenced by measures of hearing loss, tinnitus, and subjective hearing difficulties all increasing with an increase in noise exposure scores. A logistic regression, adjusting for age and sex, revealed that participants in the highest exposure group were 2.4-3.9 times more likely to experience hearing loss, 2.7-2.8 times more likely to experience tinnitus, and 3.0-3.7 times more likely to report hearing difficulties compared with individuals in the lowest exposure group. Conclusions The LENS-Q captures noise exposure over an individual's lifetime and provides an alternative scoring metric capable of representing exposure to both continuous and impulse noise. Findings suggest that the LENS-Q is a valuable tool for capturing and measuring both military and nonmilitary noise exposure. Supplemental Material https://doi.org/10.23641/asha.14582937.

Ambient noise exposure induces long-term adaptations in adult brainstem neurons

To counterbalance long-term environmental changes, neuronal circuits adapt the processing of sensory information. In the auditory system, ongoing background noise drives long-lasting adaptive mechanism in binaural coincidence detector neurons in the superior olive. However, the compensatory cellular mechanisms of the binaural neurons in the medial superior olive (MSO) to long-term background changes are unexplored. Here we investigated the cellular properties of MSO neurons during long-lasting adaptations induced by moderate omnidirectional noise exposure. After noise exposure, the input resistance of MSO neurons of mature Mongolian gerbils was reduced, likely due to an upregulation of hyperpolarisation-activated cation and low voltage-activated potassium currents. Functionally, the long-lasting adaptations increased the action potential current threshold and facilitated high frequency output generation. Noise exposure accelerated the occurrence of spontaneous postsynaptic currents. Together, our data suggest that cellular adaptations in coincidence detector neurons of the MSO to continuous noise exposure likely increase the sensitivity to differences in sound pressure levels.

Effects of hearing protector devices on speech intelligibility: the importance of individualized assessment

Objectives. This study aimed to compare speech intelligibility in noise with and without hearing protection devices (HPDs). Methods. Fifty-one workers were distributed into three groups: noise-induced hearing loss group (NIHLG), normally hearing noise-exposed group (NG) and normally hearing non-exposed to noise group (CG). A free field system was used to emit monosyllables (65, 70 and 75 dB) and pink noise in different signal-to-noise ratios (SNRs) (0, −5, −10 and −15). Results. In situations with HPDs, all groups showed a decrease in the percentage of correct responses with an increase in noise level. The HPD had little effect on speech intelligibility in the NIHLG and NG. Considering the effect caused by the HPD on speech intelligibility, it was observed that the group with the greatest loss was the CG for SNRs of −5, −10 and −15. Conclusion. Although speech intelligibility is influenced by the hearing threshold, the noise level and SNR are crucial for good speech intelligibility, either with or without an HPD. It is highlighted that the NG had worse results when compared with the CG, which may indicate changes in the auditory pathway resulting from continuous noise exposure, even in the absence of changes in the audiometric thresholds.

Impact Assessment of Workers on Short Term Exposure within the Recommended Permissible Noise Exposure Limit (85 - 90 dBA)

As occupational safety and health become a focus in developing third world countries like the Philippines, research, test, and measurement were given investment to improve the status of health and safety. This study sought to determine the effect of 85 to 90 dBA exposure to workers in a controlled environment. Age, work experience, and gender were also assessed for possible correlation on the performance while exposed to different noise levels. One at a time, workers proceed to the audio isolation booth with observation window, controlled temperature, relative humidity, lightings, and noise level to complete three tasks namely abstract and logic test for 60 minutes, simplified mathematics test for 30 minutes, and set-up activity for 15 minutes. Each worker has to complete six sets of tests with a different continuous noise exposure level of 85 to 90 dBA. Observations of incidents inside the booth were also noted in the results. Workers perform best with a mean of 72% for 85 dBA in declining pattern to 38% performance for 90 dBA noise exposure for the Abstract and logic test. The same pattern was observed for a simplified mathematics test with the mean of 86.80% for 85 dB dropping to 64% for 90 dBA exposure while the actual set-up activity obtained 65% mean for worker completion when exposed to 85 dBA sliding to 35% for 90 dBA. In addition, the tallied health and safety issues raised by the workers and notes by the observers resulted in an increasing trend from 5% for 85 dBA, 11% for 86 to 88 dBA, 26% for 89 dBA, and 37% for 90 dBA. On the other hand, Pearson correlation confirms the negative correlation of noise level to abstract and logic, simple mathematics, and practical assembly set-up while noise level has a positive correlation with Health and Safety issues. Overall, if the 90 dBA noise level or higher is maintained in a specific workplace without any controls or interventions to lower down the noise level, the productivity and efficiency of workers will be low while their health and safety might be at risk.

Elliott Berger's contributions to military hearing conservation and standards

Military organizations world-wide experience the great majority of the extreme occupational noise exposures. The noise sources range from tanks and armored personnel carriers to fighter jets and shoulder launched missiles. It is a difficult task to protect the men and women who serve their countries and experience these extreme environments where the continuous noise levels can reach 150 dBA and the peak noise levels from firing weapons can reach 195 dBpeak. Stable methods to measure hearing protector attenuation benefit the development and optimization of hearing protection. National and international standards measuring hearing protection attenuation have been the focus of much of Elliott's work during his career and now in semi-retirement. These standards have been the catalysts that have enabled the development of improved hearing protectors that help conserve the hearing of service members in military noise environments. Data will be presented showing ranges of military continuous and impulsive noise exposures, the amount of hearing protection attenuation needed to meet US DoD noise exposure criteria, and the ANSI standards for the measurement of hearing protector attenuation.

Are Brighter Days Ahead? Light and Sound in the Pediatric Intensive Care Unit

PURPOSE. Though intended to heal, Pediatric Intensive Care Unit (PICU) environments are often a source of stress for patients and families. Disturbances in patient sleep quantity and quality are thought to be due to loss of the day/night cycle and continuous light and noise exposure. Environmental disruptions may exacerbate delirium, which is associated with increased ventilator days and mortality in children. ICU sound levels frequently exceed World Health Organization (WHO) recommendations; there are no similar standards for hospital light. Little PICU-specific data exists. The purpose of this study was to describe light and …