'Cultural Insights into Adults' Hearing Awareness and Personal Listening Device Habits: A Survey Study.

Objective: The aim of this study was to investigate adults' habits regarding personal listening devices (PLDs), associated factors such as tinnitus and hearing threshold shift, and their knowledge of safety measures, including the use of hearing protectors in noisy environments. Design: A cross-sectional survey was designed and distributed online. Study Sample: Participants between the ages of 18 and 40 years were invited to complete the survey. The online survey was filled out by 274 individuals with an average age of 24.2 years (SD= 5.1 years). Based on age, the participants were grouped into young adults (18-23 years old, 151 participants) and adults (24-40 years old, 123 participants). The estimation of noise exposure was calculated based on self-reported responses of PLD use. Two categories emerged from this calculation: the participants with exposure lower than 80 dB were in the low exposure category (N: 196, 62.9 dB), while the participants with exposure higher than 80 dB were in the high exposure category (N: 78, 89.9 dB). Results: Based on the age categories, most of the questionnaire answers were similar between the young adults and the adults, revealing similar habits in using their PLDs. However, the investigation based on exposure revealed differences, as the participants with high exposure levels were more likely to have hobbies that involved noise, and they were less likely to obtain hearing evaluations. Among the participants, 30% used their devices at the maximum volume level and on a daily basis. 33.5% reported experiencing worsening in hearing, 2.4% reported persistent tinnitus, 94.1% knew that hearing protectors were available but only 20.7% reported using hearing protectors. Conclusion: The study concludes that adults are at risk of hearing loss due to unsafe listening habits. A discrepancy between knowledge and practice is apparent and needs to be addressed in young adults by increasing awareness of hearing loss, hearing protection and annual hearing evaluation.

The protective effectiveness of hearing protectors for noise-exposed workers and its influencing factors / 中国职业医学

ObjectiveTo explore the protective effect of hearing protectors worn by noise-exposed workers and its influencing factors. Methods A total of 329 occupational noise-exposed workers were selected as the research subjects by judgment sampling method. A questionnaire survey on the use of ear protectors and individual suitability tests was conducted. Intervention was carried out for those whose personal attenuation rating (PAR) did not pass the baseline standard. Results The median (M) and the 25th and 75th percentiles of baseline PAR were 17.0 (5.0, 22.5) dB. The baseline PAR of the workers who were male, aged 25-<35 years, with a working experience of 5-<15 years, with a college degree or above, wearing ear protectors for 5-<15 years, knowing the right way to wear ear protectors, and workers who wore ear protectors correctly during work was relatively high (all P<0.01). The unqualified rate of baseline PAR of the study subjects was 32.8%. The unqualified rate of baseline PAR of workers in automobile manufacturing enterprises was lower than that of workers in plastic enterprises and textile enterprises (9.2% vs 43.6%, and 9.2% vs 50.0%, both P<0.01). The M of the 108 unqualified worker on baseline PAR was improved after intervention (22.0 vs 1.0 dB, P<0.01). The rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly for the research subjects were 88.1%, 84.8%, and 86.6%, respectively. Workers in automobile manufacturing enterprises and plastic enterprises had higher rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly than those in textile enterprises (all P<0.01). Conclusion Gender, age, working experience, education level, duration of wearing ear protectors, knowledge and use of ear protectors correctly are influencing factors of the protective effect of ear protectors for noise-exposed workers.

[Analysis of verification results of protective effects of hearing protectors in different industries].

Objective: To get insight into the current practice of noise reduction effect of workers as they wore hearing protectors in different domestic enterprises and the possible affected factors. Methods: From October 2020 to April 2021, using a random sampling method, 1197 workers exposed to noise in petrochemical factories, textile factories, and parts manufacturing factories were selected as the study subjects. The noise reduction effect of hearing protectors worn by workers in daily use was tested using a hearing protector suitability testing system. The personal sound attenuation level (PAR) was compared among workers in three enterprises, Targeted intervention and repetitive testing were conducted for workers who did not meet the noise reduction effect required by the enterprise, and the changes in PAR of workers before and after the intervention were compared. The comparison of baseline PARs between two or more groups was performed using the Mann Whitney test, the comparison of baseline PARs with post intervention PARs was performed using the Wilcoxon signed rank sum test, and the comparison of qualitative data between two or more groups was performed using the Chi square test. Results: The median baseline PAR for all workers was 15 dB. Men, age<30 years old, education level at or above college level, working experience of 5 to 15 years, and those who used hearing protectors for 5 to 15 years had higher PARs, with statistically significant differences (P<0.05). The median difference in baseline PAR among workers from three enterprises was statistically significant (H=175.06, P<0.01). The median PAR of subjects who did not pass the baseline increased from 3 dB to 21 dB after intervention (Z=-27.92, P<0.01) . Conclusion: Some workers wearing hearing protectors do not meet the required PAR, and low PARs may be related to incorrect wearing methods and incorrect selection of hearing protectors. As a tool for testing, training, and assisting in selection, the hearing protector suitability testing system is of great significance for worker hearing protection.

Analysis of verification results of protective effects of hearing protectors in different industries / 中华劳动卫生职业病杂志

Objective: To get insight into the current practice of noise reduction effect of workers as they wore hearing protectors in different domestic enterprises and the possible affected factors. Methods: From October 2020 to April 2021, using a random sampling method, 1197 workers exposed to noise in petrochemical factories, textile factories, and parts manufacturing factories were selected as the study subjects. The noise reduction effect of hearing protectors worn by workers in daily use was tested using a hearing protector suitability testing system. The personal sound attenuation level (PAR) was compared among workers in three enterprises, Targeted intervention and repetitive testing were conducted for workers who did not meet the noise reduction effect required by the enterprise, and the changes in PAR of workers before and after the intervention were compared. The comparison of baseline PARs between two or more groups was performed using the Mann Whitney test, the comparison of baseline PARs with post intervention PARs was performed using the Wilcoxon signed rank sum test, and the comparison of qualitative data between two or more groups was performed using the Chi square test. Results: The median baseline PAR for all workers was 15 dB. Men, age<30 years old, education level at or above college level, working experience of 5 to 15 years, and those who used hearing protectors for 5 to 15 years had higher PARs, with statistically significant differences (P<0.05). The median difference in baseline PAR among workers from three enterprises was statistically significant (H=175.06, P<0.01). The median PAR of subjects who did not pass the baseline increased from 3 dB to 21 dB after intervention (Z=-27.92, P<0.01) . Conclusion: Some workers wearing hearing protectors do not meet the required PAR, and low PARs may be related to incorrect wearing methods and incorrect selection of hearing protectors. As a tool for testing, training, and assisting in selection, the hearing protector suitability testing system is of great significance for worker hearing protection.

[Tests for the correct insertion of earplugs in the ear canal performed with the use of a portable device]. / Badania prawidlowego umieszczania wkladek przeciwhalasowych w przewodzie sluchowym z uzyciem przenosnego urzadzenia.

BACKGROUND: The aim of the study was to assess the correct insertion of earplugs in the ear canal by people with different knowledge regarding this matter. The use of hearing protectors leads to a reduction in the risk of hearing loss, which is part of environmental engineering. MATERIAL AND METHODS: Measurements of sound attenuation by earplugs were carried out with the participation of 21 people with no experience in the use of earplugs. The measurements were repeated until the subjects had read the instructions for the use of earplugs, and then after the subjects had been trained in the correct insertion of earplugs in the ear canal. The tests were carried out using a newly developed portable device for quick measurements of sound attenuation. RESULTS: Familiarizing the subjects with the instructions for use resulted in a sound attenuation value being 6.7 and 3.3 dB higher, at 250 and 4000 Hz, respectively, compared to the measurement when the subjects inserted earplugs in the ear canal without any guidance. An even greater increase in attenuation was observed when the subjects were trained to insert earplugs, at 9.2 dB (250 Hz) and 5.4 dB (4000 Hz), respectively. In most cases, the changes in attenuation as a result of providing guidance were statistically significant. CONCLUSIONS: Persons who have no experience in using earplugs have significant problems with their correct insertion. Reading the instructions for use does not guarantee that earplugs will be inserted correctly. Only the training showing how to insert the earplugs correctly results in people being able to do it correctly in most cases. Med Pr. 2021;72(5):521-8.

The influence of frequency component content on the selection result of hearing protectors.

Hearing protectors are selected for workstation noise using the octave band (OB), HML and SNR methods. The purpose of this study was to determine how the frequency components of the noise can affect the selection of hearing protectors. In total, 55 hearing protectors were selected for four types of real occurring noise, high-frequency noise, low-frequency noise and eight simulated noises. Analysis showed that the noise type affects the accuracy of selection carried out using the HML and SNR methods. For a noise with dominant frequency components, the result for selection carried out using the HML method deviates from the result using the OB method by 7 and 9 dB for earmuffs and earplugs, respectively. The study shows that use of the HML and SNR methods may lead to wrong assessment of the effectiveness of hearing protection with the selected hearing protectors.

Selection of Level-Dependent Hearing Protectors for Use in An Indoor Shooting Range.

The high sound pressure level generated by impulse noise produced in an indoor shooting range makes it necessary to protect the hearing of the people it affects. Due to the need for verbal communication during training at a shooting range, level-dependent hearing protectors are useful. The objective of this study was to answer the question of whether it is possible to properly protect the hearing of a shooting instructor using level-dependent hearing protectors. The noise parameters were measured in the places where the instructor was present at the shooting range. The division of a specific group of trained shooters into subgroups consisting of three or six simultaneously shooting individuals did not significantly affect the exposure of the shooting instructor to the noise. An assessment of noise reduction was carried out for eight models of earmuffs and two variants of earplugs, using computational methods for the selection of hearing protectors. Among the noise parameters, both the A-weighted equivalent sound pressure level and the C-weighted peak sound pressure level were taken into account. Depending on the assessment criterion adopted, a sufficient reduction in impulse noise was provided by either four or six out of the 10 hearing protectors included in the study.

Selection of Earmuffs and Other Personal Protective Equipment Used in Combination.

In a work environment, in addition to noise, people may be exposed to other harmful factors. Therefore, they wear both hearing protectors and other personal protective equipment (OPPE). Incorrect use of such a combination may increase the risk of hearing loss. The aim of this study was to determine whether the simultaneous use of earmuffs and other personal protective equipment could affect the effectiveness of hearing protection. The study was carried out under laboratory conditions using an acoustic test fixture. This fixture replicated the anatomical shapes of the head and the pinnae, and was also equipped with ear simulators. The study was carried out for five models of earmuffs and eight models of other personal protection equipment. We found that a change in the sound pressure level (SPL) under the earmuffs when using a full face respirator could reach up to 40 dB. On the other hand, the use of a half respirator had practically no adverse impact on the efficiency of hearing protection. In the selection process, it is recommended to consider safety spectacles equipped with thin temples, and half respirators equipped with band adjustment elements positioned on the facial part, rather than the back, of the user's head.

Noise reduction at the shooting range by means of level-dependent hearing protectors.

BACKGROUND: The aim of the tests was to establish the possibilities of reducing impulse noise by using level-dependent hearing protectors at a shooting range. The tests included 9 models of level-dependent earmuffs and 2 models of level-dependent earplugs. They were conducted in the presence of impulse noise generated by 7 types of firearms (pistols, a submachine gun, rifles, a shotgun). MATERIAL AND METHODS: The tests were conducted at an outdoor shooting range, using an acoustic test fixture that meets the requirements of the ANSI/ASA S12.42-2010 standard. Noise parameters were established for the noise reaching the microphones installed in the ear simulators of the acoustic test fixture: uncovered and protected by the tested hearing protectors. RESULTS: All 11 tested level-dependent hearing protectors allow to satisfactorily (below the exposure limit values) reduce the C-weighted peak sound pressure level and A-weighted maximum sound pressure level parameters of noise produced during shots from the 7 types of firearms included in the study. Moreover, in the most unfavorable case, the permissible number of impulses due to the value of the A-weighted noise exposure level normalized to an 8-h working day parameter exceeds 5000 per day. CONCLUSIONS: Level-dependent hearing protectors constitute the appropriate means to protect the hearing of people at a shooting range, while maintaining the functionality of these protection devices to transmit speech signals. Med Pr. 2019;70(3):265-73.

Localization of Vehicle Back-Up Alarms by Users of Level-Dependent Hearing Protectors under Industrial Noise Conditions Generated at a Forge.

The use of hearing protectors in various noisy workplaces is often necessary. For safety reasons, auditory information may be required to correctly localize the direction of an auditory danger signal. The purpose of this study was to verify if the selection of a specific level-dependent hearing protector may be important for the ability to localize a vehicle back-up alarm signal. The laboratory conditions reflected industrial conditions, under which an impulse noise was emitted against a background of continuous noise. A passive mode and a level-dependent mode (maximum and incomplete amplification) were considered. Four different models of level-dependent earmuffs and one model of level-dependent earplugs were included in the tests. The tests enabled differentiation between the individual hearing protectors. The use of earplugs in level-dependent mode did not significantly affect the ability to correctly localize the back-up alarm signal. For the earmuffs, the global assessment of the impact of a mode change revealed that, depending on the model of the earmuffs, the impact may be insignificant, but may also result in considerable impairment of the ability to localize the back-up alarm signal.

[Attenuation of ultrasonic noise in the 10-16 kHz frequency range by earplugs]. / Tlumienie halasu ultradzwiekowego w zakresie czestotliwosci 10­16 kHz przez wkladki przeciwhalasowe.

BACKGROUND: The aim of the study was to determine attenuation of earplugs for ultrasonic noise in the frequency range of 10-16 kHz. MATERIAL AND METHODS: The attenuation of earplugs in 1/3-octave-bands with the centre frequencies of 10 kHz, 12.5 kHz, and 16 kHz using the REAT (real-ear attenuation at threshold) method based on the measurements of hearing threshold of subjects. The study was carried out for 29 models of earplugs commonly used in the industry designed by various manufacturers, including 13 models of foam earplugs, 10 models of flanged earplugs, 5 models of headband earplugs and one model of no-roll earplugs. RESULTS: The values of the measured attenuation of earplugs are in the range 12.9-33.2 dB for the 10 kHz frequency band, 22.8-35.2 dB for the 12.5 kHz frequency band and 29.5-37.2 dB for the 16 kHz frequency band. The attenuation of earplugs in the frequency range 10-16 kHz has higher values (statistically significant changes) for foam earplugs than flanged earplugs (p = 0.0003 vs. p = 0.0006) or headband earplugs (p = 0.0002 vs. p = 0.04). CONCLUSIONS: The tests indicated that there is no uniform relation between the sound attenuation in the frequencies range of 10-16 kH and the catalogue H parameter (high-frequency attenuation value) of earplugs. Therefore, it is not possible to easily predict the attenuation of ultrasonic noise in the frequency range of 10-16 kHz using the sound attenuation data for the normally considered frequency range (up to 8 kHz). Med Pr 2018;69(4):395-402.

A study of the real-world noise attenuation of the current hearing protection devices in typical workplaces using Field Microphone in Real Ear method.

BACKGROUND: Actual noise reduction of the earmuffs is considered as one of the main challenges for the evaluation of the effectiveness of a hearing conservation program. OBJECTIVE: The current study aimed to determine the real world noise attenuation of current hearing protection devices in typical workplaces using a field microphone in real ear (FMIRE) method. METHODS: In this cross-sectional study, five common earmuffs were investigated among 50 workers in two industrial factories with different noise characteristics. Noise reduction data was measured with the use of earmuffs based on the ISO 11904 standard, field microphone in real ear method, using noise dosimeter (SVANTEK, model SV 102) equipped with a microphone SV 25 model. RESULTS: The actual insertion losses (IL) of the tested earmuffs in octave band were lower than the labeled insertion loss data (p < 0.05). The frequency nature of noise to which workers are exposed has noticeable effects on the actual noise reduction of earmuffs (p < 0.05). The results suggest that the proportion of time using earmuffs has a considerable impact on the effective noise reduction during the workday. CONCLUSIONS: Data about the ambient noise characteristics is a key criterion when evaluating the acoustic performance of hearing protectors in any workplaces. Comfort aspects should be considered as one of the most important criteria for long-term use and effective wearing of hearing protection devices. FMIRE could facilitate rapid and simple measurement of the actual performance of the current earmuffs employed by workers during different work activities.

Contemporary noise-induced hearing loss (NIHL) prevention.

Hearing impairment caused by noise, traditionally called - depending on the duration of exposure - acute or chronic acoustic trauma, includes, in addition to presbyacusis, the most common adult population of hearing impaired. In Poland - according to the report of the Central Statistical Office (GUS, 2011), the number of workers employed in NDN exceeded the noise level (85 dB) is about 200 thousand, the highest in the mining, metal and metal products production, textiles and wood production. According to the Regulation of the Council of Ministers of on June 30, 2009, on the list of occupational diseases (Journal of Laws No. 132, item 1115), it is defined as "bilateral permanent hearing loss of the cochlear or sensory-nerve type, expressed as an increase in hearing threshold of at least 45 dB in the ear better heard, calculated as an arithmetic mean for frequencies 1,2 and 3 kHz. Hearing impairments also occur in the military and police during field training and in combat where the source of acoustic injuries are firearms and pulse-inducing explosions (as in some industries) with high C peak levels (Lc peak) Time to rise to a maximum of <1 ms. The prevalence of loud music listening, particularly by personal stereo players, is also affecting children and adolescents with audiometric hearing loss, according to the World Health Organization (WHO) estimates of around 15-20%. The preventive action strategy is defined by the European Union legislation and the national implementing legislation that reduces or eliminates the risk and reduces (if not eliminated), taking into account available technical and organizational solutions to minimize the risk of hearing damage. If you can not reduce the noise levels with technical and organizational methods, you need individual hearing protectors. Ear protectors may be equipped with electronic systems with active noise reduction (which can improve low and medium frequency performance), adjustable attenuation (improves speech intelligibility and perception of warning signals), and wireless communication for verbal communication.

¿Son los tapones auditivos eficaces para prevenir los efectos de la contaminación auditiva mediante la atenuación sonora? / Are ear plugs effective in preventing the effects of auditory contamination through sound attenuation?

Contexto: los efectos de la exposición a la contaminación sonora incluyen síntomas auditivos como hipoacusia, elevación del umbral auditivo, trauma acústico y también no auditivos de tipo psicológico, físico y social. Material y métodos: estudio descriptivo analítico y transversal para determinar la eficacia de la atenuación sonora de los protectores auditivos personalizados en un grupo de 33 pacientes hombres sin alteraciones físicas del conducto auditivo externo, mediante la comparación de las respuestas obtenidas en el oído real libre y sin amplificación (Real-Ear Unaided Response) y con el oído herméticamente ocluido por medio de un tapón de silicona hecho a la medida (Real-Ear Occluded), ante la presencia de un ruido externo estable de banda ancha de 65 dB de intensidad, utilizando para ello un equipo de precisión certificado con normas ISO (Verifit de Audioscan). Resultados: se encontró que existe mayor protección a los decibeles altos con las frecuencias: 2000 Hz, 3000 Hz y 4000 Hz, bajando de 65 a 40 decibeles que traduce una reducción del 61%; no existe diferencia significativa entre ambos oídos, lo cual se explica por las particularidades en las formas anatómicas, profundidad de la inserción y la adecuada colocación de la sonda microfónica. Los valores promedio de atenuación bilateral en dB SPL que se logra en las diferentes frecuencias con tapones personalizados de protección auditiva varían dependiendo de la misma, con 250 Hz es de 9,97 en el oído derecho y 9,36 en el oído izquierdo y con 6000 Hz 15,28 en el oído derecho y 13,64 en el oído izquierdo. Una mayor atenuación se encontró con 3000 Hz (OD: 32,11 OI: 30,69), 2000 Hz (OD: 28,33 OI: 28,47) y 4000 Hz (OD: 27,28 OI: 26,67). Conclusión: el uso de protectores auditivo logra una evidente reducción de los niveles sonoros, sobre todo con frecuencias agudas (primeras) cuyos umbrales se afectan al someterse a elevados niveles de ruido por tiempos prolongados. (AU)

Context: the effects of exposure to noise pollution include auditory symptoms: hearing loss, elevation of the auditory threshold, acoustic trauma and also non-auditory psychological, physical and social. Material and methods: a descriptive, analytical, cross-sectional study, the efficacy of the sound attenuation of the personalized hearing protectors was determined in a group of 33 male patients without physical alterations in the external auditory canal, by means of the comparison of the responses obtained in the ear Real-Ear Unaided Response, and with the ear sealed by means of a custom-made silicone plug (Real-Ear Occluded), in the presence of stable external broadband noise of 65 dB Of intensity, using a precision equipment certified with ISO standards, the Verifit of Audioscan. Results: it was found that there is a greater protection to high decibels with frequencies 2000 Hz, 3000 Hz and 4000 Hz, falling from 65 to 40 decibels, which means a reduction of 61%, there is no significant difference between both ears, Which is explained by the particularities in the anatomical forms, depth of insertion and the proper placement of the microphone probe. The average bilateral attenuation values in dB SPL that is achieved in the different frequencies with personalized ear protection plugs vary depending on the same, with 250 Hz being 9.97 in the right ear and 9.36 in the left ear and with 6000 Hz 15.28 in the right ear and 13.64 in the left ear. Greater attenuation was found with 3000 Hz (OD: 32.11 OI: 30.69), 2000 Hz (OD: 28.33 OI: 28.47) and 4000 Hz (OD: 27.28 OI: 26.67). Conclusion: the use of hearing protectors; Achieves an evident reduction of the sound levels, especially with acute frequencies, which are the first ones whose thresholds are affected when undergoing high levels of noise for prolonged times. Keywords: sound attenuation, hearing protectors, noise induced hearing loss, auditory contamination

[Attenuation of earmuffs used simultaneously with respiratory protective devices]. / Tlumienie dzwieku nauszników przeciwhalasowych stosowanych jednoczesnie ze sprzetem ochrony ukladu oddechowego.

BACKGROUND: In the work environment, apart from the noise, employees may be exposed to other harmful factors. Therefore, they wear hearing protectors and other personal protective equipment. The aim of the study was to determine whether simultaneous use of earmuffs and respiratory protective devices affects the attenuation of earmuffs. MATERIAL AND METHODS: The study was conducted in laboratory conditions using the subjective REAT (Real Ear Attenuation at Threshold) and objective MIRE (Microphone in Real Ear) methods. The REAT method was used to measure sound attenuation of earmuffs, while MIRE was used to determine changes in attenuation of earmuffs due to the use of other personal protective equipment. RESULTS: The study showed reduction in attenuation of earmuffs due to the use of a full face mask up to 20 dB. Using a full face mask causes that attenuation of earmuffs in the low frequency range is close to zero. Reduction in attenuation due to the use of half masks for complete with particle filters (half masks) is 3-15 dB. Simultaneous use of earmuffs and filtering half masks makes small changes in attenuation not exceeding 3 dB. CONCLUSIONS: The study showed that full face masks give the greatest reduction in attenuation of earmuffs. On the other hand, the least reduction is observed in the case of filtering half masks. There is a significant difference between the reduction in attenuation of earmuffs worn with half masks for complete with particle filters because they may be equipped with different kind of the head strap. Med Pr 2017;68(3):349-361.

Sensory reweighting after loss of auditory cues in healthy adults.

We maintain our balance using information provided by the visual, somatosensory, and vestibular systems on the position of our body in space. Recent evidence has suggested that auditory input also plays a significant role for postural control, yet further investigations are required to better understand the contributions of audition to this process in healthy adults. To date, the process of sensory reweighting when auditory cues are disturbed during postural control has been overlooked. The aim of this study is to determine the impact of hearing protection on sensory reweighting for postural control in healthy adults. For this, we studied 14 healthy adults on a force platform using four different postural conditions either with or without attenuation of auditory cues. Our results suggest that disturbing auditory cues increases the reliance on visual cues for postural control. This is the first study to demonstrate such a sensory reweighting occurs in the event of a sudden disturbance of auditory cues in healthy adults.

Use of moulded hearing protectors by child care workers - an interventional pilot study.

BACKGROUND: Employees of a multi-site institution for children and adolescents started to wear moulded hearing protectors (MHPs) during working hours, as they were suffering from a high level of noise exposure. It was agreed with the institutional physician and the German Institution for Statutory Accident Insurance and Prevention in the Health and Welfare Services (BGW) that this presented an opportunity to perform a scientific study to investigate potential beneficial effects on risk of burnout and subjective noise exposure at work when child care workers wear MHPs. METHODS: This was an intervention study which compared the initial values with those after a follow-up of 12 months. All teaching child care workers employed by the multi-site institution were offered the opportunity to take part. Forty-five (45) employees in 16 institutions participated. The subjects were provided with personally adapted MHPs and documented the periods of wear in a diary. At the start and end of the intervention, the subjects had to answer a questionnaire related to subjective noise exposure and burnout risk. In parallel, employees were surveyed who had not taken part in the intervention. RESULTS: Thirty-three (33) subjects took part in the follow-up after 12 months (follow-up rate 73 %). The median period of wear of MHPs was 34.6 h. During the period of observation, the mean subjective noise exposure increased by 2.7 %, and mean burnout risk by 2.5 scale points (baseline: 55.2, follow-up 57.7). Neither difference was statistically significant. 67 % of the participants reported that they were still capable of fulfilling their teaching duties when wearing the MHPs. In the reference group without the intervention, the increase in burnout risk was 3.9 points, which was even less favourable (baseline: 50.6, follow-up: 54.5). CONCLUSIONS: Within the working environment of the child care workers, wearing MHPs did not reduce subjective noise exposure or burnout risk; the satisfaction of the study subjects with wearing MHPs decreased over time. There were however signs that the level of stress increased over time and that this might have been alleviated in the intervention group by wearing MHPs.

Directivity of hearing of auditory danger signal emitted by overhead crane.

BACKGROUND: The objective of the research has been to provide an answer to the question of what the possibilities of determining the direction of approach of the auditory danger signal emitted by an overhead crane appropriately are. Cases of use and no use of earmuffs (in the passive mode and level-dependent ones) were all taken into consideration. MATERIAL AND METHODS: The auditory danger signal and ambient noise were recorded in an industrial hall. Signals were reproduced at an experimental set-up, using a large number of speakers. Eight speakers for reproduction of the auditory danger signal were placed above a subject's head. The study participants would indicate the direction from which, according to them, the auditory danger signal was being emitted. RESULTS: The average percentage rate of the correct localization amounted to 75.8% when the overhead crane's signal wasn't masked. The presence of ambient noise caused a reduction of the number of correctly identified localization to 66.6%. The use of earmuffs in the passive mode resulted in the worst results (44.5%). There is some improvement when level-dependent earmuffs are used (57.3%). CONCLUSIONS: In situations where it is important to identify the direction from which the auditory danger signal generated by the crane's signaling device is approaching, it is beneficial to use level-dependent earmuffs rather than earmuffs in the passive mode. Correct identification of whether the auditory danger signal generated by the crane's signaling device is approaching from the left or right side is almost perfect, however correct identification of whether the signal is approaching from the front or back of a person is not always possible. Med Pr 2016;67(5):589-597.

Social Desirability Bias in Self-Reporting of Hearing Protector Use among Farm Operators.

OBJECTIVE: The purposes of this study were (i) to examine the relationship between reported hearing protector use and social desirability bias, and (ii) to compare results of the Marlowe-Crowne social desirability instrument when administered using two different methods (i.e. online and by telephone). METHODS: A shortened version of the Marlowe-Crowne social desirability instrument, as well as a self-administered instrument measuring use of hearing protectors, was administered to 497 participants in a study of hearing protector use. The relationship between hearing protector use and social desirability bias was examined using regression analysis. The results of two methods of administration of the Marlowe-Crowne social desirability instrument were compared using t-tests and regression analysis. RESULTS: Reliability (using Cronbach's alpha) for the shortened seven-item scale for this sample was 0.58. There was no evidence of a relationship between reported hearing protector use and social desirability reporting bias, as measured by the shortened Marlowe-Crowne. The difference in results by method of administration (i.e. online, telephone) was very small. CONCLUSIONS: This is the first published study to measure social desirability bias in reporting of hearing protector use among farmers. Findings of this study do not support the presence of social desirability bias in farmers' reporting of hearing protector use, lending support for the validity of self-report in hearing protector use in this population.

Consistency of attenuation across multiple fittings of custom and non-custom earplugs.

Hearing protection devices (HPDs) play a significant role in protecting workers from occupational noise-induced hearing loss. Individual HPD fit-testing estimates the amount of protection, or attenuation, that an individual achieves from a given HPD as it is worn. Results from a single fit-test may not be representative of real-world HPD performance over time, however, due to inconsistency in how the individual fits the HPD from time to time. In this study, the effects of HPD type and user training on the consistency of attenuation achieved across multiple fittings were evaluated in a within-subjects design. Attenuation measurements using a real-ear attenuation at threshold procedure were obtained on 30 participants wearing custom-molded and non-custom earplugs. The subjects were initially naive to proper earplug insertion techniques and later received one-on-one training for the second half of the attenuation measurements. Consistency, or reliability, of fit was assessed using (i) the standard deviation of the 'distance to ear mean attenuation', a measure of fitting uncertainty, and (ii) the standard deviation of the attenuation values across multiple fit-tests for each subject. The custom earplug provided statistically significantly better consistency of attenuation than the non-custom earplug at 500, 1000, and 2000 Hz. Training effects were statistically significant at 250, 500, and 1000 Hz and at the Personal Attenuation Rating. No interactions were statistically significant. These results indicate that, in general, subjects obtained more consistent attenuation with the custom earplugs than with the non-custom earplugs and that consistency improved with training for both earplug types.