BACKGROUND: Labeled noise reduction (NR) data presented by manufacturers are considered one of the main challenging issues for occupational experts in employing hearing protection devices (HPDs). This study aimed to determine the actual NR data of typical HPDs using the objective fit testing method with a microphone in real ear (MIRE) method. METHODS: Five available commercially earmuff protectors were investigated in 30 workers exposed to reference noise source according to the standard method, ISO 11904-1. Personal attenuation rating (PAR) of the earmuffs was measured based on the MIRE method using a noise dosimeter (SVANTEK, model SV 102). RESULTS: The results showed that means of PAR of the earmuffs are from 49% to 86% of the nominal NR rating. The PAR values of earmuffs when a typical eyewear was worn differed statistically (p < 0.05). It is revealed that a typical safety eyewear can reduce the mean of the PAR value by approximately 2.5 dB. The results also showed that measurements based on the MIRE method resulted in low variability. The variability in NR values between individuals, within individuals, and within earmuffs was not the statistically significant (p > 0.05). CONCLUSION: This study could provide local individual fit data. Ergonomic aspects of the earmuffs and different levels of users experience and awareness can be considered the main factors affecting individual fitting compared with the laboratory condition for acquiring the labeled NR data. Based on the obtained fit testing results, the field application of MIRE can be employed for complementary studies in real workstations while workers perform their regular work duties.
Ear Protective Devices ; Ear* ; Hearing* ; Humans ; Methods ; Noise

BACKGROUND AND OBJECTIVES: A rotation chair test has been used to evaluate the function of the horizontal semicircular canals. Currently, two chair systems according to the presence of cylindrical darkroom are used in a clinic setting. However, it has not been thoroughly investigated whether one system is superior to the other system or not. In this study, we aimed to compare test outcomes and subject convenience between two systems. SUBJECTS AND METHODS: Twenty subjects with no history of otologic disease were enrolled. Subjects were tested with two systems: system [A] with a cylindrical chamber and system [B] with no chamber. The results of sinusoidal harmonic acceleration (SHA), step velocity (SV), and visual fixation (VFX) tests were compared between the systems. Subject convenience was assessed with a questionnaire survey and results were compared between the systems. RESULTS: There were no significant differences in gain or asymmetry in SHA test between the systems. However, the phase of system [A] was significantly lower than that of system [B] at 0.16 Hz. There was no significant difference between the systems in directional preponderance (DP) gain or DP time constant. Regarding the VFX test, gain was higher in system [A] than system [B]. Subjects reported less stuffiness and less anxiety with system [B] than system [A], while preferring the system [A] goggles. CONCLUSIONS: A rotation chair system without a darkroom can provide a more comfortable experience for subjects in terms of stuffiness and anxiety, while showing comparable results in SHA and SV tests with a darkroom system.
Acceleration ; Anxiety ; Ear Diseases ; Eye Protective Devices ; Semicircular Canals

This study was conducted to investigate knowledge and attitude factor related to hearing conservation and to evaluate the effect of knowledge and attitude about noise on hearing conservation behavior and hearing loss among workers exposed to noise. We investigated the questionnaires of knowledge and attitude about noise and hearing conservation behavior and hearing loss among 355 study subjects from March, 1998 to June, 1998. The results were as follows; We extracted following 5 factors from 26 questionnaire items of knowledge and attitude about noise; knowledge of noise and concern to the control noise (factor 1), general perceived susceptibility (factor 2), relative perceived susceptibility compared with colleagues(factor 3), concern to the hearing protective devices(factor 4), concern to the hearing and noise assessment (factor 5). Knowledge and attitude factors affecting the hearing conservation behavior were general perceived susceptibility in the case of wearing hearing protective devices and knowledge of noise and concern to the control noise in the case of suggestion for hearing conservation. But, in the case of intentional avoiding noise exposure, concern to the hearing protective devices was a significant factor with concern to the hearing and noise assessment. Knowledge and attitude factors affecting hearing loss in 1 kHz were relative perceived susceptibility compared with colleagues and concern to the hearing protective devices, and in 4 KHz were relative perceived susceptibility compared with colleagues and general perceived susceptibility.
Ear Protective Devices ; Hearing Loss* ; Hearing* ; Noise* ; Questionnaires

OBJECTIVE: The objective of this study was to evaluate the degree of intelligible speech in workers wearing hearing protective devices and the differences in background noise type. METHODS: A total 82 shipyard company employees and normal hearing volunteers were recruited as subjects from a company in Ulsan: subjects were classified to the hearing-impaired group or to the control group according to hearing status. They were tested pure tone and speech audiometry in varying test environments including signal-to-noise ratio and background noise type in a headphone and in a free field environment. RESULTS: For both groups, the attenuation of hearing protective devices was greater at high frequencies. For the hearing-impaired group, speech discrimination scores differences between the unprotected and the protected ear were not significant between background noise type, when speech was presented at 65 dBA. However speech intelligibility in white noise background was lower than in the other background noise types when speech was presented at 75 dBA. CONCLUSIONS: Workers' speech intelligibility increased with an increasing signal-to-noise ratio. Speech intelligibility was also dependent on background noise type. Workers and their colleagues were trained to pronounce words more loudly and more clearly when they wearing hearing protective devices or other communication methods that do not use sound signal should be considered.
Audiometry, Speech ; Ear ; Ear Protective Devices ; Hearing ; Humans ; Noise ; Signal-To-Noise Ratio ; Speech Intelligibility ; Speech Perception

BACKGROUND AND OBJECTIVES: The ability to localize a sound source is one of the binaural hearing benefits in a horizontal plane based on interaural time difference and interaural intensity difference. Unilateral or bilateral asymmetric hearing loss will affect binaural hearing and lead to sound locating errors. In this cross sectional analytical descriptive study, the localization error was investigated when participants turned their heads to the sound source with closed eyes and after simulating unilateral hearing loss by placing earplugs inside the right ear canal. SUBJECTS AND METHODS: This cross sectional analytical descriptive study was carried out on 30 right-handed adults, 22 female and 8 male (average: 25 years, standard deviation: 3.16). They were selected with the available random access method. Horizontal localization was evaluated with five speakers located at 0, ±30, and ±60 degree azimuths at a 1-meter distance from the examinee. Narrow-band noise signals were delivered at 35 dB SL in two “without earplug” and “with earplug” situations and the results were compared. The study was performed between September and December 2016 in Tehran, Iran. RESULTS: Significant differences were observed in localization errors between the “with earplug” and “without earplug” situations. The localization differences were greater for left-side speakers (-30 and -60 degrees) compared with right-side speakers (+30 and +60 degrees). The differences were more apparent at 4,000 and 6,000 Hz, which confirmed the effect of unilateral simulated hearing loss on interaural latency differences. CONCLUSIONS: Simulating hearing loss by using an earplug in one ear (right) increased localization errors at all frequencies. The errors increased at higher frequencies.
Adult ; Ear ; Ear Canal ; Ear Protective Devices ; Female ; Head ; Hearing ; Hearing Loss ; Hearing Loss, Unilateral ; Humans ; Iran ; Male ; Methods ; Noise

PURPOSE: This study aimed to identify factors affecting the use of the hearing protection devices (HPDs) among workers exposed to noise using the Pender Health Promotion Model. METHODS: The 222 subjects came from thermal power plants with similar noise levels, which are between 80 dB and 90 dB in South Korea. Data were collected with self-administered questionnaires designed to measure concepts from the Health Promotion Model. RESULTS: Mean percent times of using the HPDs at their most recent job site were 50.9%, and 20.3% had never the HPDs. The predictors of HPD use were social modeling (OR = 1.380), perceived benefits (OR = 1.150), and working at noisy worksites (OR = 4.925) when the outcome was based on the "non-use" versus "used at least once". However, the predictors of HPD use were social modeling (OR = 1.795) and perceived benefits (OR = 1.139) based on the "less than half-of-the-time-use" versus "more than half-of-the-time-use". CONCLUSION: Social modeling and perceived benefits of using the HPDs are important for workers to keep minimal or certain level of using the HPDs.
Ear Protective Devices ; Health Promotion ; Hearing ; Noise ; Porphyrins ; Power Plants ; Republic of Korea ; Workplace ; Surveys and Questionnaires

OBJECTIVE: To compare effectiveness on correcting cranial and ear asymmetry between helmet therapy and counter positioning for deformational plagiocephaly (DP). METHODS: Retrospective data of children diagnosed with DP who visited our clinic from November 2010 to October 2012 were reviewed. Subjects < or =10 months of age who showed > or =10 mm of diagonal difference were included for analysis. For DP treatment, information on both helmet therapy and counter positioning was given and either of the two was chosen by each family. Head circumference, cranial asymmetry measurements including diagonal difference, cranial vault asymmetry index, radial symmetry index, and ear shift were obtained by 3-dimensional head-surface laser scan at the time of initiation and termination of therapy. RESULTS: Twenty-seven subjects were included: 21 had helmet therapy and 6 underwent counter positioning. There was no significant difference of baseline characteristics, head circumferences and cranial asymmetry measurements at the initiation of therapy. The mean duration of therapy was 4.30+/-1.27 months in the helmet therapy group and 4.08+/-0.95 months in the counter positioning group (p=0.770). While cranial asymmetry measurements improved in both groups, significantly more improvement was observed with helmet therapy. There was no significant difference of the head circumference growth between the two groups at the end of therapy. CONCLUSION: Helmet therapy resulted in more favorable outcomes in correcting cranial and ear asymmetry than counter positioning on moderate to severe DP without compromising head growth.
Cephalometry ; Child ; Ear ; Facial Asymmetry ; Head ; Head Protective Devices* ; Humans ; Patient Positioning ; Plagiocephaly, Nonsynostotic* ; Retrospective Studies

In order to compare post-health care between medium sized enterprises(50-300 employees) and a large enterprise(an automobile manufacture plant) and to evaluate factors related to post?health care performance of workers with noise induced hearing loss, this study was carried out. One hundred and eighty nine workers were surveyed to the questionnaire on general and occupational characteristics, receipt of the examination result, perception and attitudes toward special health examination, contentedness with post-health care performance on the examination result and reason not to have post-health care performance. The results were as follows: 1. The employee in large enterprise perform post-health care higher than medium sized enterprises and main control method was taking ear protective device. The 27.5% of workers with NJHL did not perform any post-health care. 2. Comparing with large enterprise, medium-sized enterprises had more interview with workers of NJHL and some enterprises performed more health education and more improvement of working environment. But there were a few medium-sized enterprises which did not provide ear protective device and had indifference manager. 3. The variables that significantly related to the post-health care of manager side was receipt of health examination result(p < 0.05), the post-health care of worker side were size of enterprise, age(p <0.05) and receipt of health examination result(p <0. 1).
Automobiles* ; Ear Protective Devices ; Health Education ; Hearing Loss* ; Hearing* ; Noise* ; Questionnaires

BACKGROUND: The understanding of the relationship between risk perception, knowledge, and protective behaviors could play a major role in occupational risk control and management. Research exploring how workers perceive, recognize, and react to risks in different occupational settings is scarce in Thailand. The aim of this study was to assess the relationship of noise-related risk perceptions and knowledge to the use of hearing protective devices (HPDs) among sawmill workers in Thailand. METHODS: Sawmill workers (n = 540) from four factories in Trang, Southern Thailand, participated in a questionnaire interview from December 2015 to January 2016. Descriptive statistics and linear regression models were used to explore the risk factors related to HPD use. Path diagram analysis was demonstrated and used to evaluate associations. RESULTS: Risk perception was significantly correlated with HPD use (p < 0.01), HPD training (p = 0.01), and the number of years of work experience (p = 0.03). Sawmill workers were likely to use HPDs based on their risk perception and HPD training. However, HPD training was inversely correlated with age and the number of years of work experience. CONCLUSION: The study highlights the importance of risk perceptions and knowledge, and these factors should be emphasized in the design and implementation of any personal safety intervention program for sawmill workers.
Ear Protective Devices ; Hearing* ; Humans ; Linear Models ; Risk Factors ; Rubber* ; Thailand ; Wood*

PURPOSE: The purpose of this study was to examine effects of music intervention on environmental stress and sleep quality in liver transplant patients who are receiving care in one-person isolation rooms of an ICU. METHODS: The study was a quasi-experimental design pre-and-post nonequivalent control group. Participants were 37 patients (18 in the experimental group and 19 in the control group) who, after receiving liver transplant, were hospitalized in one-person isolation rooms of the ICU. The study covered patients admitted between August 2016 and December 2017. Earplugs and sleep shades were provided as ordinary care to both experimental and control groups, and music intervention was provided to the experimental group three times a day for 30 minutes each from the first day of hospitalization. RESULTS: The first hypothesis, “The experimental group who received music intervention will experience a lower environmental stress level than the control group” was supported (Z=−3.212, p<.001). The second hypothesis, “The experimental group who received music intervention will experience a higher sleep quality than the control group” was also supported (t=3.715, p=.001). CONCLUSION: Findings show that music intervention is an effective nursing intervention to reduce environmental stress and improve sleep quality in liver transplant patients in the ICU.
Ear Protective Devices ; Hospitalization ; Humans ; Intensive Care Units ; Liver Transplantation ; Liver ; Music Therapy ; Music ; Nursing