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Localisable Alarms
Published in Neville A. Stanton, Judy Edworthy, Human Factors in Auditory Warnings, 2019
Approximately 200 participants (age range 19 to 57 years) were tested. They all had previous driving experience. A hearing test, in the form of an audiogram, which tested the ability to hear a range of frequencies, was performed on most participants. Eight loudspeakers were positioned at 45 degree intervals around the car’s azimuthal plane. The speakers were not visible to the participants, and the sound from each speaker was intensity and spectrality matched at a position which marked the driver’s head within the car. Matching each speaker in the way described resulted in the only variable each time the sound was played being that of direction. A response panel was mounted by the steering wheel in the car. There were 16 positions marked on the panel which represented the horizontal plane around the car. This allowed greater accuracy in determining the errors made by the participants than just having eight response buttons that corresponded directly to the number of speakers. On hearing a siren sound noise, participant drivers pressed the response button that they judged as equating to the location from which the sound originated. The sound source location was varied randomly, with the constraint that in each session all eight speaker positions were activated twice. The participants began trials after a period of familiarisation with the car (a 10-minute ‘drive’ along a preset rural route). During the trials the participants were asked to maintain a speed of 40 mph which the experimenter monitored continuously.
Chapter 3 Physics of the Senses
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
A measure of speech comprehension is the most desirable feature of a hearing test. Tests are used in which speech is presented to the subject at a range of intensities and their ability to understand is recorded. Speech audiometry is a valuable test of hearing, although the results depend not only on the hearing ability of the subject but also upon their ability to comprehend the language which is used. Sounds other than speech are also used: a tuning fork can be used by a trained person to assess hearing quite accurately. Sources of sound such as rattles are often used to test a child’s hearing: the sound level required to distract the child can be used as evidence of their having heard a sound. Two commonly used hearing tests are pure-tone audiometry and middle-ear impedance audiometry (tympanometry). Both of these tests use clinical electronic instruments, and they are discussed in detail in Chapter 15. Pure-tone audiometry relies on the co-operation of the subject to report on the audibility of sound over a range of frequencies and intensities to establish hearing threshold. Middle-ear impedance audiometry produces an objective measurement of the function of the middle ear.
Hearing Conservation Program
Published in Ron C. McKinnon, The Design, Implementation, and Audit of Occupational Health and Safety Management Systems, 2019
To determine hearing loss, a hearing test or audiogram is conducted. The person being tested is seated in an almost sound-proof booth and the audiometer feeds a tone through a set of earphones. As soon as the patient hears the signal, he or she pushes a button and a point is plotted on the audiogram. An audiogram tests the hearing level at different frequencies and plots a graph. Any perceivable reduction in the hearing ability of the patient is clearly indicated when the patient’s current tests are compared with an original base line test.
Obstructive sleep apnea risk and hearing impairment among occupational noise-exposed male workers
Published in Archives of Environmental & Occupational Health, 2023
Seunghyeon Cho, Won-Ju Park, Ji-Sung Ahn, Dae-Young Lim, Su-Hwan Kim, Jai-Dong Moon
In this cross-sectional study, we included 635 male workers out of a total of 650 workers aged 25–60 years from a tire-manufacturing factory. Because the number of female workers was too small (n = 15), they were excluded from the study. The production process in this factory runs 24 hours a day. All subjects performed the same type of shift (four-teams, eight hour rotating shift). In South Korea, the Occupational Safety and Health Act mandates noise measurement in the working environment if the noise exposure is >80 dBA. In addition, if there is a risk of exposure to noise ≥85 dBA, it is compulsory to undergo a special hearing examination that includes a hearing test every 2 years. In this study, all subjects were classified as occupational noise-exposed worker according to this standard. They underwent special health examinations from September to October 2018. We excluded subjects with a history of ear disease, otologic surgery, and acoustic trauma. Finally, 607 workers were included; all workers were administered the STOP-Bang questionnaire and underwent audiometric, clinical, and anthropometric tests. The present study was conducted in accordance with the ethical guidelines of the “Declaration of Helsinki” and was approved by the Institutional Review Board of Chonnam National University Hwasun Hospital, Hwasun, Korea (IRB number CNUHH-2016-150). Subjects were informed of the method and purpose of this study. In addition, each subject provided written, informed consent before participating.