Occupational noise exposure is regulated by law, and protective measures are applied if the noise level exceeds 90 dB(A). The inferior exposure levels can cause an auditory fatigue which is defined as temporary and reversible hearing loss. Its mechanisms, however, remain largely underexplored with recent animal data suggesting that the long-term exposure (over several weeks) to noise above 85 dB Sound Pressure Level (SPL) may provoke a permanent damage to hearing. Furthermore, there is also a lack of research on cognitive and attentional repercussions of this phenomenon. Yet, this information could be important to prevent work-related errors and accidents. Lastly, although silent breaks (noise-free resting periods) throughout a day of work are preconized to limit the noise exposure, their effect on auditory fatigue has never been demonstrated.
Being a part of a larger project involving fundamental researchers (animal experimentation) and occupational health specialists (investigations at the workplace), this study aims:
* to evaluate how auditory fatigue caused by acute noise exposure in doses tolerated by law impacts auditory and cognitive performances in humans * to determine the effect of silent breaks proposed by occupational legislation on cognitive functioning * to issue new recommendations for the protection of workers exposed to noise
Healthy subjects aged between 18 and 35
With normal pure-tone audiometry data (air and bone conductions) on both ears: hearing thresholds ≤20 dB HL for each frequency tested - 125, 250, 500, 1000, 2000, 3000, 4000, 6000 and 8000 Hz
With normal Speech-in-noise test (the speech reception threshold (SRT) at which 50% recognition of the speech stimuli presented is achieved must be 3 dB higher than the standard test value established in subjects with normal hearing)
Without history of excessive noise exposure (1-MINUTE NOISE SCREEN ≤4)
History of sudden deafness or tinnitus lasting more than 48 hours
Conditions likely to affect hearing (tumours of the ear or base of the skull, etc.)
History of unresolved chronic otitis
Work in a noisy environment requiring workplace soundproofing or the use of personal protective equipment
University Hospital, Montpellier
Lead sponsor
National Research Agency, France
Collaborator