Author(s): Nélisse Hugues, Bonnet Fabien, Voix Jérémie
Noise at work and noise induced hearing loss (NIHL) are worldwide major problems in many industries. Although efficient noise control measures should be promoted and be directly applied to the damaging noise sources, hearing protection devices (HPDs) remain currently the most commonly used defense against NIHL. Evaluating HPDs effectiveness in the workplace is particularly contingent upon two variables: the ambient noise level and the attenuation of the HPD. Unfortunately, in practical workplace conditions, a precise knowledge of these metrics is rather uncommon. Large imprecisions may lead to improper HPD selection and may result in workers being underprotected or even overprotected. To address this problem, recent researches have involved the development of in-ear dosimetric devices, specifically designed to monitor the noise exposure levels directly in the ear canal in real-time. This paper presents the scientific and technical challenges of such a research project that targets the development of two in-ear dosimetric devices: an earplug-type and an open-ear insert. The main research topics are presented and discussed. They are: i) determination of personalized relationships between in-ear and free-field levels; ii) effect of ear canal occlusion on hearing sensitivity; iii) effect of self-induced noise; iv) hardware implementation. Representative results are presented for each topic to illustrate how in-ear dosimetry can be efficiently implemented and offer clear benefits for hearing conservation programs.
Name: Dr Hugues Nélisse