TY - JOUR AU - Benacchio, Simon AU - Varoquaux, Arthur AU - Wagnac, Eric AU - Doutres, Olivier AU - Callot, Virginie AU - Bendahan, David AU - Sgard, Franck PY - 2016/08/25 Y2 - 2024/03/28 TI - Ear canal deformations by various earplugs: An in situ investigation using MRI JF - Canadian Acoustics JA - Canadian Acoustics VL - 44 IS - 3 SE - Proceedings of the Acoustics Week in Canada DO - UR - https://jcaa.caa-aca.ca/index.php/jcaa/article/view/2908 SP - AB - <span style="color: #000000;">To be efficient, an Hearing Protection Device (</span><span style="text-decoration: underline; color: #000000;">HPD</span><span style="color: #000000;">) should be worn during the time the workers are exposed to high level noises in order to protect them against hearing losses or deafness hazards.</span> <pre style="text-indent: 0px; margin: 0px;"><span style="color: #000000;">Several reasons like the difficulty to communicate, aesthetic considerations or discomfort issues prevent the workers from wearing </span><span style="text-decoration: underline; color: #000000;">HPDs</span><span style="color: #000000;"> properly.</span></pre> <pre style="text-indent: 0px; margin: 0px;"><span style="color: #000000;">In the past, some indicators of physical (static pressure on the ear canal walls) and auditory (insertion loss, occlusion effect) discomfort induced by earplugs have been assessed using numerical models. However, most of these models rely on the assumption that the shapes of the open and occluded ear canal are identical which has never been demonstrated experimentally.</span></pre> <pre style="text-indent: 0px; margin: 0px;"><span style="color: #000000;">As the recent rise of medical imaging and numerical computing technologies allows for reconstructing the </span><span style="text-decoration: underline; color: #000000;">3D</span><span style="color: #000000;"> geometry of the outer ear, this study proposes to investigate the validity of this assumption. The shapes of the open and occluded ear canal of a human subject were obtained using high-resolution magnetic resonance imaging. Several kinds of earplugs were tested. Their non deformed shapes were obtained thanks to preliminary measurements. In each case the qualitative (from a radiologist assessment) and quantitative (from deformation measurements) comparison between the reconstructed occluded and open ear canal was carried out to evaluate whether and how both earplugs and ear canal deform.</span></pre> <pre style="text-indent: 0px; margin: 0px;"><span style="color: #000000;">The deformation of earplugs and tissues of the ear canal provides useful information to investigate how each earplug and skin should be modelled and characterized mechanically in order to predict the earplug sound attenuation and occlusion effect.</span></pre> ER -