Noise exposure accounts for 22% of work-related health problems worldwide. Excessive noise not only leads to hearing loss and tinnitus, but it also increases the risk of developing cardiovascular disease. To provide protection, workers usually wear earplugs. However, the commonly available earplugs are often uncomfortable, as they do not fit everyone’s ears well
How can we improve the comfort and effectiveness of these earplugs? What aspects of the ear canal must be taken into account? To answer these questions, researchers from the Higher School of Technology (ÉTS) and the Research Institute for Safety and Security (IRSST) analyzed the changing structure of ear canals to find a relationship between their shapes and the effectiveness of three common canals. – Models used for earplugs.
Each one is unique
The ear canals are as unique as fingerprints. Therefore, to find the best compromise between comfort and efficiency, you need to understand the relationship between the shapes of the ear canals and earplugs.
Not only should earplugs fit inside the ear canal, but they also must apply pressure to the walls of the canal in order to seal it tight. However, if the plugs put too much pressure on the walls of the ear canal, they will cause the wearer pain.
To study these aspects, 3D models of volunteer workers’ ear canals were created. These people wore three different types of earplugs. To obtain the geometry of their ear canals, a molding material was injected to create the canal molds. These molds were then scanned by measuring software to determine the geometric properties of the ear canal, such as width at different locations and overall length.
The noise attenuation was then measured in the three samples of each volunteer’s earplugs. Two miniature microphones were fitted in and around the jacks to measure noise outside and inside the earplug.
Statistical analysis as well as AI-based algorithms helped classify ear canal morphology as a function of the degree of noise attenuation for each earplug.
The results of the study showed that the area of the ear canal called “the first elbow” is closely related to noise attenuation by earplugs. Similar body kits created with artificial intelligence will allow researchers to develop many tools for manufacturers, who will then be able to produce the most comfortable set of earplugs. This will allow prevention professionals to suggest appropriate models for each operator’s ear canals.