Low/High-risk Earmolds: New Technologies and their Application from 2019 to the Present

Until 2019, hearing aid molds were made with silicones that copied the shape of the ear, creating a positive and a negative mold to reproduce the shape and volume in cubic centimeters of the ear. This system had the disadvantage of lack of precision. Due to the pressure of the silicones during their placement in the ear, the soft tissues are deformed. This is especially important when the deafness is severe or profound. Because a very high sound power is required and sound leakage occurs. That leaking sound is feedback into the hearing aid microphone and generates a “Larsen effect.” Patients describe this sound feedback as very high-pitched beeps from the hearing aid that can be heard by family and others close to them. During the time that the hearing aid is whistling, the user loses information and hearing, as well as being annoying for the family. In the case of high-powered hearing aids, it is difficult to balance the sound leakage that generates the “Larsen effect” and the excessive pressure that forms the canal. Also bear in mind that the user of this type of hearing aid uses it all day, so a little discomfort translates into anguish and nervousness. This is not an easy task for the audiologist, nor for the laboratory technician making ear molds. They are known by the technicians as “High Risk Feedback Molds”. Recently, 3D laser light measurement has been used for measurements. By not having contact with the skin, this new technique allows the tissues not to deform. And it gives us a view from inside the ear (and this is another novelty) because they are done by means of a small probe that acts as a laser beam that we introduce into the ear canal itself.