Newsletter Extract

The following article was written by Bettina Wohlforth, AuD., CCC-A who contributes "Ask the Audiologist" articles to our newsletter on a regular basis. I have been asked to provide some information regarding ear-mold materials, styles and features. There are a handful of companies that provide earmolds for hearing aid use.   Earmold Materials - Their terms for the materials may vary, but all provide earmolds made of both hard and soft materials. Several factors are considered when selecting the material. These factors could include degree and origin of hearing loss, ear texture, the potential for earmold modifications and hypoallergenic considerations. The hard acrylic mold is appropriate for mild to moderate/severe hearing losses. Acrylic molds maintain their shape and color forever. When heat cured, acrylic material is considered to be hypoallergenic. Earmolds are available in several soft materials that vary from very soft and pliable to soft and yet somewhat rigid. Some of the soft materials shrink over time and all of them discolor with use. Some materials are more durable than others. For young children and rigid ears, we prefer a mold of soft material. For severe to profound hearing losses, a soft silicone mold works best. Earmold Function -Although cosmetics are considered, the earmold style should be more about function. The greater the hearing loss, the tighter the earmold should fit in the ear canal to minimize acoustic feedback (a whistling hearing aid). The softer materials and a mold that fills your entire ear (known as a shell) tend to work best, however, depending on the size and shape of the ear, there can be success with smaller molds. Open Fit Earmolds - In the case of good low frequency hearing ability, an “open” or “dome” mold may be the preferred choice.  The word open refers to how much space there is in the ear canal that is not filled by the mold. The open ear canal is to allow sound to pass by the mold and be perceived by your good low frequency hearing ability. You are not a candidate for an open fitting if there is a significant hearing loss in the lower frequencies. One advantage of an open fitting is a more natural or “normal” perception of sound, particularly your own voice. Closed “domes” are also available and are used for the in-the-office quick fitting of a behind-the-ear hearing aid. Sometimes these work well, but in many cases, a custom closed mold is necessary to minimize feedback and provide appropriate volume. Wax Guards -- As for wax guards on earmolds, these are commonly used on custom in-the-ear hearing aids. I have not seen them available on custom molds for behind-the-ear hearing aids. Earmolds are removable from hearing aids and can be washed with soap and water.