Audiological implications of earplugs used for the prevention of aural exostoses

Abstract

External auditory canal exostoses may be a preventable disease, so it is surprising that the regular use of water precautions is not greater among surfers. One reason for this is the impairment of hearing whilst wearing earplugs. The objective of this study is to establish the hearing impairment of commonly available earplugs used by surfers. Staff and patients with normal hearing were recruited to have pure tone audiometry performed multiple times, initially with no earplugs, and subsequently with earplugs. Three earplug types were tested which differed in their nature and material (prefabricated elastomer, custom-fitted silicone, and custom-fitted acrylic). Vented and non-vented forms of the earplugs were tested. 30 normal hearing ears were included. Two-tailed paired t-tests comparing hearing thresholds between different earplugs identified that the elastomer earplugs caused the least hearing impairment (p < 0.001). There was no significant difference in hearing thresholds between vented and non-vented elastomer earplugs (p = 0.148), but the difference between vented and non-vented forms of other earplugs was statistically significant (silicone p = 0.010, acrylic p = 0.018). Prefabricated ear plugs produce less hearing impairment than other commonly available earplugs. A customised earplug made of hard material causes the greatest impairment of hearing. We therefore recommend that for aquatic sports where hearing is important, a soft prefabricated earplug is preferable.