The effect of acrylic and PVC earmold material on REOR and REAR

Experimental earmolds which were otherwise identical but constructed from acrylic and polyvinylchloride material were compared by REAR and found to produce difference amplified responses in the ear canals of the children that participated in the study. The acrylic material produced uniformly and significantly greater amplitude. Pre- and post-test hearing aid and real-ear reliability results suggest that the observed REAR differences were not produced by measurement error and that they were not produced by insertion loss differences. This means that the observed response differences was produced by the transmission properties of the earmold material. The implication of this finding is that soft earmolds, which are often specified to prevent external feedback, may be compromising the acoustic response of the children's hearing aids.

The concept of fitting children with soft attenuating earmolds despite decreased amplitude in the hearing aid response, as well as the employment of acrylic earmolds in pediatric populations with mild-to-moderate hearing losses is advanced.