Comparison of Cartilage Conduction Hearing Devices Designed by Ear Impression and Computed Tomography

Abstract

The ear molds and shells of hearing devices are generally designed using ear impressions. Computed tomography (CT) can provide information concerning ear structure, which can be utilized in computer-aided design to create hearing devices. This study aimed to compare the differences in hearing devices designed using either ear impressions or CT images. The ear chip of a cartilage conduction (CC) hearing device was designed based on the ear impression and CT images of patients with aural atresia. Three patients with bilateral (n = 1) or unilateral (n = 2) aural atresia participated in this study. The aided thresholds and subjective evaluations were compared. There were no serious problems with the use of either device, and no remarkable differences were observed regarding their respective audiological and subjective benefits. Regarding the subjective patient preferences, the hearing aid with the device designed via CT imaging was better in three ears of two patients, whereas the wearing comfort of the transducer was better for the device designed via the ear impression. The subjective evaluation of appearance varied among the cases. Finally, a device that was designed using CT findings was purchased for one patient. CT images can be utilized in computer-aided design to create CC hearing devices.