title: Sound transmission by cartilage conduction in ear with fibrotic aural atresia.
abstract: A hearing aid using cartilage conduction (CC) has been proposed as an alternative to bone conduction (BC) hearing aids. The transducer developed for this application is lightweight, requires a much smaller fixation force than a BC hearing aid, and is more convenient to use. CC can be of great benefit to patients with fibrotic aural atresia. Fibrotic tissue connected to the ossicles provides an additional pathway (termed fibrotic tissue pathway) for sound to reach the cochlea by means of CC. To address the function of fibrotic tissue pathway, BC and CC thresholds were measured in six ears with fibrotic aural atresia. The relationship between the CC thresholds and the results of computed tomography was investigated. In the ears with the presence of a fibrotic tissue pathway, the CC thresholds were lower than the BC thresholds at 0.5 and 1.0 kHz. At 2.0 kHz, no significant difference was observed between the BC and CC thresholds. The current findings suggest that sound in the low to middle frequency range is transmitted more efficiently by CC via a fibrotic tissue pathway than BC. The development of hearing devices using CC can contribute to rehabilitation, particularly in patients with fibrotic aural atresia.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Nara Medical University, Nara, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Morimoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nishimura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hosoi
authors.forename: Osamu
authors.initials: O
authors.lastname: Saito
authors.forename: Fumi
authors.initials: F
authors.lastname: Fukuda
authors.forename: Ryota
authors.initials: R
authors.lastname: Shimokura
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Yamanaka
mesh_terms: D000161:Acoustic Stimulation; D000368:Aged; D001309:Auditory Threshold; D001844:Bone Conduction / Q000502:physiology*; D002648:Child; D004424:Ear Canal / Q000002:abnormalities*; D004425:Ear Cartilage / Q000503:physiopathology*; D005260:Female; D005355:Fibrosis; D006310:Hearing Aids; D006314:Hearing Loss, Conductive / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation*; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: acquired aural atresia; airborne sound; binaural 
  hearing; bone conduction; bone-anchored hearing aid; external 
  auditory canal; fibrotic tissue pathway; hearing aid; occlusion 
  effect; soft tissue pathway