Examining the Role of the Tectorial Membrane in Otoacoustic Emission Generation

摘要

A mouse lacking CEACAM16, a member of the carcinoembryonic antigen-related cell adhesion molecule (CEACAM) family of proteins, shows changes in tectorial membrane (TM) structure including loss of a defined striated-sheet matrix, absence of Hensen's stripe and increased porosity. In spite of these changes, thresholds for distortion product emissions (DPOAEs) and auditory brainstem responses (ABR) are near normal for most frequencies in the mouse audiogram [11]. In contrast, stimulus frequency emissions (SFOAE) are larger in knockouts (KO) and the incidence of spontaneous emissions (SOAE) is -70% [5]. This latter statistic is remarkable considering that SOAEs are uncommon in normal wild-type (WT) mice. In order to understand how the TM might influence emissions, SFOAE magnitude and phase were examined and group delays computed. As in humans, an approximately one-cycle phase change is observed in association with SFOAE fine structure. In addition, CEACAM 16 KO mice and their WT controls showed similar group delays/phase slopes indicating no obvious changes in the mechanisms associated with emission generation.