Understanding subtle changes in auditory function with otoacoustic emissions

Abstract

Otoacoustic emissions (OAEs), a sensitive measure of cochlear processing, may be altered by subtle changes in auditory function that are not measureable by usual clinical methods. We studied auditory function in carriers of genetic mutations related to recessive hereditary hearing loss where we hypothesized that carrying a single mutated copy may compromise auditory function and be reflected when sensitive assays are used. Parents who were confirmed carriers of recessive mutations associated with GJB2 (connexin 26) and obligate carriers of mutations related to recessive hearing loss not related to GJB2 mutations were compared to age and gender matched control subjects. All participants had normal pure tone and middle ear responses. Metrics included transient evoked OAEs and distortion product OAE fine structure. DPOAE fine structure was specifically explored based on the ability to isolate components that could be differentially affected by genetic mutations. The results support the hypothesis that carriers of gene mutations related to hearing loss display subtle auditory abnormalities that can be observed in OAEs. These findings will be related to other studies of subtle changes in OAEs in disorders affecting auditory function. [Supported by NIH NIDCD R01-DC03679 and VU Development Funds]