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 measurable 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 mutation copy may compromise auditory function and be reflected when sensitive assays are used. Parents and siblings who were confirmed carriers of recessive mutations associated with GJB2 (connexin 26) or Usher syndrome, as well as obligate carriers of mutations related to recessive hearing loss of unknown genetic origin, were compared to age and gender matched control subjects. All participants had normal pure tone and middle ear responses. Metrics included transient OAEs, distortion product OAEs, and 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. [Work supported by NIH NIDCD R01-DC03679 and VU Development Funds.]