Influence of the middle ear on the measurement of otoacoustic emissions

OBJECTIVE: Otoacoustic emissions (OAEs) provide an objective, non-invasive measurement of cochlear function. OAEs have proven to have a high sensitivity and reasonable specificity for hearing impairment diagnosis, especially when used for infant screening. The lower specificity could be due to middle ear function and that this affects otoacoustic emissions. PATIENTS AND METHODS: We have carried out a study in 1,202 ears with a mean age of 6.2 years. Clinical otoscopy and OAE measurements were performed in all cases and tympanometry in those cases with a negative result in the recorded emissions. RESULTS: Statistical analysis of tympanogram type indicated significant association with tympanogram type B and the absence of OAEs, as well as with otoscopic findings of secretory otitis media. CONCLUSIONS: Middle ear function must be taken into consideration when OAEs are used in clinical application. The problem of low specificity is mainly due to the fact that middle ear function affects the presence or absence of emissions with normal cochlear function.