THE EFFECTS OF CHRONIC OTITIS-MEDIA WITH EFFUSION ON THE MEASUREMENT OF TRANSIENTLY EVOKED OTOACOUSTIC EMISSIONS

Otoacoustic emissions (OAEs) are low-level acoustic sounds of cochlear origin that can be recorded from the external auditory canal under we ll-controlled conditions. They are a natural by-product of normal audi tory physiology and may be divided into two general categories: sponta neous and evoked emissions. These emissions provide an objective, noni nvasive measurement of cochlear function that is accurate, rapid, and simple to perform. The clinical utility of OAEs has been extensively d escribed in both normally hearing subjects and subjects with sensorine ural hearing loss. The primary clinical applications of these emission s appear to be in neonatal screening and ototoxic monitoring. In this study, the effects of middle ear effusion on the production of evoked OAEs in children were assessed using preoperative tympanometric and ot oacoustic emissions testing. The study subjects were children with a h istory of chronic otitis media who had otoscopic findings suggestive o f middle ear effusion, An attempt was made to correlate the type of mi ddle ear effusion found at surgery with the presence or absence of pre operative otoacoustic emissions. Statistical analysis indicated that t he type of effusion in the middle ear does affect the presence or abse nce of emissions. These results tend to refute previous notions that O AEs are not measurable if the tympanogram is abnormal or fluid is pres ent in the middle ear space. A review of the pertinent literature in i ncluded, along with a general description of the types of OAEs and the ir clinical significance.