INFLUENCE OF EUSTACHIAN-TUBE DYSFUNCTION ON TRANSIENTLY EVOKED AND DISTORTION-PRODUCT OTOACOUSTIC EMISSIONS

Middle ear impedance plays an important role in the retrograde middle ear transfer and interpretation of otoacoustic emissions (OAE). Change s of emission spectra and reproducibility or absence of sound emission s can be caused by middle ear dysfunction. To avoid misinterpretation, especially in infant screening, we combined measurements of transient ly-evoked otoacoustic emissions (TEOAE), distortion products (DPOAE) a nd middle ear pressure. With a single acoustic probe ear canal baro-pr essure was adjusted individually to the middle ear pressure, allowing OAE to be measured at maximum compliance of the middle ear. Fifty chil dren (ages, 3-8 years) were examined with hypoventilation of the middl e ear. Twenty-five normally hearing adults were also studied. Positive and negative middle ear pressures significantly attenuated the amplit ude of low-frequency OAE (< 2 kHz), whereas high-frequency emissions w ere stable. Individual adaptations of static ear canal pressure elimin ated these alterations of TEOAE and DPOAE.