The effect of middle ear pressure on transient evoked otoacoustic emissions.

To determine the effect of middle ear pressure on transient evoked otoacoustic emissions (TEOAEs), emissions were recorded in ears with tympanometric peak pressures < or = -100 daPa and audiometric thresholds < or = 30 dB HL at 500 through 2000 Hz. TEOAEs were alternately recorded at ambient pressure and at the tympanometric peak pressure. As demonstrated for the 14 ears tested, equalization of the middle ear pressure increased TEOAE amplitude. Reproducibility was similarly improved in 12 of 14 ears. Unequalized middle ear pressure attenuated low frequency emissions more than high frequency emissions. These amplitude and spectrum differences were consistent with previously reported observations of the effects of ear canal pressure on otoacoustic emissions. Results suggest that unequalized middle ear pressure may increase the occurrence of false positive failures, if otoacoustic emission testing is used for hearing screenings without consideration of middle ear pressure.