Otoacoustic emissions and tympanometry in a general adult population in Sweden.

The present study concerns a general adult population in Sweden, not exposed to hazardous occupational noise. Tympanometry and spontaneous (SOAE), transient evoked (TEOAE) and distortion-product (DPOAE) otoacoustic emissions were investigated in 493 randomly selected men and women aged from 20 to 79 years. Effects of gender, age, ear side and middle ear state were determined, with and without adjusting for hearing threshold level. No statistically significant effects on middle ear pressure or compliance were present. For TEOAEs and DPOAEs, the effect of gender and age was statistically significant (p < 0.01), with larger signal levels for female subjects and young subjects, even after adjusting for hearing threshold level. No effect of middle ear pressure on otoacoustic emissions was present, but high middle ear compliance was associated with low emission levels (p < 0.01). Reference data for middle ear compliance and pressure and prevalence data on SOAEs, TEOAEs and DPOAEs for male and female subjects in different age groups were determined. Mean signal levels of TEOAEs and DPOAEs are presented.