Correlation of transiently evoked otoacoustic emission measures to auditory thresholds

The presence of otoacoustic emissions is objective evidence of normal cochlear status. However, this test cannot be used to predict absolute auditory thresholds with accuracy. The criteria of normal otoacoustic emissions are not yet standardized and different measures of otoacoustic emissions have been used in various settings. In this study, the measures of reproducibility and otoacoustic emission amplitude are compared with regard to their correlation to pure-tone auditory (PTA) thresholds.

One hundred and seventeen subjects with normal hearing were included in the study. Subjects with previous audiological, otolaryngologic, or vestibular disease were excluded. A complete ENT and audiological work-up was performed, including transiently evoked otoacoustic emissions (TEOAEs). The equipment used for TEOAE testing was a DP Echoport ILO 292 Otodynamics analyzer connected to a portable personal computer. A full 260 low-noise samples were averaged. Correlation between PTA thresholds and either overall TEOAE amplitude or whole reproducibility was estimated using multiple regression analysis.

Correlation between acoustic thresholds at 250, 500, 1000, 2000, 4000 and 8000 Hz and either whole reproducibility or emission amplitude was highly significant for both measures. However, whole reproducibility was better correlated to acoustic thresholds at 250, 500, 1000, 2000, 4000 and 8000 Hz than was emission amplitude, and was more accurately predicted from multiple regression equations.

Reproducibility measures performed better than TEOAE amplitude levels in the prediction of auditory thresholds.