CLINICAL INTERPRETATIONS OF TRANSIENT OTOACOUSTIC EMISSIONS

Purpose: The purpose of this study was to characterize the relation of different ordinal patterns of transient otoacoustic emissions (TEOAES ) with respect to underlying otologic disorders and auditory status. P atients and Methods: The results of TEOAEs in 225 patients with variou s auditory disorders were investigated and compared with normative dat a established from 90 subjects of various ages. TEOAEs were categorize d according to four patterns: (1) normal (general response level withi n 90% of normative data, (2) reduced amplitude (general response level was greater than or equal to 2 dB peak sound pressure level (pSPL), b ut less than the mean -1.64 SD of the normative data), (3) abnormal mo rphology of frequency spectrum (general response level was within norm al limits, but reduced at greater than or equal to 2 individual octave frequencies between 1,000 and 5,000 Hz), and (4) total absence (respo nse level <2 dB pSPL). Results: This study showed that the normal patt ern of TEOAEs, in terms of response amplitude, varied with age. Our re sults further indicated that a reduced amplitude pattern of TEOAEs was noted in patients with a mild sensorineural hearing loss (SNHL), nega tive tympanometric pressure, a pressure-equalization tube, and Meniere 's disease. TEOAEs provided good frequency-specific information for pa tients with a noise-induced hearing loss. All patients with ossicular chain abnormalities, more than moderate SNHL, and a middle ear mass or effusion had total absence of TEOAEs. Patients with acoustic neuroma and brainstem lesions presented a complex profile of TEOAEs. In the fo llow-up of auditory function in patients undergoing otologic surgery, different patterns of TEOAEs between the preoperative and postoperativ e recordings were evident, which correlated with the hearing threshold s and middle ear status. The abnormal findings of TEOAEs due to specif ic auditory diseases were discussed. Conclusion: The interpretation of TEOAEs can be facilitated through an analysis of specific patterns an d in combination with other audiologic tests. Copyright (C) 1998 by W. B. Saunders Company.