To Örebro University

Background and Aim: Stapes surgery, the first-choice treatment for otosclerosis, restores the ossicular chain mobility. Otoacoustic emissions, particularly transient-evoked (TEOAEs) and distortion product (DPOAEs), are capable of noninvasively recording both conductive hearing and cochlear function.

Aim: The aim of this study was to process the effects of otosclerosis pre- and postoperatively, using otoacoustic emissions as an objective method of hearing evaluation.

Material and Methods: Thirty patients (23 women and 7 men) who were candidates for surgery were included in the study. The same patients were asked to be evaluated 2 and 5 months after surgery. All of the patients were evaluated with the use of pure tone audiometry, stapedial reflexes, tympanometry, TEOAE, and DPOAE recordings.

Results: Preoperatively, tympanometry showed type A or As tympanogram, and no stapedial reflexes were detected. Pure tone audiometry showed conductive hearing loss and mean air-bone gaps for frequencies 500 Hz to 4000 Hz between 15.167 dB and 33.167 dB. In 10% of the patients, TEOAEs were measured, whereas DPOAEs were detected in no cases (0%) before surgery. Two months after surgery, only 21 out of 30 patients were re-examined. Air-bone gaps were decreased for speech frequencies (500–4000 Hz), ranging from 8.1dB to 14.05 dB. In 52.4% of the patients who took the reappraisal, TEOAEs were measured, whereas DPOAEs were detected in 28 (57%) of them. Five months after surgery, air-bone gaps decreased even more, ranging between 4.32 dB and 13.4 dB. The presence of both TEOAEs and DPOAEs was increased in the 21 patients who underwent this re-examination, with TEOAEs detected in 54.55% and DPAOEs in 50% of them.

Conclusions: Despite hearing improvement and sufficient air-bone gap closing, OAEs are not always detected postoperatively. It seems that OAEs can be—in addition to an objective tool for testing ossicular chain's restoration—an approach to cochlear function after surgery.