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[Otoacoustic emissions (TEOAE and DPOAE) after middle ear operation]
B Lieberum1, B Held, M Schrader
1Universitäts-Hals-Nasen-Ohrenklinik Essen.
Background:
The behavior of transitory evoked otoacoustic emissions (TEOAE) and distortion products (DPOAE) in patients after middle ear surgery is unknown.
Methods:
We examined TEOAEs and DPOAEs in 37 ears following stapes surgery, 16 ears following tympanoplasty type I, and nine ears after reconstruction of the ossicular chain. In all patients, the postoperative conductive hearing loss was less than 15 dB HL. In some cases, there was additional sensorineural hearing loss in the high frequencies.
Results:
Surprisingly, TEOAEs were present only in 10 of 62 ears postoperatively compared to all 22 control subjects. TEOAEs were detected in four of 37 ears after stapes surgery, in six of 16 ears after tympanoplasty type I, and in none of the nine ears who had undergone reconstruction of the ossicular chain. DPOAEs were detected in only four of 31 ears postoperatively compared to all 22 control ears.
Conclusions:
These results and their relation to the retrograde OAE transmission in the middle ear are discussed. Changes enhancing the stiffness of the middle ear seem to have a greater effect than those enhancing the mass.