Contralateral suppression of otoacoustic emissions in tinnitus patients.
OBJECTIVE
To compare the functioning of the medial olivocochlear efferent system between tinnitus patients and control subjects.


METHODS
Prospective, nonrandomized controlled analysis of suppression of otoacoustic emissions with contralateral acoustic stimulation.


METHODS
Tertiary referral center.


METHODS
Initial analysis of 97 tinnitus patients and 44 control subjects with click-evoked otoacoustic emission measurement. If subjects had reproducible otoacoustic emissions at 80 dB SPL, suppression of otoacoustic emission with contralateral acoustic stimulation was measured with a 65-dB click stimulus. This resulted in inclusion of 44 ears of tinnitus patients and 57 ears of control subjects.


METHODS
Suppression of the otoacoustic emissions generated by the 65-dB click stimulus was tested using contralateral broadband noise at 70 dB SPL. Suppression was calculated in half-octave frequency bands centered at 1.0, 1.4, 2.0, 2.8, and 4.0 kHz.


METHODS
The amount of suppression of the OAE, calculated in half-octave frequency bands.


RESULTS
Otoacoustic emission amplitudes were equal in both groups. Contralateral suppression of the signal was found in both patients and controls. The amount of suppression was equal, except for the 2.0- and 2.8-kHz frequency bands in the right ear (p value of 0.03, 0.008, respectively), for which the patients had less suppression.


CONCLUSIONS
The suppression of otoacoustic emissions with CAS seems equally effective in tinnitus patients and healthy controls. The minor differences between both groups suggest subtle differences in the function of the medial olivocochlear efferent system.
Department of Otorhinolaryngology-Head and Neck Surgery, University of Groningen, Groningen, The Netherlands. l.i.geven@kno.umcg.nl
Leontien I
LI
Geven
Emile
E
de Kleine
Rolien H
RH
Free
Pim
P
van Dijk
D000161:Acoustic Stimulation; D001301:Audiometry, Pure-Tone; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D038781:Otoscopy; D014012:Tinnitus / Q000473:pathology / Q000503:physiopathology*