Quantitative estimation of minor conductive hearing loss with distortion product otoacoustic emissions in the guinea pig.
Subclinical conductive hearing losses (CHLs) can affect otoacoustic emissions and therefore limit their potential in the assessment of the cochlear function. Theoretical considerations to estimate a minor CHL from DPOAE measurements [Kummer et al. (2006). HNO 54, 457-467] are evaluated experimentally. They are based on the fact, that the level difference of the stimulus tones L(1) and L(2) for optimal excitation of the inner ear is given by L(1)=aL(2)+b. A CHL is presumed to attenuate both L(1) and L(2) to the same extent such that excitation of the inner ear is no longer optimal. From the change of L(1) that is necessary to restore optimal excitation of the inner ear and thus to produce maximal DPOAE levels, the CHL can be estimated. In 10 guinea pig ears an experimental CHL was produced, quantified by determination of compound action potential (CAP) thresholds at 8 kHz (CHL(CAP)) and estimated from DPOAE measurements at 8 kHz (CHL(DPOAE)). CHLs up to 12 dB could be assessed. CHL(DPOAE) correlated well with CHL(CAP) (R=0.741, p=0.0142). Mean difference between CHL(DPOAE) and CHL(CAP) was 4.2±2.6 dB. Estimation of minor CHL from DPOAE measurements might help to increase the diagnostic value of DPOAEs.
Department of Otorhinolaryngology, Head and Neck Surgery, Ludwig Maximilians University of Munich Medical Center, Marchioninistr. 15, 81377 Munich, Germany. bernhard.olzowy@med.uni-muenchen.de
Bernhard
B
Olzowy
Christoph
C
Deppe
Warangkana
W
Arpornchayanon
Martin
M
Canis
Sebastian
S
Strieth
Peter
P
Kummer
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000503:physiopathology; D001309:Auditory Threshold; D003051:Cochlea / Q000503:physiopathology*; D004195:Disease Models, Animal; D005071:Evoked Potentials; D005240:Feasibility Studies; D005260:Female; D006168:Guinea Pigs; D006314:Hearing Loss, Conductive / Q000175:diagnosis / Q000503:physiopathology*; D006320:Hearing Tests; D016014:Linear Models; D008297:Male; D017084:Otoacoustic Emissions, Spontaneous; D011237:Predictive Value of Tests