The Efficacy of the Alternating Technique in TEOAE Suppression by Contralateral Acoustic Stimulation / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Contralateral acoustic stimulation (CAS) is known to reduce the amplitude of the transient evoked otoacoustic emission (TEOAE) in human. However, the magnitude of the suppression effect evoked by CAS is too small to overcome the problems associated with fluctuating patient conditions as well as the environmental changes. We used an alternating technique to overcome this problem and compared the efficacy of this technique with the classic technique. The aims of this study are to show reduction of the amplitude of the TEOAE with CAS and to evaluate the efficacy of the alternating technique in measuring TEOAE suppression. MATERIALS AND METHOD: TEOAE suppression was measured in 24 ears of 12 normal hearing subjects. Both the alternating technique and classic technique were used in the same subject and condition. TEOAEs were recorded with an ILO 92 dual cannel OAE analyzer. In the alternating technique, one channel was used to stimulate and record TEOAEs from the test ear while the other channel was used to deliver 40, 50 and 60 dBSPL broadband noise to the contralateral ear. But in the classic technique, one channel was used to stimulate and record TEOAEs from the test ear while the broadband noise was applied to the contralateral ear via audiometer headphone. RESULTS: The overall contralateral noise of 40, 50 and 60 dBSPL reduced the amplitude of the TEOAE but only with 60dBSPL significantly reduced in both techniques. As larger CAS was given, the suppressive effect on the TEOAEs was greater in both techniques. But the significant difference was not found between the alternating technique and the classic technique. A total test time was 6 minutes for the alternating technique and 10 minutes for the classic technique. CONCLUSION: We confirmed the reduction of the amplitude of the TEOAE with CAS using both the techniques. No significant difference was found between the results of the alternating technique and the classal technique. We found that the alternating technique thereby decreasing the chance of fluctuating patient and environmental condition.