Influence of middle ear conditions on measurement of evoked otoacoustic emissions

Park, Hyoung Jin; Goh, Eui Kyung; Lee, Hyun Sun; Jang, Hyung Jun; Baek, Moo Jin; Yoon, Jong Keun; Chon, Kyong Myong

Abstract

BACKGROUND AND OBJECTIVES: Otoacoustic emissions (OAEs) are low level acoustic sounds of cochlear origin. They have several advantages over other methods in auditory testing, particularly in children. However, because of the crucial dependence of emission levels on the healthiness of the middle ear conduction system, some middle ear problems confound the interpretation of evoked OAEs (EOAEs). The purpose of this study is to evaluate the effects of middle ear condition (tympanometry) on DPOAEs and TEOAEs in normal hearers. Materials and Method : Tympanometry, TEOAEs and DPOAEs were measured in 42 subjects (68 ears) who were under 12 years old and have pure tone thresholds within 25 dB HL
RESULTS
The OAEs pass rates for the three groups were as follows: 95 % for TEOAEs and 90 % for DPOAEs in the tympanogram type A group; 12 % for TEOAEs and 12 % for DPOAEs in the tympanogram type B group; 27.3 % for TEOAEs and 13.6 % for DPOAEs in the tympanogram type C group. The pass rate and sensitivity of EOAEs were much higher in the type A group than in the type B and C groups.
CONCLUSION
OAEs are useful for screening the integrity of outer hair cells in the tympanogram type A group but not in the type B and C groups. Therefore, tympanometry that represents middle ear condition is recommended before the OAE test. In addition, if TEOAEs and DPOAEs are simultaneously performed, sensitivity will be increased.