The Effects of Middle Ear Negative Pressure on the Transiently Evoked (TEOAEs)and Distortion Product (DPOAEs) Otoacoustic Emissions

Woo, Hoon Young; Kim, Joo Tea; Kwon, Dae Hyoung; Yoon, Kun Sik; Kim, In Bum

Abstract

BACKGROUND AND OBJECTIVES: The clinical utility of otoacoustic emissions (OAEs) has been well established in childhood hearing screenings. As middle ear negative pressure prevails in normal children, and since all OAEs must be transmitted through the middle ear before they can be measured in the ear canal, OAEs can be affected by middle ear negative pressure. The purpose of this study is to elucidate the effect of middle ear negative pressure on the detectability of OAEs. MATERIAL AND METHODS: TEOAEs were recorded for 36 ears using click before & after tonsillectomy and, or adenoidectomy (T and, or A) operations. Before & after T and or A operations, DPOAEs were generated at six geometric mean frequencies between 1-6 kHz for two different groups, Group I (40 ears) and Group II (36 ears). Group I: 3(f2/f1) ratios (1.21, 1.22 and 1.23) were used at the fixed stimulus level (70-70 dB SPL). Group II:3 stimulus levels were used (70-70 dB SPL, 60-70 dB SPL and 30-40 dB SPL).
RESULTS
The negative middle ear pressure attenuated low frequency emission more than high frequency emission.
CONCLUSION
Negative middle ear pressure may increase false alarm. So pneumatic otoscopy and aural immittance testing should be utilized to predict the feasibility of applying OAEs in childhood hearing screening test.