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

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.

Nonauditory Factors on Distortion Product Otoacoustic Emissions / 대한이비인후과학회지

Distortion product otoacoustic emissions(DPOAEs) have emerged as a promising clinical tool for measuring hearing status. This investigation examined the influence of four variable (test/retest reliability, test environment, gender and number of measurement points of resolution/octave) on the DPOAE response when obtained using a commercially available system, Otodynamics ILO92. Twenty normal hearing adults(10 males and 10 females) served as participants in this study. DPOAE measurements were obtained over three test sessions(baseline, 1 week retest, and a 10 minute retest following the one week measurement). Results showed that: 1) correlations were high across the three test sessions;2) test environment considerably affected the DPOAE measures below 4kHz;3) DPOAE amplitudes were significantly greater in females than males at 3 and 6kHz;and 4) DPOAE amplitudes were not affected significantly by the number of resolution points employed.