The Efficacy of the Hearing Threshold Level at 3 kHz I/O Curve in DPOAE in Screening the High Risk Neonates in NICU

Chang, Sun O; Choi, Byung Yoon; Hwang, Chan Ho; Ahn, Soon Hyun; Lee, Myung Chul; Oh, Seung Ha; Lim, Duk Hwan; Kim, Chong Sun; Kim, Beyong Il

Abstract

BACKGROUND AND OBJECTIVES: Universal infant hearing screening has been recommended by the National Institutes of Health. Although the distortion-product otoacoustic emissions (DPOAE) hold promise as a screening technique, the validity oftheir input/output function curve (I/O curve) in the screening of neonates has not been fully investigated. The aims of this study were to determine the efficacy of the I/O curve as a hearing screening test and to investigate the prevalence of sensorineural hearing loss (SNHL)(moderate to severe degree) in high risk neonates. MATERIALS AND METHOD: A total of 69 ears of 35 infants at risk for hearing loss were tested with both DPOAE and auditory brainstem responses (BR). Auditory brainstem response results were used as the standard for hearing. The hearing threshold level at 3 kHz in I/O curve and the amplitude of distortion product in the DP audiogram were calculated and compared with the results of ABR. Neonates whose hearing thresholds were worse than 60 dB in the I/O curve were regarded as 'test-positive' and neonates whose hearing thresholds were worse than 60dB in ABR were regarded as 'disease-positive'. The sensitivity and the specificity of each test were calculated and the correlations between the response of each test and ABR threshold were also studied.
RESULTS
The prevalence of SNHL in neonates in the SNUH neonatal intensive care unit was 5.79%. The sensitivity and specificity of the screening test using the I/O curve were 100% and 63.1%, respectively. The test using the DP amplitude for SNHL showed the sensitivity of 100% and the specificity of 18.46%. This was much lower than that of the screening test using the I/O curve. There was a positive correlation between the I/O threshold and ABR threshold (r=0.43), but there were no statistically significant correlations between the DP amplitude and the ABR threshold nor between the DP amplitude and the I/O threshold.
CONCLUSIONS
The test using the I/O threshold in DPOAE is suitable for the screening of the SNHL in neonates with high sensitivity and relatively high specificity. Moreover, the I/O threshold could predict the audiometric threshold more correctly than the DP amplitude could.