The Characteristics of Spontaneous Otoacoustic Emissions in Full -term Newborns / 听力学及言语疾病杂志

Objective To analyze the characteristics of spontaneous otoacoustic emission in full-term newbo‐rns .Methods The Capella OAE equipment (Madsen ,Denmark) was used to test Spontaneous Otoacoustic Emission (SOAE) in 147 cases (236ears) who have passed the newborn hearing screening with TEOAE(Transient Evoked Otoacoustic Emissions) .Results The SOAE incidence was 56 .77% (male 41 .51% ,female 69 .23% ;left ear 49 .14% ,right ear 64 .17% ) .It was significantly higher in females (P<0 .05) and in right ear (P<0 .05) .The av‐erage amplitude was 11 .78 ± 8 .36 dB SPL( 11 .73 ± 8 .25 dB in male ,11 .81 ± 8 .43 dB SPL in female;11 .97 ± 8 .56 dB SPL in the left ear ,11 .65 ± 8 .22 dB SPL in the right ear) .There were significant differences in genders(P<0 .01) .The frequency of SOAE focused on 3 .2~ 3 .7 kHz(2 .9~3 .4 kHz in males ,3 .4~3 .9 kHz in females ;3 .2~3 .7 kHz in the left ears ,3 .2~3 .6 kHz in the right ears) .There were significant differences in genders(P<0 .01) .The average peak of SOAE was 3 .70 ± 2 .75(3 .86 ± 2 .87 in males ,3 .62 ± 2 .70 in females;3 .70 ± 3 .02 in the left ears ,3 .70 ± 2 .55 in the right ears) .There were no significant differences in genders and laterality .Conclusion The characteristics of SOAE in full-term newborns include higher incidences ,multiple peaks and high frequency distribution .

Evaluation of the Bilirubin Ototoxicity using ABR and DPOAE in Jaundiced Gunn Rats / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: In neonatal hyperbilirubinemia, accumulation of unconjugated bilirubin in the central auditory pathway and basal ganglia may cause sensorineural hearing loss and neurologic sequelae. The effect of unconjugated bilirubin on the brain is known well through auditory brainstem responses (ABRs). However, there is no evidence of pathologic changes in the cochlea. Jaundiced (jj) Gunn rats have been used as a good animal model for hyperbilirubinemia-related auditory dysfunction. The purpose of this study is to evaluate the bilirubin ototoxicity using ABR and DPOAE in jaundiced Gunn rats before and after sulfadimethoxine injection. MATERIALS AND METHOD: Experiments were conducted on three homozygous (jj) P19 (postnatal 19 days) littermates, one heterozygous Gunn rat, five P21 jj littermates, and one nj Gunn rat littermate. P21 jj and nj Gunn rats were re-tested in three weeks in the same condition. ABR with 100-microsecond pulse width click and DPOAEs at 8 kHz, 16 kHz and 22 kHz were measured before and after 1 mg/kg sulfadimethoxine injection. RESULTS: The thresholds of ABR were elevated in P19 and P21 group within the first day after injection and became normalized at several days after injection. Delay of wave II, III, IV and V were also observed. DPOAE showed no significant change after injection in all groups, meaning that the cochlea was not damaged. CONCLUSION: This study shows that bilirubin ototoxicity is related with pathologic changes at or higher than the brainstem level with intact cochlear function. Changes in ABR findings were only observed in P19 and P21 groups because they had higher bilirubin level in blood and their central auditory pathway is more immature than that found in the P42 group. In this study, we also found the possibility of spontaneous recovery from hyperbilirubinemia-related auditory toxicity.

Properties of SOAEs and Their Correlation with TEOAEs in Neonates / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Transient evoked otoacoustic emissions (TEOAEs) have been used as a screening test for early detection of hearing loss in newborns and infants, because most of the normal hearing show TEOAEs. But the lack of understanding about the properties of spontaneous otoacoustic emissions (SOAEs) has limited their usefulness on the clinical basis. This study was designed with the purpose to find out the properties of SOAEs and their correlation with TEOAEs. MATERIALS AND METHODS: TEOAE and SOAE tests were performed in 95 neonates (190 ears, male:female=47:48) of well baby clinic in DKUH. RESULTS: 1) The prevalence of SOAEs were 86.8% (165/190 ears):87.2% (82/94 ears) in male and 86.5% (83/96 ears) in female, 91% (86/95 ears) in the right ears and 83% (75/95 ears) in the left ears. 2) The number of peaks in SOAEs was 4.14+/-1.92 overally, 4.38+/-2.01 in right ears, 3.87+/-1.79 in left ears, and 4.34+/-1.95 in males and 3.94+/-1.88 in females. There was a significant difference between the right and the left ears. 3) The level of SOAEs was -18.4 to 22.6 dB SPL. The highest amplitude of SOAEs in each subject was 3.69+/-8.87 dB SPL. 4) The SOAE frequency was mainly between 1000 Hz and 4000 Hz, and most frequently between 3000 Hz and 4000 Hz. The mean frequency of the highest amplitude of SOAE was 2907+/-1092 Hz. 5) The highest amplitude of SOAE was correlated with the overall response amplitude of TEOAE (r=0.619, p<0.01), but not the number of peaks (r=0.086, p=0.272). CONCLUSION: Neonates have robust SOAEs, which correlated with their TEOAEs.