Tympanometry and otoacoustic emissions in a cohort of special care neonates

Abstract

Otoacoustic emission (OAE) screening and oto-admittance testing (678 Hz probe tone) were performed on both ears of 84 special care neonates, as part of a larger study of middle-ear effusion in neonates and infants. OAE results, tympanometry, and acoustic reflex results are all strongly and significantly associated. No evidence was found of any maturational effects in the results. Based on the findings, a tentative classification scheme for neonatal tympanograms is suggested. We conclude that 678 Hz tympanometry is a useful indicator of middle-ear status in very young babies, and that middle-ear effusion does strongly affect OAEs in neonates. OAEs are also strongly affected by negative middle-ear pressure (MEP), and mean MEP in ears failing OAE screens was significantly more negative than in those passing. The prevalence of abnormal tympanometry, which may indicate middle-ear effusion or dysfunction, was 20% of ears (29% of babies) in this group. It appears that middle-ear effusion could account for about half of the ears failing an OAE screen on the special care baby unit. We also find that length of stay on the special care baby unit is an important risk factor for development of middle-ear effusion: those on the unit for over 30 days have about four times the risk of bilateral abnormal tympanometry.

High frequency immittance for neonates: a normative study

“…Using 1000 Hz probe tone tympanometry, a peaked tympanogram incidence of 93.4% was reported in 228 ears compared to 95% for neonates (1-4 weeks of age) in the current study. The 1000 Hz tympanometric peak results for neonates in the current study and those reported by Kei et al 16 are also similar to a 678 Hz probe tone study conducted on a group of 200 special care baby unit babies, which indicated a 91% incidence of discernible peak tympanograms 21 .…”

“…A significant but poorer sensitivity rate of 57% was obtained for both tympanometry and acoustic reflexes for correctly identifying middle ear pathology. The decreased sensitivity may in part be attributed to the presence of middle ear effusion in a number of ears with present but decreased OAEs 16,21 . Such cases result in an overlap of true positive high frequency immittance results and false negative OAE results and lead to decreased immittance sensitivity.…”

“…Although present OAEs are not a perfect gold standard for the absence of middle ear pathology, their measurement is very dependent on an intact uncompromised middle ear system 16,21 . This reliance on normal or near normal middle ear functioning make OAE a useful measure for comparison to immittance results for providing sensitivity and specificity estimates for high frequency immittance testing in the absence of air and bone conduction tone ABR measurements.…”

Medidas imitanciométricas em crianças com ausência de emissões otoacústicas

“…These results match the ones published 17 , which state that middle ear effusion could happen in 50% of neonate ears who fail hearing screening with OAEs.…”

“…The authors consider middle ear effusion as a severe and significant cause of OAEs hearing screening failure in newborns at the intensive care units. 17 The present investigation carried out with infants found a conductive alteration, confirmed by the otorhinolaryngological clinical evaluation and by the Brain Stem Auditory Evoked Potential in 75% of those who failed TEOAEs (study group).…”