A comparison of middle ear acoustic admittance in adults and 3-week-old infants based on multifrequency tympanometry

Abstract

The assessment of newborn hearing requires information on middle ear status yet the interpretation of tympanometry in newborns is unclear. This study aims to further our understanding of acoustic admittance in the newborn middle ear. Multifrequency tympanograms were recorded from sixteen 3-week-old infants (30 ears) and sixteen young normal-hearing adults (30 ears). Tympanometry was conducted using the Virtual 310 middle ear analyzer using 9 probe tone frequencies between 226 and 1000 Hz at roughly 100 Hz intervals. All infants passed a hearing screening using automated ABR (Algo II) shortly after birth (within 24 h) and again at 3-weeks of age. At 226 Hz, admittance tympanograms had a single peak in all adult ears while 60% of infant ears had multiple peaks or irregular patterns. At 1000 Hz admittance tympanograms had a single peak for 74% of infant ears while 78% of adult ears showed multiple peak or irregular patterns. Analyses of tympanometric shape (using the Vanhuyse classification scheme), as well as static admittance, static susceptance, and static conductance also reveal differences in adult and infant middle ear function. Implications for the clinical application of tympanometry in the first month of life will be discussed.