Middle ear function in neonates.

This study was designed to investigate the middle ear function of neonates during the first few hours of life. Twenty normal babies, ranging in age from 2.5 to 20 hours old, were tested witn an electroacoustic impedance bridge. Measurements of the acoustic compliance of the tympanic membrane and tympanometry were obtained on both ears of each child. Results of compliance measurements indicated a median of 1,2 cu cm with a range of 0.25 to 1.65 cucm. Tympanometry results showed smooth notched-shaped tympanograms in most cases although afew M-shaped tympanograms were observed. All of the infants demonstrated normal middle ear pressures and mobile middle ear systems. The finding of normal middle ear function in these neonates suggest that mucus is not commonly present and therefore not a factor in infants' response to sound.