High frequency probe tone tympanometry in infants with middle ear effusion

The aim of this study was to investigate the use of high and low frequency probe tone tympanometry for the assessment of middle ear status in infants. The middle ear status of 26 infants under four months of age was investigated using tympanometry and otomicroscopy/pneumatic otoscopy. Nine infants were observed by expert otomicroscopy and pneumatic otoscopy to have middle ear effusion. Acoustic susceptance and conductance were measured using probe tone frequencies of 226, 678, and 1000 Hz. The results of tympanometry were compared with otomicroscopy and pneumatic otoscopy. A 1000 Hz probe tone critical peak susceptance magnitude of ≤ 0.93 mmho indicating the presence of middle ear effusion provided substantial strength of agreement with otomicroscopy/pneumatic otoscopy. A clinical tympanometry protocol for detecting middle ear effusion in infants under seven months of age is proposed. The protocol takes into account maturational effects on admittance magnitude by combining low and high frequency probe tone tympanometry.