Tympanometric patterns found in middle ear effusions.

In 120 ears of 67 children with a history of recurrent acute otitis media or otoscopic evidence of persistent middle ear effusion, or both, tympanograms were obtained using an otoadmittance meter and an electro-acoustic impedance bridge. Myringotomy was performed immediately following the tympanometric evaluation confirming the presence or absence of middle ear effusion. The comparison of myringotomy findings with a tympanometric pattern classification revealed 85.8% overall correct association with the presence or absence of a middle ear effusion for both instruments. In 83.3% of the cases, there was agreement in the classification of the tympanogram between the otoadmittance meter and the electro-acoustic bridge.