Tympanometric changes following acute otitis media in Japanese children.

Using tympanometry we investigated potential changes in both middle ears developing during and after unilateral acute otitis media (AOM) in Japanese children. In 144 children with unilateral (AOM), tympanometry was performed at presentation and was repeated at the 1st, 2nd, 3rd, and 4th weeks and then every 2 weeks up to 12 weeks after entry into the study. Type B tympanograms were recorded in 81 (56%) of the affected ears and in 37 (26%) of the unaffected ears at presentation. Twelve weeks after AOM, the type B tympanogram was still observed in 21 (15%) of the affected ears and in 16 (11%) of the unaffected ears. Ears with type B changes at presentation showed a significantly slower recovery of middle ear ventilation than did those with either type A or type C1.