Repetitive tympanometric screenings of two-year-old children.

240 healthy 2-year-old children were examined with tympanometry in November, February and May. One the whole, the tympanograms were somewhat improved at the spring evaluation compared with the winter evaluation. The type of tympanogram changed in half of the ears at each evaluation. In total, 64% of the ears have changed type at the three evaluations. The type B tympanogram, indicating a flat curve and secretory otitis, was improved in 64% of the ears that were originally type B, while in many other ears the tympanogram deteriorated to type B, such that 12,3% of the ears had secretory otitis at the first investigation, 14.6% at the second, and 11.3% at the third. Thus, in total 26.3% of the ears had at least one period of type B tympanogram or middle ear effusion and only 26.1% of the ears had a middle ear pressure of between 0 and 99 mmH2O at all three evaluations. Due to the large spontaneous normalization in this as well as in other materials, it may be assumed that 75--90% of all children have had at least one episode of secretory otitis.